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SUBARUd
JULY/AUGUST 2005
VOLUME
NUMBER
114
6
FEATURES
26
COLD
FIRE
Dry
In Antarctica's
Valleys,
the deep chambers
and conduits
that
poured
hot lava onto the surface
are exposed as
else
nowhere
on Earth.
EDMOND
A.
MATHEZ
THE HEAT
OF THE NIGHT
An assassin hug's
32 IN
sensory journey
GRACIELA FLORES
38
UNHAPPY TRAILS
Forensic examination of ancient remains
sheds
new
light
on the emergence
of Florida's Seminole Indians.
CHRISTOPHER M. STOJANOWSKI
ON THE COVER:
Mother African elephant
and her
calf
mm
DEPARTMENTS
4
THE NATURAL
Down
MOMENT
the Hatch
Photograph by Solvin ZankI
6
UP FRONT
Notebook
Editor's
46
8
10
CONTRIBUTORS
THIS
LAND
Sand Trap
Robert H. Mohlenbrock
LETTERS
48
12
SAMPLINGS
BOOKSHELF
Laurence A Marschall
.
News from Nature
53
UNIVERSE
16
Heading Out
Neil deGmsse Tyson
nature.net
ChiU Out
Robert Anderson
COVER STORY
NATURALISTS
22
AT LARGE
Comeback Kids
Delia and Mark Owens
55
OUT THERE
Not Dead
Yet
Charles Liu
59
THE SKY
IN
JULY
Joe Rao
MUSEUM
60
AT THE
64
ENDPAPER
Messing About
Dru Clarke
PICTURE CREDITS: Page
Visit our
Web
8
site at
www.naturalhistorymag.com
AND AUGUST
A
"\
Has Evolution
Made A Monkey
Out df You?
J
Ape To Man
The Rev^ution
in Evolution.
August 7th 9pm/8c
THE HISTORY CHANNEL
History.com
\
u
X
Ul
N
to
DC
o
O)
LU
2005
4,
THE NATURAL
UP FRONT
MOMENT
See preceding two pages
G
reat In-
agua, the
Epilogue
southernmost
island in the
Bahamas, hosts
a massive col-
ony of wild
West Indian
flamingos
(Phoeiiicoptems
ruber ruber).
The
resident birds
—
about 50,000 of them nest
around the salty flats of Lake
Rosa,
a reservoir
grove
trees.
ringed by
man-
Photographer Solvin
Zankl chose one of the mangroves as a "hide." To minimize
the disruption, he installed himself and his camera at the end of
the breeding season,
when
only
ten pairs of nesting flamingos
were
still
newborn
mouth-feeding
their
chicks.
one ofispring each
which
year,
they nurture jointly. Rather than
regurgitating food for
it,
both
mom and dad secrete a bright
red, nutritious liquid in their
crop called "flamingo milk."
when
treated well.
Graciela Flores has a different perspective
on consequences;
afiier
years
work, she doesn't see many. Flores smdied heatsensing in the blood-sucking "assassin bug" of Latin America, the insect
vector of Chagas' disease ("In the Heat of the Night," page 32). The
ultimate goal of her research was to control a protozoan infection that
of careful
scientific
—and
The
the rose
tific
soine 20 irdUion people in the region. But the substantial scienknowledge of the assassin bug's behavior rarely seems to translate
into actions that could sharply reduce
Chagas' disease
is
although
tight:
it
its
impact.
may count
Money for fighting
Charles
Darwin among
been mostly an affliction of the poor. Research remains the province of a few dedicated scientists. The thatch-roofed houses where the insects thrive remain home
all at risk of a malady that can kiU or debilitate,
to 120 iniUion people
virtually without warning. Flores has now traded the lab bench for a
its
illustrious victims, the disease, Flores notes, has
—
hue of the adults' feathers
comes from high levels of hydrocarbon pigments (alpha- and be-
career in science journalism (she
ta-carotenes) in their diet. Fly
Edmond A. Mathez presents another kind of epilogue, in his story of
larvae
main
fare, filtered
is
an editor-at-large for
this
magazine).
geological discovery in a remote corner of Antarctica ("Cold Fire,"
and other microgoodies
are the birds'
page 26). Long before
it
was covered with
ice,
Antarctica was part of a
Gondwana. One hundred eighty million
of what was to become the frozen continent were
out fi-om lake water through the
supercontinent geologists
flamingo's pumplike beak.
years ago, parts
Unlike the baby pictured
here
a two-day-old hatchling
wracked with violent volcanism, the surface repeatedly covered with
hot lava, the underlying rock layers repeatedly pried apart by intruding
magma. Fast-forward in time, and a series of uplifts and deep cuts by
ancient rivers exposed the underground "plumbing" of the molten
rock. Miraculously, some of that plumbing occurs in valleys so dry they
—
most of the chicks Zankl obser\'ed were born a month earlier.
Zankl fondly recalls the day
several thousand chicks waddled
harbor bare rock for
past his hide, creating an incredi-
ble splashing sound.
"One
chick
as
all
call
to see.
Mathez and his colleagues reached this obscure Antarctic landscape
travelers from an unimaginably distant time (our present), to try to
could not keep up with the
make
group and decided to stay be!imd, between my tripod and
millions of years and a continent-size portion of the Earth's surface.
But
my
their collective
feet."
After
two hours, the
straggler finally rejoined the rau-
cous group.
6
Gregarious. Long-lived. Gentle
Dangerous when angered. No, not people; I'm talking about
elephants. Our cover story by Deha and Mark Owens, about
the aftermath of many years of elephant poaching in Zambia's North
Luangwa National Park ("Comeback Kids," page 22), tells of another
striking likeness between our species and elephants, revealed only in
times of desperation. Elephants from ravaged famihes act just like kids
firom broken homes. Young males form gangs and raise heU. Adolescent females get pregnant. The focus of social hfe shrinks from the
extended family to the single mom and her only calf The lore of
elephant society, vested in elders, dies with them. The good news is
that, thanks to the efforts of the authors and others, poaching has been
all but ehminated in the park. The bad news is that the consequences
of poaching Hve on.
afflicts
Parent flamingos usually have
color of the milk
Smart.
NATURAL HISTORY
—
Erin Espelie
July/August 2005
it
sense of the aftermath. Mathez's story encompasses hundreds of
begins in camp, where he and his twenty-tour companions toast
good fortune with Scotch whiskey splashed over
18,000-year-old glacial
ice.
Who
says natural science
is
dry?
—Peter Brown
You Have an Important
Engagement with Honduras
The Honduras
Institute of
Tourism, through
its
innovative
—SAVE
strategy, seeks to
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Active engagement of SAVE travelers with our communities will provide invaluable opportunities to
ral
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Honduras has much to offer SAVE
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travelers.
mangrove wetlands,
HONDURAS
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Nature's laboratory, culture's library.
mm
CONTRIBUTORS
Before embarking on a career as a freelance photographer, SOLVIN
ZANKL ("The
at
gy
Natural Moment," page 4) studied marine biolothe University of Kiel in Germany. His scientific interests
Mary Beth
on photographic essays featuring wildwork has been widely pubUshed, both in
are evident in his focus
behavior. Zankl's
life
Erin Espelie,
City,
EDMOND A. MATHEZ
include the soUdification of large
platinum deposits, the
Knight,
Managing Editor
Associate
("Cold
Fire,"
Graciela Flores Editor-at-Large
magma
of rocks, and the earCharles
McMurdo Dry
known
as
Valleys
of Antarctica, to study the ancient
Birthstone for Earth," on zircon
GRACIELA FLORES
crystals,
was published in
May
Donna M. Ponzoni
"A
Michael Shectman
2004.
Advertising Saks Representatives
—Metrocorp Marketing, 212-972-1
Neii> York
Duke
Defro/f—Barron Media
left
two collegescience and environ-
courses for high school teachers and co-authored
MM/y'f^m
biology textbooks, and has also completed a degree in
Natural History
New
York University. Flores is now an editor-at-large
magazine, and freelances for publications such as T7ie Scientist.
mental reporting
Browsing the
research to pursue
at
Toronto
cultural anthropological hterature
on ethnogenesis,
—^American
page 38) reahzed that his dissertation research in physianthropology might oSer clues to the rise of the Seminole,
Vice President, Science Education
Educational Advisory Board
Myles Gordon American Musesnn of Natural History
David Chesebrough Buffalo Museum of Science
Stephanie Ratcliffe Natural
Ronen Mir
History'
SciTech
Carol Valenta
St.
Museum of the Adiromiacks
On Museum
Hands
Louis Science Center
Natural History Mag.\zine, Inc.
Cecile Washington General Manager
Charles Rodin
Publishing Advisor
Native American groups during the
sixteenth and seventeenth centuries. Stojanowski
sistant professor
J
Charles E. Harris President, Chief Executive Officer
Charles Lalanne Chief Financial Officer
Judy Buller General Manager
work, based on human remains excavated from
among
Publishers Representatives Ltd., 416-363-1388
A/won'— Rickles and Co., 770-664-4567
Todd Happer
archaeological cemeteries in Florida and Georgia, documents
genetic changes
312-726-7800
310-710-7414
p
the Indian nation that figures so prominently in the history of
Florida. His
Sales,
—Sm)th Media Group, 646-638-4985
which new ethnic groups form, CHRISTOPHER M. STOJANOWSKI ("Unhappy
Trails,"
LLC. 313-268-3996
Associates,
National Direct Response
at
the process by
Sales,
&
Coast— On Course Media
Atlanta and
writing and editing. She has designed biology
Purdy
157,
212-986-6098
International Media,
C/jiCfl^t)— Robert
West
or "assassin bugs." Flores subsequently
Manager
Manager
For advertising information
call 646-356-6508
("In the
a career in science
Production
FulfiUnient
Jennifer Evans Business Administrator
Heat of the Night," page 32) earned her Ph.D. in
biology at the University of Buenos Aires in Argentina. There
she met the entomologist Josue Nunez and was drawn by Nunez's
contagious enthusiasm to the laboratory of insect physiology, run
by Nunez and Claudio Lazzari, to study the behavior of vinclmcas,
Publisher
W
basalt deposits
the Ferrar dolerites. His most recent article for Natural History,
Harris
E.
Edgar L. Harrison Advertising Director
Gale Page Consumer Marketing Director
Maria Volpe Promotion Director
Sonia
Paratore National Advertising Manager
Greenland. This past January he joined a group of geologists on an expedition
to the
Interns
Robert Anderson, Charles Liu, Laurence A, Marschall,
Richard Milner, Robert H. Mohlenbrock, Joe Rao,
Stephan Reebs, Adam Summers, Neil deGrasse Tyson
bodies, the origins of
electrical properties
Kazmira Pytlak
Kessler,
Contributing Editors
page 26) studies
the platinum mines of South Africa to the ancient rock-strewn mountains of
at
Mary
Kelleher,
J.
Donohue, Rebecca
Liz
He has done fieldwork in many parts of the world, from
ly Earth.
cal
T.
Avis Lang, Vittorio Maestro
Thomas Rosinski Associate Art Director
Hannah Black, Assistant Art Director
the geochemistry of the volatile elements. His research interests
level
Art Director
Michel DeMatteis
A geologist and curator in the department of earth and planetary
sciences at the American Museum of Natural History in New
York
Steven R. Black
Aberlin
Board of Editors
(www.solvinzankl.com).
site
Editor-m-Chief
Exemlive Editor
books and in such nature magazines as GEO and BBC Wildlife.
More of his award-winning wildlife images can be seen at his
Web
Brown
Peter
of anthropology
at
is
an as-
To contact
the Center for Bioarchaeological Research
Web
Arizona State University in Tempe.
us regarding
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toon):
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p.
Cover:
©Roy
12(top):
Toft/Natioml Geographic Image Collection;
©Lake County Museuni/CORBIS;
p.
pp.
4-5
&
6:
©Solvin Zankl/Namiepl.com;
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p.
p.
13(top):
12(car-
©Kaitn
13{left): ©Nic Miller/Organics [mage Library; p. 14{top): ©Voller Emst/eStock Photo; p. I4(left): ©The
©Babakin Space Center, The Planetary Society; p 22: Mardn Harvey/NHPA; p. 23: Map by Joe LeMonnier; p. 24: ©The Audior; p. 26-27: ©Andris Apse; p. 28: Maps by GecgraphX; p. 29: ©Bruce Marsh; p. 30: Diagram by Ian Worpole. reworked from a diagram by Bruce Marsh; p. 31: ©The Author; pp. 32-33: Illustration by Advanced Illustration; p. 34(left &; right):
©WHO/TDR/Stanimei^; pp 35 & 36: ©lllustrarions by Advanced Illustration; pp 38 & 39: ©CORBIS; p 40: CThe Library of Congress.
Geography and Map Division; pp. 41&43: Maps by Joe LeMonnier; p. 42: Illustration by Patricia J. ^X/yT^ne; p. 44: ©Bridgeman Art Library;
p. 46(leit): ©Wendy Shatdl/Bob Rozinski; pp. 46-47{top): ©Glenn Randall; p. 47: Map by Joe LeMonnier; p 48: ©USDA Forest Service; p.
48(inset): ©Barbara Sti-nadova/Photo Researchers, Inc.; p. 50: ©Russ Heinl and W. W. Norton & Company, Inc.; p. 52; ©Cynthia Hart Designer/CORBIS; p. 55: ©The Artist; p. 64: ©Bridgeman Art Library.
Warkenbn. Boston Univenity;
Artist; p. 16;
©NASA/JPL;
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LETTERS
Thomas
Dinosaur Geography
A. Norell and Xu
and I published
shows that both Appalachiosatmis and
Dryptosmmis were
son,
Xing's tyrannosaur history
of Tyrannosaurs," 5/05] was lucid
and informative, but I
["The
Varieties
would amend
sumption that
more
Well, -ItieY .sure
I
looK
North
in
li
chain, but also ate juve-
dorft]
ke me!
nile tyrannosaurs.
J
David R. Schwimmer
Columbus State University
Columbus, Georgia
primitive than
?£r^j^-=:=
their contemporaries
their asall
E. Williamj
Mark
Mark A. Norell and
Xu Xing reply: Our
the North Ameri-
American tyrannosaurs are
of Asian ancestry. During
can West. Ironically,
the Late Cretaceous the
primitive tyranno-
vast Western Interior Seaway spHt North America
into East and West. If the
sauroid, only appears
was in press before
by David R.
Schwimmer and his
colleagues was published,
in the fossil record
so the interesting results
eastern genera Appalachio-
least primitive, Tyran-
and Dryptosaurus are
derived from Asia, their ancestors must have crossed
nosaurus. Dryptosaurus
have been
the continent before the
nearly
saurus
was present, at
rmHion years ago.
Although that is
sea
Thomas D.
its
own
article
the paper
most
they found were not in-
the
as late as
cluded.
may
a "living fossil" in
time.
usefril to
look
least 1 00
rope, for
its
plausible,
also
It
might be
east, to
Eu-
Carr,
western United States. But
in the lowlands of the
Asian origin for tyranno-
at
the top of
cannot empirically reject an
Furthermore, several
southern U.S. the gigantic
saurs.
crocodilian, Deinosuchus,
primitive key Asian taxa,
Xu
the food chain." That
the sample
they used in their study, they
grew
to
more than
such
thirty-
very abundant.
is
as Dilong, Alectrosaurus,
and Alioramus, were not in-
three feet long and was
maintain that tyran-
nosaurs "hved
With
evident in Asia and the
nearest ancestry.
Messrs. Norell and
a recent cladistic analysis
that
Dryptosaurus, the
The animal
cluded in their
not only topped the food
analysis.
We
(Continued on page 54)
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iii:tu332lJ-SS
four.
States Leprosarium on Molofcai, Hawaii
But the geneticists found only
and
four: C,G,A; C,T,A; C,T,C;
Mapping out where and
in
T,T,C.
what pro-
portion each combination occurs today, the investigators realized, could
track the spread of the disease
through time and space.
Previously
it
was thought that
leprosy originated
in India
(which
still
was introEurope when the armies
has the most cases) and
duced
into
of Alexander the Great returned from
their Indian
campaign. But Monot,
Honore, and their colleagues
East Africa or the Near East
now
is
say
prob-
ably the birthplace of the disease.
From
there, leprosy spread around
the globe via
human
migration, trade,
and colonialism.
M. leprae was
West
likely
brought to
Africa, for instance,
by infected
explorers or traders from North Africa
or Europe, then followed the slave
laborators analyzed the otherwise ex-
Chain Letters
There's a
game known
as
tremely stable
"word chains"
genome
trade to the Americas.
Mycobacterium
of
leprae, the microorganism responsible for
in
which you go from one word to another by
leprosy,
changing one
DNA sequence at three widely separated
places in the genome. The DNA "alpha-
letter at a
doe). Geneticists
time
hot, dot,
(fiat,
sometimes see the same
thing happening with
Pasteur Institute
in Paris
of the
and a host of
and discovered variations
in
And
emigration
the eighteenth and nine-
may have brought
M. /eprae to northern North America:
while a leprosy epidemic
in
was taking place
Norway, Scandinavian immigrants were
Midwest and manifesting the
bet" has just four "letters"
settling the
T
disease. {Science 308:1 040-42, 2005)
combinations at those three places
col-
in
teenth centuries
the
—A, C, G, and
—and so the total number of possible
DNA.
Marc Monot and Nadine Honore
from Europe
is
—Stephan Reebs
sixty-
Keeping an Eye Out
Like
most animals, adult
when
giraffes are a watchful crew. But
even
when hungry lions and opportunistic
hyenas may lurk nearby, and even when their own youngsters
could be in danger, giraffes seem more concerned about watching
they're alone, even
one another than watching out
A
recent field study
for predators.
South Africa's Kruger National Park by
in
two biologists, Elissa Z. Cameron of the University of
Nevada-Reno and Johan T. du Toit of the University of Pretoria
South Africa, suggests that when giraffes periodically interrupt
in
their lunch to scan their surroundings, they're mostly monitoring
the whereabouts of the
males are both more
local
male
vigilant
when
Animals generally face
sible
giraffes. Small bulls
and
fe-
large bulls are nearby.
a trade-off
between checking
for pos-
predators and spending their time eating. Giraffes face an
out for superior competitors: giraffe fights can be brutal indeed.
additional problem. Individual females are sexually receptive at varying times of year,
and so
lusty
males are continually on the lookout
for a willing partner. But the males' attentions can interrupt the
all-
important business of eating enough greenery to get through the
day. Receptive females, say the biologists, are probably
lookout for approaching males so that they can
being pestered.
12
And
NATURAL HISTORY
on the
move away before
the younger, smaller males need to watch
July/August 2005
It
also turns out that the giraffe's long neck can
than help.
A giraffe
holding
its
neck
branches of a tree ends up looking at the
neighbors are up
to.
So
it,
sky,
and
its
the uppermost
can't see
too, frequently interrupts
spends more time scanning
giraffes that are feeding
be more hindrance
vertically to reach
its
what
its
feeding and
surroundings than do neighboring
on the middle branches. [Animal Behaviour
doi:10.1016/j.anbehav.2004.08.015, 2005)
—Nick
W. Atkinson
Growing
One must
suffer to
the French. So
all
it is
Shakers and
Strains
become
Movers
beautiful, say
with the rose. IVIaking
those gorgeous colors and alluring
scents does take
its toll.
Eggs, whether from amphibians, birds,
According to
Alexander Vainstein and Mery Dafnymolecular biologists at the
Yellin,
University of Jerusalem,
and
Hebrew
no parent
a fair share
in
,
of which are devoted to fighting stress.
As the petals emerge from
tective covering, the sepals,
in sight, it's
a
glued to a
a
above
leaf
likely
is
pond. But as
a tropical
snake chomps
clutch, breakfast
into
breakfast time! Case
mass of red-eyed treefrog eggs
point: a
soon as
their pro-
and turn
own,
predator chances on a clutch of eggs with
their collab-
thousand different proteins,
in-
their
and few carry noxious chemicals. So when
orators, each rose petal produces almost
a
move on
cannot
sects, or reptiles,
down on
that
to change from
lav-
Sunday brunch to basic continental.
ish
Karen M. Warkentin, a biologist at Boston
a full-fledged but still-closed flower, they
University, has discovered that
embryos are
the
in
opment, a predator attack on
clutch leads to quick
bryos wriggle
group
if
the frog
of their devel-
final third
their
action.
egg
The em-
break out of the
frantically,
capsule that detains them, and drop into the
water below. Because the escapees are not
yet
fully
developed, they may soon
to other predators
i
viva!
is
fall
prey
— but any chance of sur-
better than certain demise
then mimicking the shaking of an egg clutch
the gut
in
It's
under attack by
shown how
of the snake.
What
As a snake shakes a mass of frog eggs, an
embryo escapes and hatches (center right).
triggers the embryos' response?
the
few
first
bites.
acquire their familiar color, and treble or
be frogs react by hatching
two days earlier than their
quadruple their weight. Subsequent
seven-day
stint
on the
leaf.
a
telltale signs of
Warkentin has
embryos can
distinguish
an important predator
from the tremors caused by innocuous
the precise pattern of vibrations caused
by the snake's
a snake,
well the
The soon-to-
day or even
dis-
— and how well-devel-
turbances such as
rain
oped an embryo's
decision making can be.
{Animal Behaviour doi:1 0.1 01 6/j.anbehav.
usual six- to
By recording and
—S.R.
2004.09.019,2005)
growth, and the opening of the flower,
comes from the very
rapid expansion of
already existing cells
in
the petals, rather
than from the addition of
study the process
in detail,
tors divided flower
three stages
new
cells.
the investiga-
development
into
fully
— and analyzed how much of
at
sulfur isotopes in the vermillion
serve as indelible "birthmarks." Then they
For millennia, the vivid orange-red
called Vermillion has
each
Recently a
team
ogists, led
by Takeshi
mental chemist
compared those isotope
decorated
tios in vermillion
of geologists and archaeolIVIinami,
an environ-
at Kinki University in
Japan, traced large quantities of the prized
same
pigment found
flowering process, though perhaps
burial
in
mounds
in
some
central
Japanese
to their source: local mines
Instead, they found that only about
40
percent of the proteins were present at
every stage. Almost 30 percent
a single-stage appearance,
made just
and then were
ished early
in
the
first
millennium a.d.
Yamato
them were not
in-
and that most of
only present at every
stage but also increased
in
quantity as
the flower matured. (P/anta doi:10.1007/
S00425-005-1512-X, 2005)
common
find the source of the central
litical
in
China
Japanese Ver-
and thus help trace the region's po-
history,
sulfur-34; vermillion
in
is
in
far richer in sulfur-
32. Correlating the ratios
showed
vermillion in the western
Japanese
originated
in
in
from
and around
that the
burial
China, whereas the
the central Japanese
—datable to the time of the Yamato kingdom —was
mounds
realpolitik.
Funerary uses of Vermillion, a form of
million,
Guizhou province, China.
the Yamato kingdom,
vermillion
of
in
high
mines may have been an important element
percent of the rose's proteins were
fighting stress,
is
mounds
before they spread to western Japan. To
in
found,
central Japan. Controlling access to those
mercuric sulfide, were
volved
in
in
What a lot of change for a romantic
emblem to endure! No wonder nearly 20
gone.
mine
Vermillion from the Chinese mine, they
the central Japanese mines,
the ancient Yamato kingdom, which flour-
varying quantities.
ratios with the ra-
from three central Japan-
ese mines, as well as from an important ancient
Osaka,
stage. They expected essentially the
proteins to persist throughout the
from
twelve ancient mounds, because the ratios
pottery and preserved royal bones.
tightly closed bud, fully
each kind of protein was present
Red Power
pigment
—
colored but loosely closed flower,
open flower
To
the investigators measured
the relative abundances, or
ratios, of
two
local.
One way the Yamato
with neighbors
was to
clan built alliances
distribute their stash
of Chinese bronze mirrors. Handing out
cally
mined
lo-
vermillion, say the investigators,
may have been
another. {Ceoarchaeology
20:79-84, 2005)
—Caitlin
E.
Cox
—S.R.
July/August 2005
NATURAL HISTORY
13
SAMPLINGS
Play Ball!
summer
All
not see a difference
ond
be wait-
long, kids will
grid
the sec-
until
moved more than
twice
ing eagerly to catch balls tossed
that fast; the adults required a
by Dad or Grandma. And more
speed-up of only one-third.
than
likely,
But
they're going to wait
an easy catch,
will
make
reverse of easy.
A
parents
now shown that
kindergarteners
both groups saw the difference
much more readily. The kids became accurate when the second grid
moved just 44 percent faster than the first grid; the adults were accu-
—and their
—can much more readily assess the speed of faster-moving
rate with a
objects than that of slower ones.
McMaster
Terri L. Lewis, a neuroscientist at
Ontario; Iram
in
J.
Ahmed, now
University
in
age twenty) on speed assessment. Each subject was
asked to watch two grids of identical stripes, both shown moving
across a computer monitor, and to say which was moving faster.
moved
slowly, at
1 .5
about the neurons
it's all
in
the
middle temporal area of the brain. Few of them specialize in responding to dawdlers, and those few take many years to mature.
a medical student at Queen's University
Kingston, Ontario; and their colleagues tested five-year-olds and
"reference grid"
speed-up of just 13 percent.
According to the investigators,
Hamilton,
In
adults (average
When the
sped
at twenty-four feet a second),
group of Cana-
dian investigators has
grid
(equivalent to a ball approaching
a slow
be just the
toss that turns out to
when the first
along at six degrees a second
too long: the grown-up, intending
any event, being better
ness was a useful
bit
at noticing
easier for our ancestors to close
ing across the savannah.
degrees a second
on
in
human
making
race,
it
a four-legged dinner sprint-
So go ahead, put some heat on that bail!
—Elizabeth M. Donohue
45:2129-35, 20
(Vis/on Research
(equivalent to a ball approaching at six feet a second), the kids could
speed than noticing slow-
of evolution for the
By Any Means
Available
Sex
in
the microbial realm
expect, not quite the
people
like
to do
in
is,
same
as
you might
thing as what
their spare time. But
it
does take place.
The fungus Cryptococcus neoformans,
two "sexes" (more techni-
for instance, has
cally,
to
mating types): alpha and
new
research by Xiaorong
ologist at
Duke
University
in
According
a.
Lin, a
microbi-
Durham, and
her colleagues, the alpha type swings both
ways:
it
can exchange genetic material not
only with a individuals but also with other
Hockey
Air
The Heart Mountain
ern
Wyoming
is
rockslide
northwest-
in
the world's largest rockslide
and one of geology's biggest puzzles. What
could cause a mass of rock nearly 450 square
miles
in area,
and weighing
trillions
to slide along a stretch of nearly
and end up,
in
Two
Franklin
of tons,
flat
ground
a matter of minutes, as a
sheet of rubble covering about
miles?
geologists,
Edward
and Marshall College
Pennsylvania, and Gregory
P.
1
,300 square
C. Beutner of
in
Lancaster,
Gerbi of the
Massachusetts Institute of Technology, have
a theory: the slide
was
a gas.
Beutner and Gerbi examined an unusual
layer of rock
known
as a microbreccia, lying
glass.
are
The
much
1997
grains, the investigators point out,
like
the ones that often form
in
gas
The two processes are
—
with just one copy of each chro-
cells (cells
mosome), and meiosis,
of fragments carried
in
a
slid
48
When you add
examined sexual
pressure generated by the friction of the
tion),
slide
moving mass caused the limestone below
it
C. neoformans's
flexibility
a lot of potential to
ca-
adapt to
dioxide gas that floated the rubble. Relieved of the ordinary friction of rock on
gus (most
rock, the slide could
have traveled extraor-
likely, its
goencephalitis
in
spores) causes menin-
people whose immune
systems can't put up
434:1017-21,2005)
July/August 2005
newly
known
new conditions as well as to multiply rapidly. And that's bad news, because this fun-
to break down, releasing a cloud of carbon
{GSA
NATURAL HISTORY
its
you're looking at populations of or-
ganisms with
rocks broke free and
That layer holds
to
pacity for cloning itself (asexual reproduc-
dinary distances at a hundred miles an hour.
slid.
of which are hall-
both produce spores.
million years ago.
was probably triggered by a
nearby volcanic eruption. Then the heat and
The
all
marks of sexual reproduction. Furthermore,
gaseous
cushion that "greased" the surface along
which the rocks
^the
require pheromones, the fusion of haploid
ner and Gerbi say the microbreccia layer
made
al-
—
same-sex one requires the formation of a
which is inefficient but both
clouds released by volcanic eruptions. Beutis
different
fruiting body,
along the fault on which the Heart Mountain
minute grains of carbonate rock and volcanic
14
Yoju, Heart Mountain.
for Giants
phas.
Bulletin
117:724-35, 2005)
— Dave Forest
a fight.
{Nature
—S.R.
CAMBRIDGE
A Landmark Contribution. ^.
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and exquisitely
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is
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Bound
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Truly a definitive
-Thomas
1
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old.
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author of For Love of Insects
volution of tbp Insects chronicles,
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Evolution
evolutionari/ history of insects:
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It
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and
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virtually all original.
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more information, please visit us
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UNIVERSITY PRESS
UNIVERSE
Heading Out
—and make
To explore deep space
—
way
spacecraft will need
stops along the
new forms ofpropulsion.
By Neil deGrasse Tyson
Launching
a spacecraft
is
now
Ifa spacecraft can't
a
slow down,
can't
tach the fuel tanks and rocket
and
engineers. Lately, however, engineers
routine feat of engineering. Atboosters, ignite the chemical
fuels,
have been getting clever about fuel-
away it goes.
But today's spacecraft quickly run out of fiiel. In fact, by
no
bit, there's
main tanks
fuel left in
deprived craft. In the case of the Mars
Rovers, their breakneck speed toward
the
Red
Planet was slowed by aero-
braking through the Martian atmosphere. That meant they could land with
the help of nothing
more than
parachutes and airbags.
Today, the biggest challenge
the time a craft exits Earth or-
in aeronautics
its
—which, no longer
weight and
is
to find a Hght-
means of
whose punch per
efficient
needed, have dropped back to
Earth. Only tiny tanks remain,
propulsion,
permitting only mild midcourse corrections. All the
spacecraft can do is coast to its
conventional chemical fuels.
With that challenge met, a
pound
And what
happens
when
greatly exceeds that of
spacecraft could leave the
launchpad with fuel reserves
onboard, and use them much
later. Scientists could think
destination.
it
arrives?
more about
Without the benefit of fill-
celestial objects as
ing stations or sizable tanks of
places to visit than as planetary
spare fuel, the craft cannot be
peep shows.
made
to
Formnately,
slow down, stop,
ity doesn't
speed up, or make serious
changes in direction.
With
its
can only
saUs,
most
and nuclear
The
would
reactors.
efficient engines
from a nuclear reacand
with
antimatter into contact
tap energy
tor by bringing matter
riders can only glance at the
each other, thereby converting
all their mass into propulsion
what
happened with the Pioneer
energy, just as Star Trek's anti-
and Voyager spacecraft in the
1970s and 1980s: they simply
careened from one planet to
the next on their way out of
Poster for
the solar system.
launched
July/August 2005
and our
space with ion thrusters, solar
fly
—
NATURAL HISTORY
for an
robotic surrogates into deep
moons,
by its destination, hke a fastmoving tour bus with no
and the
stops on its itinerary
passing scenery. That's
no
are ready to propel us
choreographed entirely by the gravity fields of
the Sun, the planets, and their
the craft
human ingenu-
often take
answer. Legions of engineers
trajectory
16
it
land anywhere without crashing, which
is not a common objective of aerospace
matter engines did. Some
even dream of traveling faster than the speed of
physicists
Deep Space
in
1998
1
,
a
NASA spacecraft
light,
by somehow tunneling
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Success
through warps in the fabric of space
and time. Star Trek didn't
either: the
warp
drives
niiss that
on
one
the starship
USS Enterprise were what enabled CapKirk and his crew to
tain
during the
TV
cross the galaxy
ergy that accelerates it. Deep Space 1
used electrically charged (ionized)
first
xenon
from
gas as
its
propellant, rather than
the liquid hydrogen-oxygen
burned
age than explosively
October 1998, an
main
manflammable chem-
in the space shuttle's
engines. Ionized gas
commercials.
combo
is
easier to
xenon happens to be a nowhich means it won't corrode
xenon atoms and then
That energy came
ionize the
accelerate them.
electricity, courtesy of the Sun.
For touring the inner solar system,
where Ught from the Sun is strong, the
spacecraft of tomorrow can use solar
—not
arrays
for propulsion
Inhalf-ton spacecraft called Deep Space
launched from Cape Canaveral,
Florida. During its three-year mission,
Deep Space 1 tested a dozen innovative
or otherwise interact chemically with
than four ounces of propellant a day.
most
propulsion
Deep Space Vs foot- wide, drum-shaped
engine accelerated xenon ions across
an electric field to speeds of twentyfive miles per second and spewed them
height of the spacecraft
1
technologies, including
a
system equipped with ion thrusters.
Acceleration can be gradual and
ble gas,
anything. For 16,000 hours, using
less
itself,
but for
power needed to drive the
equipment that manages the propulsion. Deep Space 1 has folding solar
the electric
icals. Plus,
eight-foot-tall,
"wings." Fully extended, they span
—about
forty feet
on them are
lar cells
al-
five times the
itself
The arrays
combination of 3,600 soand more than 700 cylindrical
a
spacecraft off the ground.
on the cells.
At peak power, their collective output was more
than 2,000 watts, enough to
You've got to have
at least
operate only a hair dryer or
many pounds of thrust as
two on Earth but plenty for
powering the spacecraft's
prolonged, or
it
come from a brief,
Only a
can
spectacular blast.
major
as
can propel
blast
the weight of the craft
self.
lenses that focus sunlight
a
it-
ion thrusters.
Otherwise, the thing
willjust sit there
— and
if
last
still
I
on.
Other, more familiar
such as the
After that, if you're not in a
big rush
And
heard, the radio was
on the pad.
spacecraft
you're
—
sending cargo rather than
now-disintegrated Soviet
crew to the distant reaches
of the solar system there's
no need for spectacular ac-
space station Mir and the
—
celeration.
nearly seven-year-old International Space Station
And that's when
ion thrusters
work
(ISS)
—have
on the Sun
best.
also
depended
power
for the
to operate their electron-
lon-thruster engines do
what conventional space-
ics.
A
work-in-progress
engines do: they accel-
orbiting about 250 miles
erate propeUant (in this case,
above Earth, the ISS wiU
eventually carry more than
craft
a gas)
to very high speeds
and channel
it
an acre's worth of solar
of
out a nozzle.
panels. For about a third
In response, the engine, and
every ninety-minute orbit,
thus the rest of the spacecraft, recoils
direction.
in the opposite
You can do
this
science experiment yourself
on
While you're standing
Cosmos
shown here in an artist's conception, is
intended to be the first solar sail placed in orbit around
Earth.
sails
1
Its
,
launch
scheduled for
fire
summer. When all its
be propelled solely by
course, for this purpose).
The
gas will
go one way; you and the skateboard will
go the other way. This equivalence of
action and reaction is a law of the universe, first described by Isaac Newton in
the late seventeenth century.
But ion thrusters and ordinary rockengines part ways in their choice of
propellant and their source of the en-
NATURAL HISTORY
ness.
July/August 2005
So by day, some of the
collected solar energy gets
the pressure of the Sun's rays.
extinguisher (purchased, of
Earth eclipses the Sun,
the station orbits in dark-
this
will
a skateboard, let loose a
CO2
et
is
are fully unfurled, the craft
as
channeled into storage batduring dark hours.
Although neither Deep Space 1 nor
As anticipated, the recoil per pound of fuel was ten times
greater than that of conventional
teries for later use
rocket engines.
self,
from
its
nozzle.
the ISS uses the Sun's rays to propel
direct solar propulsion
is
impossible. Consider Cosmos
In
space, as
thing
on Earth, there
as a free
lunch
is
—not
no such
to
men-
Something had to
power those ion thrusters on Deep Space
tion a free launch.
1
.
Some
investment of energy had to
gineless,
220-pound
far
1,
it-
from
an en-
spacecraft that
will be propelled (once it achieves
Earth orbit) solely by the pressure of
sunlight. In fact.
By
the time
Cosmos
? is
a solar
sail.
you read these words,
it
may
have entered
its
intended
initial
500 miles above Earth. The project is a privately funded collaboration
between U.S. and Russian space scientists, led by The Planetary Society.
This summer's launch will culminate
nearly five years of work by rocket sciorbit,
who would
entists
rather collaborate
than contribute to mutual assured
destruction (aptly
Shaped
known
MAD).
as
an un-
armed
left
intercontinental ballistic missile
over from the Soviet Union's cold
war arsenal, and then launches from a
Russian submarine. Cosmos 1 has a
computer at its center and eight reflective, triangular sail blades made of
Mylar reinforced with aluminum.
could help
fifty feet
thick
trash
yet
only 0.0002 inch
is
—much thinner than
—and can be
bag
gled to steer and
o
a
cheap
individually an-
sail
the
along with a
it
from Earth, or with
a
is
you
beamed
feeble,
laser,
network of lasers
^Evolution
Speaking of regions where the Sun
IS dim, suppose you wanted to park a
space station in the outer solar sys-
—
at Jupiter, for instance,
sunlight
IS
is
only 1/27
where
intense as
as
.Human
it
here on Earth. If your Jovian space
station required the
solar
power
tional
same amount of
the completed Interna-
as
Space Station
will,
your panels
would have to cover twenty-seven
acres. So you would now be laying
solar arrays over
twenty football
'4'\
an area bigger than
Fuggedaboutit.
fields.
To do complex science
in
deep
space, to enable explorers (or settlers)
to
spend time
ment on
there, to operate equip-
the surfaces of distant planets,
you must draw energy from sources
craft.
aloft,
the solar
erate because
sail
will accel-
of the continual,
its
bouncing off the reflective
As they bounce, the photons
blades and
surfaces.
will give rise to a gazilHon
little
recoils
No fuel. No
No mess. You
in the opposite direction.
fuel tanks.
No
Since the early 1960s, space vehicles
of the Sun's gaziUion
photons, or particles of Ught, hitting
exhaust.
can't get greener than that.
Having entered
space, a lightweight
have
commonly
relied
on the heat
from radioactive plutonium as a power supply. Several of the Apollo missions to the Moon, Pioneer 10 and 11
(now more than 8 biUion miles from
Earth, and headed for interstellar
space). Viking 1 and 2 (to Mars), Voyager 1 and 2 (also destined for interstellar
space and, in the case of Voyager
of years,
accelerate to 100,000 miles an hour.
Such a craft escapes from Earth orbit
(where it was deposited by conventional rockets) not by aiming for a
others, have
destination but by cleverly angling
inefficient but long-lasting source
solar sail could, after a couple
blades, as does a sailor
on
its
a ship, so that
ascends to ever-larger orbits around
1,
farther along than the Pioneers),
Cassini
(now orbiting
all
Saturn),
and
among
used plutonium for
their radioisotope thermoelectric
generators, or
RTGs. An
nuclear power.
and
RTG
Much more
much more
energetic,
is
an
of
efficient,
would be
a
orbit could be-
nuclear reactor that could supply both
of the Moon, or
the transportation of choice if you're
power and propulsion.
Nuclear power in any form, of
course, is anathema to some people.
Good reasons for this view are not hard
in a hurry to receive supplies, but
it
to find. Inadequately shielded pluto-
would certainly be fuel efficient. If you
wanted to use it as, say, a low-cost fooddehvery van, you could load it up with
pose great danger; uncontrolled nu-
Earth. Eventually
come
^
other than the Sun.
nee
collective thrust
it
Woj^ldof:
stationed across the solar system.
When unfurled in space, each blade extends
^^GofTTiplete
And as the craft sailed into sec-
where the Sun's hght
tors
tem
like a supersize daisy, this
celestial sailboat folds inside
other edible items of extremely high
shelf hfe.
the same
its
as that
Mars, or something beyond.
Obviously
a solar sail
would not be
freeze-dried veggies, ready-to-eat
breakfast cereals. Cool Whip, and
nium and other
radioactive elements
clear chain reactions pose an even
up
a
list
And
easy to
draw
of proven and potential
disas-
greater danger.
it's
"^J^
Thames & Hudson
Available wherever books are sold
thamesandhudsonusa.com
ters:
the radioactive debris spread
Canada
1978 by
the crash of the nuclear-powered Soviet sateUite Cosmos 954; the partial
meltdown in 1979 at the Three Mile
Island nuclear power plant on the Susquehanna River near Harrisburg,
across northern
in
Pennsylvania; the explosion at the
Chernobyl nuclear power plant in
1986
in
tonium
what
is
in old
now Ukraine;
the plu-
RTGs currently lying in
(and occasionally stolen from) remote,
decrepit Hghthouses in northwestern
Russia.
The
list is
long. Citizens' or-
ganizations such as the Global Net-
work Against Weapons and Nuclear
Power in Space remember these and
other similar events.
needs of a small school
SUV. To
But
scientists
—or
a single
Promethean ad-
tions
Orbiter, or JIMO.
would be
—
Callisto,
Its
From
of ice may
he vast reservoirs of hquid water that
harbor, or once harbored, hfe.
Endow^ed with ample onboard
JIMO would do a "flyto,"
rather than a flyby, ofJupiter. It would
puU into orbit and systematically visit
propulsion,
time, perhaps even de-
ploying landers. Powered by ample
onboard
electricity, suites
of scientific
instruments would study the
moons
the Earth to the
My
that beneath their thick crust
at a
is
efficient:
he antimatter drive. Put antimatter
nd matter
together,
puff of pure
Rather than deny the risks ot nuclear
devices,
NASA has turned its attention
maximizing safeguards. In 2003 the
agency charged Project Prometheus
with developing a small nuclear reactor that could be safely launched and
could power long and ambitious missions to the outer solar system. Such a
reactor would provide onboard power
and could drive an electric engine with
the same kind of
ion thrusters
propulsion tested in Deep Space 1.
To appreciate the advance of technology, consider the power output of
the RTGs that drove the experiments
on the Vikings and Voyagers. They supplied no more than a hundred watts,
about what your desk lamp uses. The
RTGs on Cassini do a bit better: they
could power your thousand-watt
microwave oven. The nuclear reactor
to
—
that will
emerge from Prometheus
as much as 200,000 watts
of power, equivalent to the energy
should yield
20
NATURAL HISTORY
July/August 2005
and they turn
into
energy.
and send data back to Earth via highspeed, broadband channels. Besides
efficiency, a big attraction would be
safety, both structural and operational.
The spacecraft would be launched
with ordinary rockets, and its nuclear
reactor would be launched "cold"
not until JIMO had reached escape velocity and was well out of Earth orbit
would the reactor be turned on. As of
this writing,
however, plans for JIMO
on hold: a series of simpler missions
wiU more expeditiously test the new
Promethean propulsion systems.
are
put
a
together with a
It's
100 percent
pound of antimatter
pound of matter, and
they turn into a puff" of pure energy,
with no by-products. Antimatter is
real. Credit the twentieth-century
British physicist Paul
A.M. Dirac
for
m
conceiving of it
1928, and the
American physicist Carl D. Anderson
for discovering
it
five years later.
science part of antimatter is fine.
the science-fiction part that presents
It's
science-jiction engine is
favorite science-fiction engine
the antimatter drive.
The
dy favorite
tales as
is
and Europa three of the four moons
of Jupiter discovered by Galileo
1610. (The fourth, lo, is studded with
volcanoes and is flaming hot.) The lure
moon
came from such
have read enough science fiction in
one's hfetime, it's also possible to have
read too much of it.
destina-
Ganymede,
of the three frigid Galilean moons
inspiration
m
has been proposed: the Jupiter Icy
Moons
luminal quantum phenomena. Their
Moon, by Jules
Verne, and the adventures of Buck
Rogers, Flash Gordon, and Star Trek.
It's okay to think about this sort of
thing from time to time. But, in my
opinion, though it's possible not to
vance, an ambitious scientific mission
one
do the
and engineers who work on NASA's Project Prometheus.
so
exploit the
problem. How do you store the
Behind whose spaceship cabin or
under whose bunk bed would the canister of antimatter be kept? And what
substance would the canister be made
of? Antimatter and matter annihilate
each other on contact, so keeping antimatter around requires portable matterless containers, such as magnetic
a small
stuff?
fields shaped into magnetic botdes. UnUke the fringe propulsion ideas, where
engineering chases the bleeding edge ot
physics, the antimatter problem is ordi-
nary physics chasing the bleeding edge
of engineering.
So the quest continues. Meanwhile,
next time you're watching a movie in
which a captured spy is being questioned, think about
this:
The ques-
tioners hardly ever ask about agricultural secrets
or troop movements.
With
an eye to the future, the)- ask about the
Someday
there might be wackier
ways to explore within and beyond our solar system. The folks at
NASA's now-defunct Breakthrough
Propulsion Physics Project, for instance, were dreaming of how to couple gravity and electromagnetism, or
tap the zero-point energy states of the
quantum vacuum, or harness super-
secret rocket formula, the transporta-
tion ticket to the final frontier.
[This
is
part two of a two-part
Astrophysicist Neil deGnissc Tyson
rector
ican
article.]
is
the di-
of the Haydcii Plauetiniiim at the Amer-
Museum
of Natural History. His
latest
Donald Goldsmith, is
Origins: Fourteen Billion Years of Cosmic
Evolution (U:u: Norton, 2004).
book, co-aiithored with
OTi
rj^^^^-
'»S'(to-;%'!5T"
ax
When
quality isn't enough to take on the big guys.
The fine horologists (watchmakers) at
Stiihrling just built a super luxury
watch
for this Christmas. Using one of
the most complex regulator move-
ments ever designed, they engineered
3. With it's large
separate minute dial and small hour
dial, this watch was built to
the Regulator Series
take
on the
Phillipe^"
to
for
Max made
quality watches at extraordinary values.
We
are offering the Regulator for
a miraculous price
by
Well,
to
The
other luxury watch manufacturers had locked up the
shelf space at the high end
jewelers by offering large
Max
is
of
these
contracts,
left
so
with 3,435
magnificent
"Regulator Series 3" watches.
Max
needs to liquidate
these luxury watches so he
came to us at NextTen. You
see, NextTen has become
synonymous with high
For
collectors
in
after
years
in
it
special?
The
Regulator
make you want to
how
to
tell
time
will
learn
over
all
The Regulator
movement is utilized in
again.
A back
as beautiful
as the front
The
unique
bronze-
master
the
Stiihrling
can watch the smooth
ment
for
movement of the rotor
and the 22 jewels work
Series
3.
in precise
harmony.
24 hours
a
clocks
ized this
has miniatur-
complex movethe
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Separate
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make you stare at
day
at
but
observatories,
finished movement is
absohitely stunning. You
unique watch. The
a
silver-white
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line
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machined in
and the
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oscillates
at
21,600 vibrations per hour for accuracy to within seconds per day. The tonneau styled case is fused in 23k gold
and the alligator-embossed band
is fit-
ted with the finest butterfly clasp that
seen in our travels.
desire the best, the
If
you
unique and the
the Stiihrling Regulator is built
We do expect to be out of this
watch in just a few weeks, so please
rare,
for you.
act quickly.
Watch
5 Payments of 569." +S&H
Promotional Code SRW161-01
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Please mention this
when you
To order by mail, please
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neXtten
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this
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us online at wtvtv.NextTen.com for the complete
dial
star
escapement is visible through the dial
so you can watch the balance wheel in
we have
come.
What makes
fastest sei-vice, call toll-free
Visit
is
make
watch sought
this
a mistake.
advertising
Max
the rare design will
and was
$5,750.
— $349.^5
but he needs the cash. When the
3,435 watches are sold, that will be the
end of them. 1 am keeping three for
myself since I'm convinced that
tears,
likes of Rolex"^"
and Patek
retail
mistake
Stiihrling's big
Minnesota 55337
I
of Watches, Jewelry
and
Collectible
NATURALISTS AT LARGE
the inid-l 990s.
Comeback Kids
When we arrived in the
park, in the middle of this devastating
period, the
Zambian government sim-
ply did not have the resources to stem
the onslaught.
moms"
Elephant "single
Part of the
are struggling to recreate
mote
family
life
after the traumatic years
of poaching.
problem was the park's reIt is nesded under the
wilderness.
shoulder of the Muchinga Escarpment,
where
waterfalls
tumble
over forested mountains
By Delia and Mark Owens
She
Thereus—bybaby!
the
a
is
coming
river," Patrick
to
Mwamba,
a
Bemba
tribes-
man, whispered. Across the river from
our camp a small female elephant trotted along the shore, her trunk flopping
loosely like
a garden hose. Abruptly,
she stopped and looked into the
grass,
south.
then turned and walked slowly
Holding her httle trunk in the
air like a
periscope, she twisted the end
around in
22
tall
all
directions.
NATURAL HISTORY
July/August 2005
As we watched
her, Patrick
whis-
pered what each of us was thinking:
"She is very much alone in this place."
Another orphan. They had become
commonplace here, in North Luangwa National Park (NLNP), Zambia.
From the late 1970s through the 1980s,
commercial poachers had shot 93 percent of the elephants in the population
for their ivory, skin, or meat. The population had declined from 1 7,000 in the
mid-1970s to approximately 1,500 by
a
thousand
[see
feet
map on
op-
To the east ofthe mountains,
the wide Luangwa River snakes its way
through a valley, creating enormous
floodplains and habitat for Cape buffalo, Cookson's wildebeest, puku ante-
posite page].
lope,
and
zebras. In 1986, gliding over
the plains for the
first
down from our small
rime and peering
airplane,
we saw a
landscape that looked wild and
fact,
though, poachers had taken
free.
it
In
over.
Bands of as many as a hundred men had
set up makeshift encampments, from
which they would sally forth to shoot
elephants and lions. Then, like scurry-
ing
they
ants,
would
carry the illegal
sums ofmoney from ivory, so they
large
ivory and meat over the escarpment,
could no longer afford to hire
where
be shooters or porters.
poaching declined to
fewer than ten elephants killed in 1 99 1
and even fewer per year in the next
decade. Still, a few elephants were being shot. The entire family of the orphan that Patrick spotted had been
mowed down with machine guns, before she made her way to our camp.
it
was sold to smugglers.
For more than 200
years, the
to
high
value of ivory and other elephant products have
villagers
made hunting and poaching
ongoing facts of Hfe for elephants, both
in Africa and in Asia. The easiest way
to get the ivory has always been to kill
the giant creatures, and as firearms have
become more common, more accurate, and more deadly in the past two
centuries, more elephants have been
killed. The elephants ot Luangwa were,
to some extent, protected by their remote location and by the ruggedness of
Finally the
throughout their
unit
as
and each family
days before widespread poaching, could
be
live to
ers,
sixty years old.
mothers, aunts,
Grandmoth-
sisters,
and female
romp
cousins feed together,
in the
and play on the plains. There is a
lot of touching and bumping of body
parts, and the animals, like afiectionate
rivers,
show very
tanks,
ward each
little
aggression to-
other.
Young males
and the two of us watched
she slowly dropped her trunk.
Patrick
lives,
led by a matriarch that, in the
is
stay in the
which they were born
group into
until they reach
puberty (nine to fourteen years ot age)
Since they are related to every female
in their natal family unit,
when
testos-
the terrain. In the early years of the
terone kicks
ivory trade they had fewer losses than
of the unit in search of a suitable mate.
Adult males spend much of their time
alone, or with several other males that
stay together while feeding. When a receptive female comes along, however,
It's every bull for himself
Young females learn a great deal
did elephants in other,
more densely
human-inhabited areas, such as South
But by the late 1970s, intense
poaching finally reached NLNP. There
were stiU 5,000 elephants in the park
when we arrived in 1986, but the
poachers were .shooting about a thouAfrica.
about maternal behavior from their
sand every year.
to
Working
with the Zambian National Parks and WildUfe Ser-
North Luangwa Conservation Project
(NLCP), which offered alternative
and conservation education. Poaching is not only illegal, it is dangerous and not very prof-
jobs, rural health care,
itable for the vUlagers. Ivory
smugglers
paid vUlagers only ten dollars for shoot-
ing an elephant.
With
in place,
the village jobs
many of the former
poachers and other villagers became
beekeepers, fish farmers, millers, or
sunflower-press operators.
Men
and
reproduce or
lactate,
are old
el-
enough
female adoles-
cents "practice" the art of nursing infants
vices
program
Long before they
ders.
and the Anticorruption Commission, we assisted government game
scouts by providing housing, trucks,
uniforms, and food for their patrols.
With new training and incentives, the
scouts began capturing poachers.
But even more important, in fourteen outlying villages we set up the
they leave the security
in,
for a
by putting one forefoot forward;
mother and her calf that move-
ment
gives the calf easier access to
teats. If any
North Luangwa National Park, where the
mother's
authors have studied the effects of poaching
ily squeals, all
on elephant populations, lies in northeastern
Zambia. The park is approximately the size of
aid
the state of Delaware.
walked into the
peared.
We
tall
grass,
and disap-
crossed the shallow river,
camp.
ing
pulling
it
We
studied the foot-
prints the Httle elephant
had
left in
the
the ancient routes across the mountains
for the best dry-season forage.
international ivory ban, adopted in
whose gene Unes
1989. Smugglers could no longer make
tions.
old.
We named her Gift;
didn't expect to see her again.
African elephants usually
social
groups
—
live in tight
in fact, family units
persist for
genera-
Females remain within the group
They
lead the other elephants across the
angwa River
Lu-
in darkness to avoid the
The
ly together,
we
They know
the water sources in times of drought,
mate their ages by measuring the length
of their hind footprints. The method is
particularly accurate up to fifteen years
of age, and so we were fairly certain from
our measurements that the orphan was
about five years
its
out of the mud, push-
old matriarchs are the group's
poachers.
and supported their families.
Another tool that proved essential in
the struggle against poaching was the
the females run to
storehouses of knowledge.
white-hot sand. African elephants grow
throughout their lives, so one can esti-
women had safe, profitable jobs that fed
it
its
fam-
up an embankment.
The
keeping an eye out for Ripples, a crocodile that frequented the pools and eddies near
—
infant in the
matriarch's guidance
is
the glue that holds the elephant fami-
social
making it among the most
and cooperative groups of ani-
mals on Earth.
But Uttle Gift was alone. She was obweaned or she would not have
survived, but she had no family members to touch her, to lead her, or teach
her the ways of the elephant world.
The next day Camp Group a loose
alliance of males that often visited our
camp to eat the crab-apple-Uke maruviously
—
July/August 2005
NATURAL HISTORY 23
—
wandered across the river and
on the tall grass by our cottage.
Forty yards behind them was the
diminutive Gift. Abandoning all nor-
age structure
Almost three years after we first saw
been heavily skewed: only 6
percent of the population was older than
twenty. Before the most recent fifteenyear stretch of severe poaching, more
our cottage and knocked on
the door. "Come see," he said. "The
baby elephant, the one you call 'Gif-
than half the elephants in a neighboring
tee,'
population had been older than twenty.
"What! That's impossible." Gift
could not be more than eight and a half
la fruit
dividuals to only five.
fed
had
mal elephant behavior in the absence
of a female family, Gift had taken up
residency with the Camp Group males.
Almost every day we could see her
feeding near them.
Now
and then Gift would walk up
to Survivor, the first male to accept our
presence after poaching was reduced,
or to Long Tail, another male in Camp
Group, whose tail was so long it almost
touched the ground. She would hold
up her toy-size trunk to theirs in
greeting. But the males ignored
her; after all, she was much too
young for breeding. In our experience, females did not ovulate before the age of eleven, and usually not until age fourteen.
In
The
fact,
of reaching out
a
females between twenty and
had been the most
members of populations in which poaching was not severe. Now very few females in that age
group in the NLNP remained aHve.
No longer were massive and wise old
ing foreheads,
as
aunts would have
which females usually gave birth.
But sure enough, we found Gift with
a small, dark-gray infant at her side. At
matriarchs leading the family units.
first
A
its
fects
named her
We
fitted radio collars
come
ily units
Georgia, shares a
her mother,
North Luangwa National Park.
in
cfrinfc
Gift,
an
orphan elephant, became a "single mom" at the age of
eight. Because of poaching, a quarter of the family
units in the park include just a mother and a single calf.
Before poaching became common, Gift and Georgia
would have had calf-rearing help from a group of
of the most striking effects of
poaching we documented was that by
the 1990s, 38 percent of the NLNP elephants were tuskless. In elephant populations where poaching had not been
a problem, approximately 2 percent of
percent of the groups were
entirely of orphans.
made up
Young
males,
elephants had
which, in an undisturbed elephant
society, would still be living in their
mothers' groups, formed groups of their
own. They reminded us of inner-city
gangs, chasing nonreceptive females and
ers
fighting
no tusks. Because poachhad obviously selected individuals
for their tusks, the percentage of the elephants remaining without tusks had
greatly increased.
But it was not just the number of elephants or the presence of tusks that had
changed with poaching. Their very social structure was being transformed.
The average size of the family unit had
from eight in-
July/August 2005
moms
among themselves. The NLNP
elephant population had essentially
been reduced to groups of teenagers.
But the makeup of the groups also
posed a mystery. Many of the family
units had more infants than adult females. Elephants do not normally adopt
orphans, so how was such a shift possible? It
would
that question.
take us years to unravel
now one-quarter
of the elephant families in North
Luangwa were made up of just a
at a river with
Gift's first calf
female older than fifteen years. Eight
NATURAL HISTORY
had be-
Single
of two elephants made up
data told us that
One
24
a half, Gift
mom.
only 3 percent of the total. But our
population.
in half;
a single
unheard of in normal
elephant populations. Before the
severe poaching in Luangwa, fam-
on one female in each of sixteen family
female relatives; now, they are on their own.
units, and measured the footprints
ofmost ofthe remaining elephants,
third of the units included no adult
thereby determining the ages of the
been cut almost
Georgia.
are almost
Gift, the
elephant population.
might be another
it
At eight and
bump-
of the severe poaching on
NLNP
thought
own, but looking to Gift for security. But we soon saw the Httle female nursing and knew for sure
that it was Gift's daughter. We
males turned their backs to her.
the
we
at
orphan, clearly too small to survive on
They
For ten years we studied the ef-
She was only half the age
years old.
reproducrively active
her mother or
done to
has got a baby."
forty-five years old
So instead
trunk or
walked
softly to
never gave birth before age sixteen. Gift was only five.
Mwamba
Gift, Patrick
also
single
mother and her
first calf.
Of course, the infants born to
single moms were not surrounded by grandmothers, aunts, female
cousins,
and
sisters.
in East Africa have
that in
Investigators
determined
normal unstressed, un-
poached populations of elephants, aUomothering care given by female relagreatly
tives other than the mother
enhances the survival of a call. Other
females of the family group even help
remove the birth sac from newborns.
But Georgia had no one but Gift.
What was most amazing to us, however, was that Gift had given birth at
such a young age. We thought that perhaps she was a fluke. Because she was
an orphan, and because she hung out
with males all the time, never with
adult females, she had become pregnant against all odds. But at least it gave
—
—
us a
good opportunity
to observe the
maternal behavior of an orphan.
By that time. Gift had accepted us
completely, and so Georgia did, too.
Her newborn wobbling
at
her heels,
walked down the paths in our
camp; they looked more like two small
sisters than mother and offspring.
Gift
Gift was not a good mother For one
thing, of course, she
was very
young. But since she had not been raised
in a family unit, she also had no experience with the frequent touching and
gentle care that are part of normal elephant social life. Gift rarely reached her
trunk to her calf and sometimes hard-
seemed to notice
weeks of life, a calf
ly
her. hi the first
stays close to
its
mother, sometimes leaning against her
were a tree trunk.
tew months old, it begins
large leg as if it
it is
a
Meanwhile NLCP, our
project to
had grown. We
were now ofiering aid and education
to approximately 20,000 Zambians in
remote villages near the park. And to
our great reUef, in 1996, we recorded
no elephants shot in NLNP.
But because the North Luangwa
elephants had been harassed and killed
for so long, many of them were stiU
wary of people. The best way to observe them was from the heUcopter
purchased by the NLCP. Two or three
times a week we took off in the chopper and soared over the radio-coUared
assist villagers,
elephants
as
they
moved
over the lush
We
When
plains or riverine forests.
to ex-
high enough to keep from disturbing
stayed
cousins to
assist
with the squealing in-
no sisters to help protect their offspring. Our aerial counts showed that
even though the poaching had stopped,
the elephant density was not increasing, possibly on account of high calf
mortality and the protracted reproducfants,
tive cycle. It will
years for the
many
probably take
numbers
to recover.
the time Gift was sixteen years
By —
old
an age when, under normal
circumstances, she
would have been
giving birth to her
first
three calves of her
calf.
The
—she had
calf
own and one grand-
grandcalf (Georgia's calf)
eventually died, but this small family
unit,
founded by an "ivory orphan,"
Poaching has cut the average size of the elephant family unit in half
plore farther away, but if it strays too
far,
mother or another female will follow it. Not so with Gift and Georgia.
One morning when Gift was feeding on marula fruits in camp, Georgia,
now about three months old, wandered
away from her mother. Gift walked
quickly and silently in the opposite direction, toward some large marula trees
about forty yards away. Moving her
trunk along the ground like a vacuum
the
them, and monitored the new infants
born into each family. We also continued to determine the age of the population by measuring footprints. But
we had stiU not solved the mystery of
was making
why
she was
each family unit always included
more
One morning we watched a young
same age as Gift,
newborn. Mark said into
female, about the
the radio intercom, "That's
cleaner, she searched for fruits until she
giving birth so
was out of sight of her calf
Suddenly Georgia looked up and
could not see her mother. SqueaUng
The
loudly she dashed around camp, her ht-
revisited
tle
legs
pumping and her trunk wrig-
gUng. She trotted up to
us, stared at us
young
is
not
it.
Gift
a fluke.
adults are dead, so the adolescents
are giving birth!"
We flew a beeUne back to camp, and
our
data. In
70 percent of the
family units there were not enough
adult females to account for the
num-
few seconds, and then ran toward
ber of infants. But there were plenty of
the office cottage in the opposite di-
adolescent females that could have been
We backed
up so that we could see Gift. The young
mother continued to feed on marula
the mothers.
for a
rection from her mother.
fruits,
cries
completely ignoring the
of her
calf.
shrill
We fought the urge to
chase Georgia toward her mother, for
fear
of making matters worse.
Finally, Gift walked into view and
Georgia saw her. The calf trotted to
her mother's side, and stayed very near
her until they both ambled out of camp
several minutes later.
We
tailed observations
started
making de-
of these family units.
And, sure enough, in the absence of
adults, females in North Luangwa between eight and a half and fourteen
years old were accounting for 48 percent of
all
births.
On
their
small faixdly units of only
own
ation without relatives, without culture,
without
The
infants than adult females.
suckling a
a comeback. Like a single
mother in a disrupted human family,
she was making the best of a bad situ-
or in
two or three
elephants, these "teenage" mothers
were slowly, haltingly fostering the next
generation. They had no old matriarchs
to lead them, almost no aunts or female
still
much social support. But
making
disruption
a
we
go of it.
have seen in ele-
phant social behavior in North Luangwa is mirrored in other populations of
African elephants on the continent.
They too are facing decreased numbers
of matriarchs, the breakdown of family units, and a shift in sex ratio favoring females. But Gift's abiHties as a family leader, which have improved as her
family has grown,
is
her Httle herd's
foothold on the future, and perhaps the
best
hope
for the return
of the great
herds of yesterday.
Mark Owens
Deua
and
research
and established conservation projects on
have conducted
endangered species in Africa for twenty-three
From 1986 until 1997 the Oweuses deLuangwa Consen>ation Proin Zambia, which was financed by the
years.
veloped the North
ject
Owens Foundation for
and
Wildlife Conservation
the Frankfurt Zoological Society. Tlie pro-
ject's pillage
direction
programs continue today under the
of Zambians. The Owenses are the
authors of numerous articles and the best-selling books Cry of the Kalahari and
of the Elephant.
July/August 2005
The Eye
NATURAL HISTORY 25
JULY/AUGUST 2005
Cold
In Antarctica's
Fire
Dy]^^^^
the deep chambers and' conduits
that
poured hot lava onto the surface
are exposed as tiowhere else
on Earth
Edmond A. Mathez
jTSi^
one would think nothing of pouring
Scotch whiskey over a few chunks of ice. But this
ice was more than 18,000 years old! It came from
the Taylor Glacier, an enormous river of ice flowing off
Normally
the polar ice cap into Antarctica's Taylor Valley.
The
wall
of the glacier is marked by a pair of thin, brownish layers
of volcanic ash, each containing mineral grains that have
been dated by radioisotope decay. The lower layer is 18,000
years old, and since our ice came from below it, we knew
er parts
of rock that
—or
!
NATURAL HISTORY
simply, the
July/August 2005
Dry
Valleys.
The
re-
cross the
surrounding strata) and
to the strata). Basalt, a
most
Valleys of Antarctica
among the most wa-
has been studying a labyrinth
For the
of basaltic rock spectacularly exposed in the walls of the Dry
Valleys. The labyrinth is made up of dikes (sheetlike bodies
band of Scotch drinkers included me
and t^venty-four other geologists. At the behest of Bruce
Marsh, a geologist at Johns Hopkins University, and with
the support of the U.S. National Science Foundation, we
had assembled in Wright Valley, one of the McMurdo Dry
deserts,
on Earth.
past decade. Marsh
allel
in this
of the Dry Valleys are
terless places
the ice must be older than that.
The "we"
26
gion IS surely among the most remote, exotic, and starkly
beautiful corners of the planet. In spite of the ice and snowthat blanket the rest of Antarctica, Wright, Taylor, and oth-
common
Earth's
igneous rock on Earth.
upper mande
sUls
(bodies paris
the
when
the
fine-grained black rock,
partially
It
forms
melts, and the resulting mag-
where it can soUdify rapidly, either within
the crust, as dikes and sills, or at the surface, as erupting lava.
The dikes and sills of the Dry Valleys are the remnants
of a kind of plumbing system through which magma
ma
rises to places
worked
its way to the surface in a series of eruptions about
180 milHon years ago. Volcanic plumbing systems are rarely
exposed at the surface. The reason is simply that around
active volcanoes, lava covers everything.
tive
Even
at old, inac-
volcanoes that have been deeply dissected by erosion,
geologists
edifice,
commonly
see only the interior
of the volcanic
not the structure of the rocks below.
Exposed to view in various parts of the Dry Valleys, howis a vertical sUce of the dikes and siUs immediately beneath the lavas, which cuts across layers of rock two and a
see
Hence along the vaUey waUs,
much deeper
almost anywhere
the
geologists can
plumbing than they can
Taken together, the dikes and siUs of
into the volcanic
else.
Dry Valleys are known as the Ferrar dolerites,
ley Ferrar, the geologist
Scott's
who,
as a
after
Hart-
member of Robert
1901—1904 Discovery Expedition,
as
such. Dolerite
is
basaltic
first
F.
recognized
magma that
and dikes near the surface.
The dikes and siUs bear on several questions geologists
soHdifies rapidly in
One
of them
is
sills
why
volcanoes
vai7 so widely in composition
the planet's surface.
commonly
—
a
also
to study the Ferrar
extremely well exposed
composition and
in the valley walls.
assembled a group of geologists,
all
ask.
erupt lavas that
major factor in creating
Marsh had chosen
dolerites because they are quite variable in
ever,
half miles thick.
the valleys' dolerites
Now he had
experts in the physics and
chemistry of magmatic systems, to share insights, help discover the reasons for the compositional
and use the
complex bodies
diversity,
lessons learned in Antarctica to understand
of rock elsewhere in the world.
Sipping Scotch in our isolated camp, though,
we were
by the rocks, but also by the enormous
and ahen nature of our surroundings. The Dry Valleys
fascinated not only
scale
July/August 2005
NATURAL HISTORY 27
150°E
may act somewhat like icy features discovered
on Mars, and the bacteria that occur in the ice and
leys
saline lakes
ists.
So
may resemble extraterrestrial Hfe, if it exmoment to wander through the
let us take a
hyperdry, hypercold landscape.
A
.
nent, with an area far larger
than that of the United States (5.25
million versus 3.5 million square
77.25°S
Obscured by the conti-
miles).
nent's ice cover, the Transantarc-
Mountains divide Antarctica
two parts [see map at left]. The
major part of the continent lies in
the Eastern Hemisphere, on one
side of the mountains, where it is
apparently made up of ancient,
crystalline bedrock. Most of that
tic
into
rock Hes above sea level and
is covered by the East Antarctic Ice
Sheet, a body of some 6 million
cubic miles of
side
On
ice.
of the mountains
is
the other
the
much
smaller (0.8-niiIlion-cubic-mile)
160°E
miles
Shaped like a set of fingers, the Dry Valleys extend toward
the open sea. Only Taylor Valley reaches the sea, however.
The
extreme
consequence of their position flanking the Transantarctic Mountains and the polar
plateau. Cold, dense, dry air masses form on the plateau and
tumble down the valleys with the prevailing wind. As the air
descends, it warms and thereby expands its ability to hold
valleys'
aridity
is
a
moisture, carrying off virtually every bit of water
in its
path.
The Transantarctic Mountains also hold back the seaward
East Antarctic Ice Sheet, keeping the val-
movement of the
leys largely free of ice.
feature rivers that stay
trickles that
saltier
(turn
bone-dry except
flow inland to frozen lakes
summer
many times
for
than seawater; glaciers whose surfaces sublime
from
solid ice directly into
water vapor) but do
reason the valleys exist
Antarctic Ice
ing toward the
At the
sea.
temminus four degrees Fahrenheit (minus
twenty degrees Celsius), and the annual snowfall
amounts to less than half an inch of equivalent Uquid
water. The valleys are kept both cold and dry by cold,
dense air masses that form on the polar plateau and
then tumble down the valleys in what are called kataperature
is
batic winds, displacing
warmer
air
over
ture. Finally,
NATURAL HISTORY
and
how it may
respond in the futhe glaciers impinging on the Dry Val-
ations in the past,
July/August 2005
McMurdo
Sound. As the air descends from the plateau,
it
amplifying its
Summer,
ability'
to evaporate moisture.
near freezing. In Wright Valley, the
how
is
floor of the valleys the average annual
naturally,
into igneous geology, as well as into
at all
Mountains dam the East
Sheet, largely preventing it from flow-
that the Transantarctic
of Hquid water locked within subliming lake ice for
hundreds to thousands of years. The region opens a
the Antarctic ice sheet responded to cUmate fluctu-
I
The
ty miles away.
not melt; inicrobial communities that Uve in bubbles
window
28
West Antarctic Ice Sheet, which
rests on an ancient bedrock that
would be submerged, were it not
topped by ice.
Immediately to the east of the
Transantarctic Mountains, the
Dry Valleys extend from the polar plateau seaward toward McMurdo Sound, an arm of the Ross Sea, roughly six-
is
the
"warm"
water collects in the
in Antarctica
what
is
—
hardly
a
warms,
season, with temperatures
Onyx River,
summer
melt-
the largest "river"
rather highflown description for
more than
a trickle in
the Antarctic
summer and nonexistent the rest of the year.
The lakes scattered throughout the valleys
are
which is typically ten feet
They would probably freeze completely were it not for the summer sun that warms
them and the ice cover that insulates them during
the winter. In fact, the bottom of Lake Vanda, in the
bowl-Uke pools
Because the summer air
temperature is commonly stiU below freezing, the
"holes" remain sealed by ice. Nevertheless, the water collects in small, coalescing passageways and
eventually trickles out of each glacier.
perennially covered by ice,
more
or
ice, leaving,
heart of Wright Valley, is 226 feet deep; there, the
water temperature is a comfortable seventy-nine de-
Despite being fed by meltwater, most of the lakes
The
hold.
For example, the sahnity of Lake
Vida, in Victoria Valley,
water.
basic reason for the high saUnity
the lakes are extremely old
—old enough
is
The
also
that
for salt to
occur in the lakes of the
form
algal mats.
come
encased in ice that migrates upward
Sometimes pieces of the mats be-
of the ice subHmes. The process takes
the lakes bring only minuscule amounts. Funda-
and microbial mats
ice cover
The
subHmes and
lost ice
is
bottom of the
is
the top of each lake's
as
lost to the
replaced by
new
"cold-based,"
which means
unhke nearly
all
frozen.
as
old
as
as
the top
long time,
2,800 years have been
is limited to a few
lonesome Hchens, which grow on protected rock surfaces, and to several species of microscopic worms
known as nematodes, which live in the soil in the few
places that become damp in summer.
Since nearly all of Antarctica is covered by ice,
at the
ice cover. In the process, salt gets left
behind in the Uquid water.
The glaciers of the Dry Valleys are
lakes. The glaciers are said to be
Antarctica,
forming
as
a
identified. Besides bacteria, Hfe
dry atmosphere.
ice
ice,
The same organisms
Dry Valleys, where they
have built up, even though the waters that enter
mentally, the lakes lose water
finds a toe-
life
cryoconite holes, encased in
host communities of bacteria.
seven times that of sea-
is
glaciers,
Where liquid water does occur,
grees F (twenty-six degrees C).
are extremely salty.
within the
called cryoconite holes.
thick.
exotic as the
that,
glaciers outside
bottoms
their
are
That property makes them
such
Greenland or the high peaks of
act idiosyncratically. In places
as
the Alps, "wet-based" glaciers
scrape the bedrock over which they
up
flow, picking
tities
of rocky
substantial
debris.
quan-
Where
the
ice melts, the debris accumulates in
ridgeUke piles
known
as
moraines.
Cold-based glaciers, by contrast,
flow mainly by deformation; the
ice itself flows hke putty, pushed by
its own inexorable weight. These
glaciers pick
up very
Httle debris,
cause Utde erosion, and leave only
small moraines. Cold-based gla-
even look different. Instead
of being thick rivers of ice fuU of
ciers
crevasses, the glaciers
Dry
Valleys are
flat
within the
and rather
smooth; some are even shaped Uke
pancakes. They, too, lose their ice
mostly by subHmation, so
no meltwater
issues
The enormous
ciers,
such
as
ter.
riverlike gla-
of the major
do provide some Uquid wa-
summer
Wall
a side canyon of
in
base
is
magma
rock
—
a talus slope
upper Wright
made
Valley
exposes two dark bands of rock: at the
of those rocks. Each
band
is
a basaltic
sill,
formed when
intruded into and then solidified between the layers of the surrounding
in this
instance, light-colored
they absorb solar
ping the
cliff
which melts the subsurface
800 feet
thick.
In
heat,
or
the Taylor Glacier,
that enter the heads
valleys
Uttle
from them.
Beacon sandstone. The topmost dark body capis the Asgard Sill, here about
Mount Fleming Sill; below that
To the right is Wright Upper Glacier.
face
is
the
July/August 2005
NATURAL HISTORY 29
carved sinuous valleys with
floors
flat
and steep semi-
circular walls.
The
form much
later
than the valleys did, about 34 million years ago.
The
Antarctic ice cap began to
fundamental cause was the opening of the Drake Passage, the part of the Earth's great Southern Ocean that
separates Antarctica
from South America. The new-
circumpolar ocean established a circumpolar current that blocks the southerly flow of warm water and
ly
thermally isolates Antarctica from the rest ofthe world.
which
In contrast to the Arctic,
is
highly sensitive to
global climate change, the Antarctic cHmate has re-
mained
relatively stable for millions
Early on, glaciers did cover
The
leys.
of years.
much of the Dry
glacier traces are hard to miss:
Val-
rock surfaces
have been scoured smooth, and rocky, gravelly debris
known as glacial till has been scattered throughout the
high
valleys.
But by about 14 million
—except
today—had
glaciers
years ago, the
of
from the valleys. How
some of the surfaces high
for the small, cold-based glaciers
largely disappeared
do
geologists
know?
above the valley
some
Geologic strata exposed at one or another part of the Dry
Valley walls
as
shown
in
and
floors include four basaltic
sills
(dark blue),
in crystals
sills
of the mineral or-
vening rock layers. The topmost stratum
still
is
made up
—
wind to have blown away. Those regions of
Dry Valleys have remained hyperdry, hypercold,
and
glacier-free, at least since the ash
don't
molten, after ascending
by the
one might reasonably suppose that the Dry Valleys
were simply carved by glaciers that overtopped
the Transantarctic Mountains. Unlike rivers,
which tend to cut valleys that are V-shaped in
cross-section, glaciers characteristically carve a U
(think of California's Yosemite Valley) The walls
and floor of the lower reaches of the Dry Valleys
.
indeed shaped
like a U,
but to the practiced
eye the U looks too wide and too shallow to have
solely glacial.
The most
evidence of how the valleys did
telling
form occurs at high
elevations,
discovered reinnants of
steep-waJled valleys.
relics
flat
The
of river erosion 55
where
geologists have
surfaces interrupted
latter valleys
iTullion years ago,
when
no
ice.
those days, in a sense, Antarctica did not exist
was stOl attached to Australia
tinent
known
as
Earth today that
as part
Gondwana. There
may bear a
by
appear to be
climate was semiarid and Antarctica had
It
at
the
In
all.
of a larger conare places
on
close resemblance to the
One of them is the
Colorado Plateau of southern Utah and northern
Arizona, where seasonal rivers and streams have
Antarctic landform back then.
30
NATURAL HISTORY
July/August 2005
just beneath the
the
mean
fell.
sea:
happened
were flooded
to suggest that nothing has
of the
valleys
nine-rmllion-year-old sediments, typical
of the sediments
been
lie
the loose rock and gravel too heavy
I "recently." Low parts
of
through the labyrinth beneath.
are
deUcate volcanic ash deposits,
13.6 million years,
from basaltic dikes, or
vertical intrusions of once-liquid rock, that cross the inter-
basaltic lava that erupted,
as
for the
Bruce Marsh of Johns Hopkins University. Tongue-shaped
thopyroxene protrude into the
old
desert pavement
the schematic diagram, based on a model by
regions of basalt (gray) rich
as
On
floors,
at
the bottoms of fjords, remain in
the floor of Wright Valley. Similar deposits, aged be-
tween 6 million and 3.4 million
years,
lor Valley. Since then, the region has
occur in Tay-
been
uplifted
and so the major valley floors are now mostly a few
hundred feet above sea level. There was also a period of glacial advance, about 3 million years ago, when
the Taylor and Wright glaciers expanded into the
lower parts of their valleys and left deposits of tiU as
their calling cards. At various times, sea ice has also
invaded the lower valleys. In brief periods of relative
warmth, glacial meltwater accumulated behind this
ice to form small, temporary lakes. Their sites are
marked today by local beds of sediment in the valley
floors. Yet none of these events fundamentally altered
the landscape; the vista we gaze on today has remained
largely unchanged for at least 14 million years.
In today's valleys, the Ferrar dolerites occupy four
massive siUs, each between 330 and 1,150 feet thick,
interconnected by a series of dikes [see illustration on
this page]. The intricacy of the array is accompanied
by a wide variation in the composition of the
rocks
a variation presumably related to the way
the magma solidified. Unlike water, which freezes
—
«*»<S5^
at a single
temperature, magnia freezes
over a temperature interval. Most
magmas are completely
molten at 2,200 degrees F (1,200 degrees C) and do not become completely solid untU the temperature tails
to about 1,650 degrees F (900 degrees
C) As the magma cools between those
two temperatures, different minerals
basaltic
.
or freeze out,
crystallize,
at different
temperatures. These minerals are not
magform
the same in composition as the
ma
itself.
Therefore,
as crystals
and sink or otherwise separate from the
the composition of the resid-
magma,
magma
ual
changes.
In a cooling basaltic
mineral to crystallize
magma,
the
first
usually oUvine,
is
magnesium silicate (MgiSiOJ that also includes some dissolved iron. In the
a
case of the Ferrar dolerites, the
fireeze
first
to
out was orthopyroxene (MgSiO,
with about 15 percent dissolved
Because orthopyroxene
—
iron).
and, for that
—both have
a
higher
proportion of magnesium than
magma
matter, olivine
does, the
falls as
magnesium content of the
these minerals crystaUize.
Tongue of orthopyroxene-rich basalt, emin the Basement Sill, is exposed in
Wright Valley; its position is shown in
schematic diagram at right. The tongue has
been eroded by wind and is now covered
with sand that makes it look smooth. The
reddish striations above and below the
Basement Sill are basaltic dikes that predate
bedded
the
When
sill.
residual
magma
As cooling contin-
mixture of two kinds of aluminum
and the pyroxene mineral augite (a magnesium silicate mixed with some iron) form.
ues, plagioclase (a
silicates)
The
our most
distribution
rar dolerites.
up of dense,
ible
of orthopyroxene proved to be
understanding the Fer-
telling clue for
Looking
see clear differences
black,
closely at the rocks,
we
could
Some
are
made
among
the
siUs.
homogeneous
basalt,
with no
vis-
mineral grains. Others have varying abundances
of orthopyroxene crystals suspended in otherwise
fme-grained rock. In consequence, the rock varies
from 3 percent to 12 percent magnesium, depending
on the proportion of orthopyroxene.
Marsh and his students have meticulously mapped
those proportions. The maps show that orthopyroxentirely
ene
crystals are distributed
within the
siHs in
great
tongues, sometimes extending for tens of miles along
the
sills.
The orthopyroxene-rich tongues
—occupying
est
are thick-
perhaps half the height of a
sill
where the siUs appear to have fiUed from their feeder
dikes, and they thin from the filling points toward
the more distant parts of the siUs.
Given the high melting point of orthopyroxene,
its
distribution into tongues suggests
it
froze out
of
the melt deep in
magma
the
of the mineral were then carried in
sills.
Crystals
the
sill
intruded,
it
cut
through those dikes.
chambers, before
it
reached
suspension by the upward-moving
magma and
forced toward the center of the flowing slurry.
When
ers
the flow of magma intruded
of rock
sill
as a siU,
margins.
The
between
lay-
the Hquid began to solidify at the
"soUdification front" then pro-
ceeded inward as the basalt continued cooling.
Meanwhile, the suspended orthopyroxene crystals,
most of which were now near the center of the siU,
slowly settled into the lower part of the magma in
which they were suspended. When the solidification front
moved
entirely
through the
siU,
pre-
it
served the tongue-shaped distributions of orthopy-
roxene
crystals
we
see today in the valley walls.
Elsewhere in the world, geologists have studied
vast bodies of well-layered igneous rocks. Some of
those rocks hold important deposits of metals such
as platinum, for reasons that may be related to the
rock-layering process. The layering has thus en-
gaged the attentions of several generations of earth
who continue to wonder not only about
ore deposits, but also about the larger lessons the
layered rocks may hold. In the Dry Valleys of
scientists,
Antarctica,
where the Ferrar
dolerites solidified
have caught the layering process
Thanks to the fortuitous circumstances
rapidly, geologists
in the act.
that
are
keep the landscape
among
free
of ice, the Dry Valleys
the planet's best places to study
various kinds of rocks form, and even
deep Earth organizes
how
how
the
D
itself.
July/August 2005
NATURAL HISTORY
31
rn
In the Heat
of the Night
An
assassin bug's sensory journey
By Graciela Floras
of Latin America, adobe houses with thatched roots are
of the landscape. The houses are crisscrossed by crevices that
rural areas
In
fixtures
down,
and antennae start to disentangle. One
by one, the insects come out and start their nighdy search for blood. They
are called kissing bugs or assassin bugs in English, but in Latin America they
serve as hideouts for insects. In the evenings, as the sun goes
masses of intertwined heads,
have
legs,
many regional names. In my home country' ot Argenrina, we call them
word derived from Quechua (a family of languages dating back
vinchucas, a
which means "those who let themselves fall."
These insects are bloodsuckers, and when searching tor a blood meal
they honor their Quechuan name: because they are such bad fliers, they
let themselves drop from walls and ceilings. Once on the floor, or ^^•hile
crawhng down the walls, the insects skiUfuUy navigate the intricate microlandscape of odors, shadows, and temperatures they encounter. When a
vinchuca fmds a host a dog, say, or a sleeping human it s\\'iftly locates
a blood vessel. Next, it extends its proboscis, a beak neatly folded under
its head, and pierces the skin of its victim. As it feeds, the bug injects a
cocktail of analgesics, anticoagulants, and vasodilators that help the blood
flow smoothly and painlessly.
Slowly, the vinchuca grows, as Charles Darvwn described with disgust
after being attacked by one in Argentina, from "flat as a wafer to a globular form," as it becomes "bloated with blood." While still feeding, the insect releases urine and feces on the skin of the host, making room in its
abdomen for the enormous amount of incoining blood. [See photographs
to the Incan Empire),
—
v^\*-:.
oi;
—
page 34.]
The vinchucas
—
avzi
e.xcretions can
harbor
a
protozoan
The
the cause of Chagas' disease.
sucked up when
from another animal, and get
infected host. Thus the \anchuca
When
eventually
other
bodv
droppings can
move through
tissues.
as Tr)'patiosoma
come,
the insect feeds
acts as a carrier,
a healthy bite \'ictim scratches at a
parasites in the
known
T. cnizi parasites
or vector, for
vinchuca wound, any
slide inside the vdcrim's
open
in turn,
on
that
77 cnizi.
T cnizi
skin,
and
the bloodstream to colonize heart muscle and
mmm rM^^m^igti^gimmmi^imm^
^ssssa..
Symptoms of Chagas'
Some
disease vary dramatically, particularly in the ear-
effects, whereas others experifew weeks after being bitten. About a
quarter of the infected population suffer from serious heart or digestive
disorders, which only develop decades after the initial infection. Of the
some 20 million people in Latin America now infected with T. cntzi, about
50,000 die every year. Those figures make Chagas' disease one of the most
widespread and economically devastating tropical diseases in the world.
And tor poor countries, in which substandard housing is widespread, the
total economic loss due to Chagas' disease is staggering.
ly stages.
ence
people never develop side
fever, rashes,
and fatigue
a
A
are relatively unknown in big cities, simply because urban
housing does not offer them appropriate refuges. As a cit>' dweller
myselt, I did not encounter a vinchuca until I became a graduate student
in the Laboratory ot Insect Physiologs', at the Universit}' of Buenos Aires.
There I was part ot a team trying to answer some of the many outstanding questions about vinchucas. As my colleagues and I immersed ourselves in the study of the insect and pooled our results, we were able to
Vinchucas
reconstruct the insect's sensory trip from
common
In
usage, the
concentrated on one,
its
refuge to
term "\dnchuca" can
Triatoiiia iiifestaiis,
Argentina and Uves almost exclusively in
which
its
refer to
host.
many
species.
We
thrives in the arid north
human
dwellings.
When we
of
start-
ed our research, the behavior of T iiifestaiis was not well understood. The
director of our laboratory, Claudio R. Lazzari, had surveyed the species' behaviors during his
own graduate work,
with the insect physiologist Josue A.
Nunez, also of the University of Buenos
a few other insect physi-
Aires.
From
Lazzari, Niiiiez,
and
.H-
m
we knew that
T. iiifestaiis could home
ologists,
in on an animal's
vessel
even in
blood
a pitch-
we
know how it
dark room. But
did not
accomplished the task.
Odors, chemicals, and
heat
all
clearly played a
Vinchucas spend their days
crowded together in refuges such as
the crad<s of adobe houses in rural areas.
The interior of one such house is shown im
pressionistically on these two pages. At
dusk, the internal clocks of the vinchucas
set the insects on their nightly search for a
blood meal.
-*i
about exactly how the
So we divvied
up the various aspects of the vinchucas' biology and
behavior among the members of our team. I focused on the thermal sense
to me, the most fascinating sense of all.
By day, the vinchuca remains in a sleeplike state
but
role,
we were
clueless
insects exploited that information.
—
known
At dusk, however, the insect is
by an internal biological clock, which regmost of its behaviors. The newly awakened
as akinesis.
their high temperatures help disperse chemicals
by
creating local convection currents.
One
blood
of the best indicators that a good source of
nearby is a gas that, to us, is odorless: car-
is
bon
dioxide. Most blood-sucking insects, including
mosquitoes and vinchucas, however, can smeU carbon dioxide, and they rely on that cue in their search
My
for a host.
colleagues discovered that an inter-
activated
nal clock controls the sensitivity of vinchucas to car-
ulates
bon
dioxide.
turns out that the insect's sensitivity
It
is
highest in the
first
hours of the
night, at the start of their journey.
Vinchucas have olfactory receptors
for dozens of other scent molecules
as well as for carbon dioxide.
Upon detecting a promising odor,
the vinchuca adopts a new tactic: it
^S\
travels
"upwind," against any local
currents of
air,
to get closer to the
As it follows the current, the
insect gauges its direction with
source.
Vinchuca (Rhodnius prolixus), the species
for
first
studied
out "thin as a wafer, " as Charles Darwin noted,
in
in
the 1920s
response to heat, feeds on a human host. The insect starts
its
and empties
size
bowels as
its
it fills
left,
with blood, right.
dant on the antennae. In a
—
—
on its four rear legs,
the in-
For
ready to go.
bite.
As the
last
hints
of daylight disappear, the insect
randomly walking, moving its antennae
smoothly up, down, forward and backward. Every
and the smooth,
sweeping antenna movements become jerky, resembHng the old semaphore method of flag signaling. The vinchuca is sampUng the air.
The vinchucas antennae are remarkable structures. Less than a third of an inch long in adults and
even shorter in the larvae, the antenna is the seat of
thousands of so-called sensiUa, the insect's sense orso often, though, the insect pauses,
is
[see illustration
a sensory unit
on opposite page] Each sensillum
.
made up of one
or
more neurons,
plus supporting cells that nourish them.
silla
endow the insect with senses of heat,
The
sen-
smell,
and
touch. Taken together, the antennae and their sensiUa are the insect
s
window on
the external world.
all
heat
in
The
wandering vinchuca, antennae waving, has
entered an odor plume. Mists of molecules
bump into the insect. Some of the molecules penetrate the insect's cuticle through minute pores and
reach the olfactory sensiUa just beneath.
blooded animals
NATURAL HISTORY
are
July/August 2005
Warm-
an endless source of odors, and
smeU and touch,
the vinchuca's sensitivity to
is
the ultimate stimulus that prompts
it
to
We devised a way to demonstrate that behavior
the laboratory. We heated a piece of metal to the
warm-blooded animal
surface temperature of a
about ninety degrees Fahrenheit (thirty-two degrees
Celsius)
—and brought
the metal within range of a
vinchuca's proboscis. Immediately the vinchuca ex-
tended
its
proboscis and repeatedly tried to bite the
metal. Furthermore,
when we
cooled the metal to
below ninety degrees Fahrenheit, no other stimulus
we presented could induce the vinchuca to extend its
proboscis.
we
days,
My
Even
if the insect hadn't
could not get
it
eaten for forty
to bite a cool surface.
colleagues were able to
one way
come up with only
to circumvent the vinchuca's virtually au-
They placed
tomatic response.
warmed
a
miniature copper
of a warm-blooded animal, near the vinchucas' antennae, and tricked
rod,
to the temperature
the insects into drinking cold blood.
imagine
34
new state
lifts
starts
gans
as
of alert, the vinchuca closes in on its intended host,
and as it does, it enters an undulating landscape
of temperatures.
both front legs and unhurriedly draws first
one antenna, then the other, through small combs
on the inner sides of the two front legs. Now it is
sect
known
mechanoreceptors, which are abun-
vinchuca raises its antennae its sensing instruments and, usually, grooms them: a mesmerizing
process. Standing steady
motion-sensitive hairs,
but balloons
a clearer,
It is
hard to
simpler demonstration ot
important thermal sensiUa are to the
how
insects' feed-
ing routine. Odors from a potential host initiaUy
attract vinchucas,
but heat
is
the only stimulus both
necessary and sufficient to get
A
sect's
current of warm
air
has
them
now
to bite.
reached the in-
sweeping antennae. As the thermal sensiUa
warm
up. Vinchucas, like
Vinchucas are also unusual in that their antenna car-
most animals, can detect heat through conduction
ry a kind of sensiUum observed in only a few other
or through rising
blood-sucking
absorb the heat, they
air currents.
Amazingly, though,
—known
the insects can also sense radiant heat
insects: the
"cave organ." Since
its
dis-
as
covery in the 1950s, the function of the organ has
Lazzari and Nuiiez discovered that capability
been a mysteiy. It is a pit (hence its name) lined with
hundreds of thin, short hairs that have no pores. Each
infrared radiation.
when
they placed windows, impenetrable to in-
between the
frared radiation,
heat
—^which
insects
and
a source
was, again, a miniature metal rod
antenna, moreover, has only one cave organ, in sharp
of
contrast with other kinds of sensilla that
at
the hundreds, Lazzari
showed
number
that the cave
in
organ re-
the right temperature. All the vinchucas' usual re-
sponds to heat but not to odors, and suggested that
it
sponses to heat disappeared, but were duly restored
might be acting
is
when
still
the experimenters replaced the infrared-
opaque window with
The
frared rays.
changes
C)
as
a
insects
window
known. Only
known to be
de (Melanophila
—an
fifty
craftsman-
tools he or she needed. That rule was mainly driven
by the bug-size devices that had to be custom-made
for each experiment. But it also stemmed from a tradition in entomology, inherited from such early in-
insect able to detect
miles away.
EngUsh entomologist Vincent B.
Wigglesworth. Wigglesworth began his studies on
anothervinchuca vector of Chagas' disease, Rhodiiius
vestigators as the
respond to heat; chemoreceptors (c)
bind to scent molecules; and the solitary cave organ (d) one
per antenna may help the insect detect infrared radiation.
—
—and good
few other animal
a
Thousands of sensilla cover the vinchuca's antennae:
mechanoreceptors (a) give the insect a sense of "touch;"
thermoreceptors
minuscule
ship as well. In our laboratory, everyone created the
sensitive to radiant heat, in-
aaimiiiata)
from nearly
the vinchuca's response to heat requires
a love for the
the most thermally
cluding boas, pit vipers, pythons, and the jewel bee-
forest fires
Studying
small as 0.0072 degree F (0.004 degree
sensitive animals
species are
clear-cut evidence supporting the hypothesis.
transparent to in-
could detect temperature
—which makes them among
no
an infrared receptor. But there
as
(b)
—
and became the first to study
encountered a problem
that many others have faced as well: As an insect walks,
prolixus, in the 1920s,
its
response to heat.
He soon
July/August 2005
NATURAL HISTORY 35
is shown schematically. The
was tethered to a stand and allowed to walk in place, while it held on to a rounded, tetrahedral Styrofoam object called a spangenglobus. Warm metal plates of equal size and temperature were placed at various distances (A, B, C), and smaller plates, subtending the same angles
as the plates at distances B and C, were placed at distance A (pink and yellow rectangles). The
insect spread or closed its antennae as the plates varied in distance or size, just as if it were
"measuring" the angle of each plate from its point of view. Thus, with an independent estimate
Experimental apparatus for testing a v/nchuca's responses to heat
insect
of distance, the vinchuca could also estimate the true size of
its
amount of heat reaching it constantly changes.
How, then, can the experimenter maintain a con-
that
between the insect and the heat source,
and thereby control for the heat reaching the insect,
without stopping the insect from walking?
The problem was ingeniously solved more than half
from Lazzari: ten
I guarded the
little treasures with zeal and kept them together with
ten custom-made acrylic boxes, ten diminutive copper pincers, a miniature brush made of my own hair,
and a few sohd aluminum plates that served as heat
the
stant distance
a
The German
century ago.
behavioral biologists
Bernhard Hassenstein and Werner Reichardt devised
the celebrated
^in the world of entomologists
span-
—
genglobus.
hedron
The
device
been
that has
is
essentially a
miniature tetra-
"inflated" into a
more
nearly
spherical shape about three quarters of an inch in di-
ameter.
The
tetrahedral
material such as balsa
The back of the
framework
is
made of a
light
on
the
left,
insect, in
1
mrn,
is
glued to
a
rod that
cause the spangenglobus weighs about the same
hoUow Styrofoam
With
sources.
more
quired
its
own weight. To the insect,
then, holding
surface of the spangenglobus as
guishable from walking upside
as
the
it
walks
down on
is
a
on to
the
indistin-
soUd sur-
Like Lewis Carroll's Red Queen, the insect walks
and walks, only to stay in the same place.
The tetrahedral shape also has a clever purpose. Be-
face.
come together at each vertex, when-
ever the insect walks up to a vertex,
it
faces a choice
to proceed, left or right. If the experia stimulus
July/August 2005
tool kit
We
sophisticated gadgets, but the
itive tools,
were by
I
stud-
later acfirst
ex-
far the
most
interesting.
spangenglobus,
had
With
behavior of blinded vinchucas —
had been covered over with
—when he con-
on
the right different fi^om
Lazzari
the
tested the
their eyes
paint
them with
temperatures.
legs
NATURAL HrsTORY
homemade
periments, the ones conducted with the most prim-
and walk, just as ifit were walking upside down
and gripping a ceiling with enough force to support
its
menter presents
this basic
balls.
ied the vinchucas' responses to heat.
fronted
of two ways
insect turns,
my spangenglobuses
inherited
hand-carved
insect does, the insect can grab the spangenglobus with
cause three edges
and notes which way the
the animal s behaviors can be studied in detail.
wood or, in our case, Styrofoam.
suspends the insect directly beneath a frxed frame. Be-
36
potential host.
pairs
of metal
He found that
plates at different
the insects walked to-
ward temperatures close to that of a warm-blooded animal, away from plates that were hotter, and
were unaffected by the ones at room temperature.
This result might seem obvious, but it is not. It has
an important imphcation: the insects can estimate
the temperature of a distant object. Furthermore, in
experiments the vinchucas never raised
an attempt to bite the warm
metal plate: they "knew" it wasn't close enough,
even though their eyes \vere covered.
In another experiment, this time with unre-
Lazzari's
their proboscises in
strained, freely
I
walking
—
^but
still
blind
—
the insect's point of view
vinchucas,
—
of the actual
regardless
observed that once the insects reached the heat
size
or distance of the source. In other words,
and pierce the
two
plates
source, they repeatedly tried to bite
all extended their proboscises when they
were about half an inch from the source, even though
they could not see it. Did that imply that they could
estimate distance as well
as
To answer
it
sensilla.
When
which
itself
is
fires
confi^onted with
amount of
not enough to discriminate sources
—
at differ-
or small
—hot
warrmng as a
or larger
cool source. Thermal sensilla
closer
alone cannot distinguish those two conditions, but
source could produce the same local
—
—
istics
brain.
might be recognizing two characterof the heat source: distance and size, and "cominsects
puting" a third characteristic,
size,
—
size. If they
first
inversely propor-
is
tional to the square
of the
within half its
initial
distance
from the heat source, the
sect gets four rimes as
and geometric circumstances, maybe they could
heat
"calculate" the third.
quarter of its
initial distance,
teen times its
initial level.
antenna movements of
as it
got
dis-
tance. If the vinchuca walks to
then, given the basic physical
The
given source increas-
the heat
antennae
the size of a host.
these variables,
a
vinchuca gets closer to that source, but the
increase is not proportional to the distance. Instead
helps vinchucas estimate
could estimate the
two of
insect thus estimates the apparent area, or
The amount of heat from
Vinchucas could gauge distance we had
ample evidence of that. But I
w^as determined to find out
Spreading their
about their ability to discern
perature.
The
of the heat source.
es as the
actual surface tein-
its
into
port the antenna position to processing centers in the
vinchucas certainly can.
The
fall
of size might be accounted for.
Let's go back to the vinchuca once more and reconstruct the last part of its journey. The insect, attracted to a host by its smell, enters the thennal domain. Close enough to perceive the host's heat
through thermal receptors, it turns and faces the
source of heat. Scanning the air, it follows the edges
of the heat source with its antennae, whose position
is being closely monitored by mechanoreceptor hairs.
These hairs bend when the antennae move, and re-
neurons. But that information, by
ent temperatures, because a distant
the antennae
made the same angle with each other. The pieces
of the thermal puzzle were beginning to
was time to ask how.
what hap-
a heat source, the sensilla receive a given
when
big and
place: the variable
that question, think about
pens to the thermal
heat,
also
temperature? Abundant
evidence suggested they could;
other small and nearby
far away, the
metal; they
—one
—
subtended the same angle
at first; if it takes a
few more
in-
much
steps, to a
the heat increases to six-
We think such rapid changes
walking vinchuca, which I knew in great detail, gave me an
idea. Confronted with a warm source
or with the
hand of the experimenter, for that matter
vinchuca walks toward the potential blood meal,
opening and closing its antenna. Perhaps those antenna movements, which expose the thermal re-
in heat play a key role for the insect in determining
ceptors to the heat source, were also enabling the
ue to the second
a
—
vinchuca to estimate the
I
devised two
tests
size
the insect; in the second,
various distances
I
In the
first, I
size at a frxed distance
from
put a single heat source
[see illustration
at
on opposite page]. In
both experiments, I filmed the vinchucas on the spangenglobus as they reacted to heat, and digitized the
positions of the antennae every second.
filmed positions
I
From
the
determined the angles between the
test to test. To my
antenna aperture
changed with both the size of the source and the distance between the source and the insect.
antennae and compared them from
amazement,
I
found
position with respect to the heat source. For ex-
ample, a vinchuca might measure the
received in two different parts of
head and the rear end.
heat received
that the
at
amount of heat
its
body,
say,
the
By comparing the amount of
those two points,
it
could estimate
the distance to the heat source and thus assign a val-
Knowing
of the source.
my hypothesis.
for
put heat sources of various
—
its
variable.
the area and the distance, the vinchuca
could "derive" the
third,
and
crucial, variable: the
actual temperature of the heat source. If it
known
fell
in the
range of temperatures of a warm-blooded
animal, the vinchuca might as well try for a meal.
Thus ends
trip
a bug's trip
from
its
refuge to
a host, a
aided by amazing sensory instruments.
It is
a
journey repeated endlessly by millions of vinchucas
every evening, across Latin America. In spite of the
vinchuca's superior homing skills, this journey
would not be possible without a proper refuge during the day.
And yet, in many countries, the straight-
that the position
forward approach of improving housing conditions
fdhng in nooks and crannies remains only
a dream, and the insects continue to have free reign
tently,
on their nightly forays.
When I plotted the angular values, it became clear
of the antennae simply, and consisfollowed the apparent size of the source from
—
—
D
July/August 2005
NATURAL HISTORY 37
Unhappy Trails
new
Forensic examination of ancient remains sheds
on the emergence of Florida's Seminole Indians.
By Christopher M. Stojanowski
Onjanuary 30, 1838, the Seminole war hero
Osceola died of malaria while in captivity
at
Fort Moultrie, South Carolina.
The sev-
eral hundred Florida Indians under his leadership had
been waging guerriUa-style warfare against United
States forces for a few years. Three months earlier,
with expenses and military casualties mounting, the
U.S. Army General Thomas S. Jesup, under the pretense of offering peace negotiations,
had lured Osceola to Saint Augustine,
Florida.
When
Osceola approached,
Jesup s soldiers had captured and im-
prisoned him.
The intention had been
to break the spirit
of his group of rene-
gades and expedite the removal of all
the Seminole to lands west of the Mis-
designated
sissippi,
in captivity,
shown
as
in this lithograph from
838 portrait by George
Catlin. Osceola and his followers had been resisting relocation out of Florida under the
terms of the 1830 Indian
Removal Act.
an
1
period of uneasy peace, warfare had
The causes of the Second
Seminole War were numerous, but central was the
refusal of the Seminole to relocate, as prescribed by
830 Indian Removal Act. By the end of the war,
thousand Seminole had complied
with the removal. But some hundreds remained in
Florida. Their leader, BiUy Bowlegs, was finally defeated in the Third Seminole War (1855-1858), and
he consented to lead his people to Indian Territory.
The ethnic cleansing of Florida was all but complete;
as few as 200 Seminole Ungered on, deep in the Everglades, far removed from American contact.
But who were the Indians known as the Seminole,
who clung so tenaciously to their homeland? At the
time ofEuropean contact, in the early 1500s, the tribes
in what is now Florida and southeastern Georgia inthe
1
in 1842, several
cluded,
inhabiting the southeastern U.S. had
Ocale, Potano, Tequesta, Urina, and Yustaga. Those
ney.
Seminole leader Osceola posed
Indian Territory.
a
The members ofthe other maj or tribes
already
proudly even
as
Following
erupted again in 1835.
been forced
They were
to
make
the jour-
the Chickasaw,
—
Choctaw, Creek, and ^remembered
for the infamous "Trail of Tears"
the
Cherokee. But the Seminole were not
about to give up. What was known as
the Second Seminole War would last
—
another four years.
The First Seminole War, from
1817 until 1818, had also been
fought between U.S. forces and
Seminole bands, even though at the time Florida
belonged to Spain. Among the U.S. justificawas the unwillingness of the
Seminole to return fugitive slaves to settlers' plan-
still
among
others, the Apalachee, Calusa, Guale,
populations had roots going back thousands of years.
But no
itself
tribe
1760, and
ish
named "Seminole" existed. The term
come into general use until about
did not even
word
The
it is
thought to be a derivative of the Span-
dmarron,
meaning "wHd" or "untamed."
standard account of Seminole origins
is
that
two centuries of disease, European conflict, and
harsh colonial policies, Florida and southeastern
Georgia were essentially devoid ofindigenous groups.
The region was then repopulated during the mid1700s by Creeks fi-om central Georgia and Alabama.
Those Creeks that settled in Florida then became culturally distinct and began to be called Seminole. Acafter
tions for the incursion
tations. By the time the war ended, many Indian
towns in Florida had been burned by General An-
drew Jackson, the fliture president, whose scorchedearth campaign against the Indians also led Spain to
abandon their troubled colony.
38
NATURAL HISTORY
July/August 2005
Seminole Tommie Jumper wears garb typical for tribesmen
living in Florida in
the late nineteenth and early twentieth
and flowing shirt. Jumper
was a descendant of Indians who eluded relocation to what is
now Oklahoma. The author has investigated the biological
centuries, including turban, scarves,
origins of the Seminole, a tribe that did not exist in
the time of European contact.
name
at
July/August 2005
NATURAL HISTORY 39
more durable
cordingly, Florida's native populations are typically
dition to
divided into two groups, pre-Seminoie and Semi-
and stone
nole, in recognition
That,
at
any
of their disjunctive histories.
what the evidence from liis-
rate, is
documents and archaeology shows. But another line of evidence can be brought to bear on the
question of Seminole origins: bioarchaeology, the
study of human remains excavated from cemeteries
and other archaeological sites. Ample physical reexist for the crucial
from the
transition
tribes to the
I
time period covering the
of the original indigenous
advent of the Seminole. In
my research
have sought to reconstruct genetic relationships and
how
I
last
they changed
have sought to
among the principal
relate
known on independent
my
groups, and
observations to events
historical or archaeological
artifacts
such
human
textiles,
as
bone,
antler,
brain tissue, and
botanical remains from stomach contents, representing medicinal concoctions and "last meals."
Archaeologists distinguish several cultural areas that,
torical
mains
—
tools
by about 2,000
years ago,
were the precursors of the
first European explorers
groups encountered by the
and Georgia. Most groups practiced some
form of horticulture, tending early New World domesticates such as squash, sunflower, and maize.
in Florida
Where
and shellfish, as well as terrestriwere an important part of the diet.
The first European credited with setting foot in
the Florida peninsula is Juan Ponce de Leon, who
explored the coast in 1513. He claimed the peninand much of the surrounding territory as
sula
well
for Spain, naming it La Florida, because he
al
available, fish
animals,
—
—
discovered
it
in the Easter season (also
known
as
Other exfollowed, including Panfilo de Narvaez and
pasmajlorida, or the feast of the flowers).
plorers
Hernando de
when
Soto, but
it
wasn't until the 1560s,
the French began to position forts along the
southeastern coast of North America, that Spain es-
tabHshed a permanent colony. In 1565 the Spanish
Menendez de Aviles expelled the
French and founded the city of Saint Augustine.
As part of his royal charter, Menendez was charged
with converting La Florida's indigenous populations
to CathoHcism. This task was taken over in 1573 by
the Franciscans. During the next 125 years, the friars expanded their reach, converting numerous populations living along the coast of what are now Georgia and northern Florida, throughout north-central
Florida and adjacent southern Georgia, and in the
Florida panhandle. At the height of missionary expansion, during the 1600s, dozens of missions served
tens of thousands of converts.
naval officer Pedro
Map
depicting the Spanisli claim over what
made
is
now the
south-
1742 by the Spanish army
royal engineer Antonio de Arredondo. The image, a detail of
a 1914 copy of the map, shows that some areas were in diseastern United States was
in
pute, but that Spain recognized other areas as legitimately
occupied by England and France under a 1670
treaty.
The
Spaniards placed their missions in three
regions serving three major groups of Native
The results bring into doubt the "common
grounds.
knowledge"
that native Floridians
fall
neatly into
pre-Seminole and Seminole groups.
main
Amer-
Timucua, the Guale (pronounced imlfy),
and the Apalachee [see map on opposite page]. The Timucua lived along the northern Atlantic coast of the
icans: the
Florida peninsula, throughout the north-central in-
The
between 12,000 and 10,000
first
people to reach what
is
now
Florida,
were nomadic hunters and gatherers whose ancestors migrated from Asia into the Americas several thousand
years earlier. Some of the earliest known archaeological sites in Florida are also among the most unusual anywhere in the New World, because they are
wet sites where anaerobic conditions have preserved
organic material that normally decomposes. For example,
at
years ago,
Windover Farms, near the eastern coast,
pond dating from be-
outside of TitusviUe, a burial
tween 7,000 and 8,000 years ago has yielded
40
MATUB.AL HISTORY July/August 2005
—
in ad-
and in what is now southeastern Georgia. Although they were somewhat unified linguistically,
speaking a dozen or so dialects of one language family, they were poHtically divided into as many as fifty
terior,
distinct chiefdoms.
The
Guale,
who
lived along a
and the Apalachee,
narrow
who lived in the panhandle, were both well-defined
chiefdoms. They were Unguistically distinct from the
Timucua and from each other. The Apalachee were
the most setded of the three groups, cultivating maize
strip
of the Georgia
coast,
and other crops in a weU-defmed territory bounded by the AuciUa and Ochlockonee rivers. Other in-
digenous groups lived outside the zones proselytized
inissionaries, particularly in the south of the
by the
Florida peninsula.
The
process of cultural extinction initiated by the
Spaniards was stepped up beginning around the mid1600s, as
Enghsh colonies became
established to
the north of Spanish territory. Instigated by the
lish
but carried out by their indigenous
ly Creeks), raids
allies
Eng-
(main-
were conducted, mostly against the
slaves. Then, early in the 1700s,
Guale, to obtain
EngHsh
Apalachicoln R:
colonial forces assaulted the Spanish mis-
sions. By 1706 the missions outside Saint Augustine
had been abandoned or burned, and many Indians
had been killed or captured as slaves. A minority of
Indians remained Spanish loyalists and retreated to
the protection of Saint Augustine, while others fled
to seek French protection in Louisiana, or disappeared into the wild frontier that was central Georgia and Appalachia. The diaspora effectively ended
Gulf of Mexico
La Florida
Apaiachee region
Guale region
Timucua region
name
thousands of years of regional cultural continuity in
Yui
Tribe
northern Florida and coastal Georgia.
- -
Modern
From the early 1500s onward, historical sources
document, in increasing detail, the effects of
European contact on the indigenous peoples of La
Florida. Such sources, however, are neither unbiased nor sufficient in themselves. Complementing
the historical data are the resources of archaeology
and my own specialty, bioarchaeology.
Bones, and details of their shape, including signs
of injuries and muscle attachments, can shed light
on a population's diet, disease experience, and even
life activities.
Teeth offer similar information: cavi-
1600
ca.
state borders
in what are
and southeastern Georgia.
Spain established a colonial presence principally
now northern and central
Florida
There the Spaniards distinguished three regional groupings
of indigenous peoples: the Apaiachee and the Guale were
each well-defined chiefdoms, but the Timucua were divided
into as
many
surement
as
is
fifty
separate chiefdoms.
nondestructive
—two
issues that arise in
DNA.
my disposal came from
designing studies based on prehistoric
The
skeletal collections at
cemeteries previously excavated by archaeologists
long ago
as
the 1940s. For
as
some cemeteries only the
and dental malformations indicate some-
enamel, or white portion, of the teeth was pre-
thing of the general health of individuals in the past.
served; the tooth roots, as well as the rest of the
My
research focused not on health, however, but
on two other kinds of data; demographics and microevolutionary change. My hope was to reconstruct patterns of genetic relationship and document
skeletons,
how
was examining were
and the remains
of only fifteen or so generations were present, it was
unlikely that any genetic changes I might find would
have had enough time to evolve through natural selection. I was not looking, as paleoanthropologists
do, for evidence of long-term adaptive trends, such
as the evolution of increased brain size. The genetic variation I would see would reflect patterns of migration and the process of genetic drift.
Migration, as geneticists define it, encompasses not
only the literal movements of new individuals into
or out of a group, but also any changes in mating (or
ties, tartar,
those patterns changed through time.
The
existing estimates,
which are based on human remains
the postcontact period,
on
sites
focused
on
had decayed
in the acidic clay soils. Thus,
my sampling,
measurements, and analyses
dentition,
whose form,
and, for
historical sources as well.
AH the estimates are subject to error, but they do provide a baseline for comparative purposes.
Microevolution, by definition, is any change in
gene frequencies within populations of a single species. Such changes appear over short periods of time,
whereas macroevolutionary changes, such as the rise
of new species, take longer. My approach to microevolutionary research is to measure skeletal remains, because they are widely available and mea-
fortunately,
is
strongly
influenced by genetics.
Because the populations
of the demographer is to determine the
size of populations and identify their members by age
and sex. For the indigenous populations, I relied on
task
and other evidence from archaeological
I
confined to
I
a relatively small region,
marriage) patterns that redistribute genetic variation
across the landscape.
For example,
groups previously married only
if
neighboring
among
themselves.
July/August 2005
NATURAL HISTORY
41
I
I
but then begin to intermarry, the variety of genes in
Second,
each group will increase, and the variation in genes
ability
wiU become more homogeneous, or evenly
across the two groups.
three population groups
spread,
portion of traits in the preceding generation. Drift
all three populations, yet the Apalachee appear to have
weathered them better than the Guale or the Timucua. The Apalachee population dropped by more than
is
comparable to the kind of sampling error that pollhave to take into account, and the smaller the
population, the greater the Ukelihood it will show up.
For example, if only one person in a small group had
all the genes for red hair, and he or she perished in
(in
no way
70 percent, from a precontact total of 30,000 to about
8,000 by the time the Spanish missions were aban-
tion), the
doned
in the early 1700s. But by the mid-1600s, the
Guale had already declined from several thousand to
several hundred, and the Timucua from more than
attributable to having red
—which would be an example of
group would lose the
150,000 to
natural selec-
of red
trait
all
genetic
one period to the next.
data showed that the stresses of
the postcontact period were almost overwhelming for
sters
hair
whole— combining
—and compared
as a
The demographic
drift arises
an accident
estimated the overall level of genetic vari-
variabUity froni
by chance alone; through purely random processes, the individuals in a group in one
generation may not reflect the full range and proGenetic
I
within the region
hair.
netic drift tends to reduce genetic variability
The
Ge-
when
than a thousand.
less
trends in genetic variability evident in
my
samples of the Guale differed sharply from those of
populations are declining
the Apalachee, and part-
and migration bet'ween
populations is hmited. As
a consequence, data on
ly explain the striking
contrast in the fate of
the
the genetic variability in a
<
population can provide
>
k
ulation size through time.
begins,
>
<.
timating changes in pop-
Among
creases as colonization
width
an independent way of es-
two groups.
the Guale, variability in-
length
then declines
rapidly after 1650. In
polar
contrast,
tooth
among the Apa-
lachee, variability does
The
measured were the
dental features
length and width of tooth
crowns for all four types of
—
teeth
incisors, canines,
premolars, and molars
illustration
on
[see
this page].
From these measurements
I
not change with initial colonization, but
I
could also calculate the
Tooth length and width, defined as shown
of length to width,
which
is
illustration,
largely
relatedness
among populations
as
it
increases dramatically
variation
and
is
in
—
each case
the most forward
however, the second incisor
is
and shape are both strongly
all, I examined 1 ,300 individuals, enough to have reasonable samples of people
living in the Apalachee, Guale, and Timucua regions
size
caused
sources vaguely note that
l<nown as the polar teeth, were measured. For the upper jaw
—
What
human
remains. The teeth least subject to nongenetic variation,
molar
1650.
the difierence? Historical
thor examined teeth from archaeologically excavated
(shown), the polar tooth
after
of Native Americans, the au-
in
incisor, canine,
the mouth;
in
premo-
epidemics ravaged the
eastern coast of Florida
and Georgia early in the
the lower jaw,
1500s
measured.
one aspect of
tooth shape. Tooth
—
essentially
contact; similar
ics
upon
epidem-
may not have exacted as severe a toll among the
much later, perhaps a century later.
influenced by genetics. In
Apalachee until
for three discrete time periods: late precontact (A.D.
sudden,
increase of genetic
The
immigration, apparamong the Guale
1300-1400), early mission period (1600-1650), and
late
mission period (1650—1706).
was primarily interested in two kinds of analyexplored how genetic variation changed
in each of the three population groups with time.
My reasoning was that if variation was decUning, so
was the size of the population, because the smaller
the population the greater the effect of genetic drift
in reducing variation. Conversely, if variation was
increasing, population was increasing as well, most
I
sis.
First, I
likely
because previously separate lineages or ethnic
groups were gathering together for mutual support.
42
the
by genetics. To study genetic
determined
lar,
ratio
in
well the ratio of length to width, an aspect of tooth shape, are
NATURAL HISTORY
July/August 2005
variability
early
reflects
ently
by
Most
likely,
outsiders
showing up in
their territory.
Guale groups that had suffered heavy
losses from the epidemics, as well as from conflict
with the Spaniards, were drawing together and being joined by other decimated groups.
The
subse-
quent dechne in variabiUty in the region, the result
of genetic drift, is a signal that their numbers then
steadily fell. In contrast, the Apalachee were still in
an earlier phase of transition by the time the mis-
and their population was dispersed.
of biological interaction among
the three ethnic groups in precontact times proved
sions
fell
The
overall level
relatively high. Intergroup warfare,
sulted in the capture of women
which often
re-
and children by the
victor of a violent encounter, helped ensure genetic mixing. Intergroup marriage and sexual unions
imdoubtedly also took place as a result of other forms
of ceremonial and social interaction.
During the early mission period, the Indians in all
three regions were converted to Catholicism and united under the banner of Spanish authority. Paradoxically,
however, the genetic diiferences among the three
regions
become more pronounced, not
By
less.
stricting small-scale intertribal warfare and,
re-
perhaps
by interfering with other forms of
less intentionally,
may have reduced the
social interaction, the Spaniards
—and
degree of genetic mixing. Ethnic boundaries
—may
therefore, perhaps, genetic ones
also
have been
shored up because the different groups were competing for access to European
power and
prestige.
After 1650, the region-to-region differences
shrink dramatically, a sign that mating had expanded
across language
and ethnic boundaries. The remnant
Christian populations had
cal
become
a single biologi-
By
population.
Three
account for that unification.
factors
local village populations
tell
to critically
First, as
low
levels,
people were forced to bend traditional rules regarding
who was
a suitable mate. Second, people
often choosing to migrate over longer distances.
were
Such
1
cally
750, the indigenous landscape of La Florida
changed.
All
had dramati-
the original tribes were gone, and their lands
were being settled by Creeks migrating southward along the
Flint and Chattahoochee rivers. The Creeks in Florida eventually
became recognized
as a distinct people, the Seminole. Before
those migrations, however, the Creeks themselves had arisen
from a conglomeration of various groups that had sought
central Georgia
and Alabama. The
population shuffling was hastened by Spanish at-
refuge
tempts to repopulate strategically important missions.
gest that an important constituent of the Creek population ac-
Finally, after
1650, England began competing in-
tensely with Spain for
New World
tually
in
descended from some of La
author's data sug-
Florida's original tribes.
dominance, en-
couraging indigenous aUies to carry out slave-raid-
an indigenous tribe that had existed for thousands of
ing expeditions against the Spanish-aftlhated
years in their region.
In that context,
tribes.
suggest, the tribes in Spanish Flori-
I
da minimized their internal ethnic, cultural, and Hnguistic differences.
The resident groups
tifiable as
most
in
La Florida
stUl
were iden-
Apalachee, Quale, and Timucua.
though,
interesting,
perspective, a new,
is
that
from
What
is
a biological
more homogeneous indigenous
population was emerging in Spanish Florida. That
named—and hence
—was then widely
when
nascent population, never
visible to us
in-
today
scattered
the missions were destroyed. The only Native
American groups that still retain their original identity today descend from a few Apalachee who, at
that time, fled to the
French Louisiana
territory.
Even
their
name was not
in-
digenous: they were referred to by English traders
as
Ochese Creek (now called the
Ocmulgee River); later they were simply called
"Creeks." During the early to mid-1 700s, some
Creek groups, principally from central Georgia,
moved down the Flint and Chattahoochee rivers into Spanish Florida [see map above]. With time, the
Florida communities, separated from the Georgia
Creeks by several hundred miles, evolved into the
Seminole, a distinct tribe that, like the Creeks themthe Indians living near
selves,
did not exist in
My own
name
in precontact times.
research does not dispute the arrival
Creeks from Georgia
Seminole. But
as
of
the ultimate origin of the
my findings give a new perspective on
the biological origin of the Creeks, and by extension,
With
was
Uved in
Florida's tribal areas vacant, the stage
set for
repopularion by Creeks,
who
Made up
of fracmred
populations that had congregated in the
Deep South
central
Georgia and Alabama.
sometime
languages.
in the 1600s, the Creeks spoke a variety of
They
constituted a
new
confederacy, not
the Seminole. The numbers of Apalachee, Guale, and
Timucua dropped during the mission period, and the
typical
assumption
is
that disease
was
at
the root ot the
decUnes. But those unhappy with the presence ot the
friai's
or Spanish
irulitaiy,
or imhappy with the in-
creasingly um'easonable labor quotas levied by the sec-
July/August 2005
NATURAL HISTORY 43
ular
government in Saint Augustine, may have sim-
ply fled the sphere of Spanish influence.
suggests
may
is
that the
What
"Creeks" in the Georgia interior
have included ethnic Apalachee, Guale, and
a nuanced distinction simply ignored or un-
Timucua,
recognized by contemporary European chroniclers.
Another clue is the location of the earliest settlements chosen by the Creeks or what I would call
—
—^who moved
the proto-Seminole
move
into Florida.
The
been well documented. In
part, it was an outcome of the Yamasee War of 1715,
between the Yamasee and the EngUsh in South Carolina, which worsened relations with the English.
At the same time, the Spaniards invited the Creeks
to settle in central and northern Florida, where they
could serve as a bufier between Saint Augustine and
impetus for the
land, vacant for only
that
has
If
I
am
two or three generations.
of the Seminole
right, the genesis
an
as
movement of
ethnic group does not begin with the
an outside population into Florida, but with events
that took place a hundred years earher. Gene flow
between previously separate groups was the first step
in forging a new identity. It was followed by the dissolution of earher ethnic labels and the shared experience in the Creek confederacy of Georgia. The
subsequent shared experiences in Florida and increasing isolation fi^om the Creek confederacy remaining in Georgia promoted the emerging Seminole identity. PoUtical unification, in the 1800s, then
came
in response to
American demands
nole governing council.
for a
Semi-
The U.S. government's pur-
pose was to hasten the Seminole's removal to lands
west of the Mississippi. After three wars, that goal
was nearly accomplished.
exception of
community of
With
Apalachee descendants who
today
the
the small
in
live
Louisiana, the ethnic groups inhabiting Florida at the
European contact have been conno longer spoken,
their customs no longer practiced. The legacy of the
Guale is particularly Hmited, perhaps reflecting their
early and rapid decline in the wake of the epitime of the
first
signed to history, their languages
—
—
demics. Prominently but erroneously
Apalachee Hved along the coastal plain
name
Chief Outina (center) and his warriors, depicted
in this
scene
artist Theodor de
belonged to one of the original tribes the Europeans encountered in the region. The Spaniards referred to this and
"
other tribes that spoke similar dialects as the "Timucua.
—
—
the engravings of the sixteenth-century Flemish
Bry,
Theodor de Bry
sources
made
A glance
the region inherently attractive.
at a
map of the
earliest settlements that
were destined to be Seminole, however, reveals that
the incoming groups were settling areas formerly
inhabited by Christian Indians, primarily Apalachee
and Timucua. In my view, then, another major factor affected the choice of setthng area: the pohtical
influence of the elite Christian, pro-Spanish Indians that had left La Florida and interbred with Creek
elites. There is even some historical documentation
that ethnic Apalachee had intermarried with Creek
elites in Georgia. Although they were only a minority of the Creek population, the Apalachee may
have been a key component. Their descendants
could have harbored
!
their tribal
commemorated in the East's great mountain
range, the Appalachians. The Timucua language family hves on in various modern place names, such as
the city of Ocala and Tomoka State Park, both in
alFlorida. The images of the Timucua themselves
come down to us in
beit fancifiil in many respects
is
of sixteenth-century Florida by the Flemish
the English colonies. Finally, the rich Florida re-
44
^because the
NATURAL HISTORY
July/August 2005
ties to
the traditional
home-
[see illustration
gravings were based
Moyne
on
de Morgues, an
on
this
page].
artist
The en-
the drawings of Jacques
Le
who accompanied
the
artist
brief French occupation of La Florida.
Members of the Creek and Seminole tribal conwho compUed with the provisions of the
Indian Removal Act and endured the hardships of
federacies
Indian Territory are represented by their descendants
enrolled in the federally recognized
Muscogee
The de-
(Creek) and Seminole nations of Oklahoma.
scendants of the small number of Seminole who elud-
ed capmre in the Florida swamps are now several
thousand strong. They formed a constitutional government and achieved federal recognition in 1957.
A closely related, but much smaller renegade group,
the Miccosukee Tribe, has enjoyed separate federal
stams since 1961. Like most up-to-date tribes, they
all
have
ing,
Web sites
that recount their histories, assert-
one by one, remarkable
stories ot survival.
D
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LAND
THIS
Sand Trap
Confined
to
mountain
a
valley,
windhloum sand
has piled up into towering dunes.
By Robert
H.
More
Mohlenbrock
than
a
hundred miles
long and fifty miles wide,
the San Luis Valley Hes
within the Rocky Mountains of
south-central Colorado and northern New Mexico, bordered on the
west by the San Juan range and on
the east by the Sangre de Cristo
range.
Dominated by rubber
rabbit-
brush and grasses, the valley shares
its name with San Luis Creek, a
stream that flows through its north-
Rising
as
high
as
750
above the
feet
valley floor, they are the centerpiece
Bordered by the Sangre de Cristo Mountains
of the Great Sand Dunes National
(background), windblown sand dunes rise
Park and Preserve.
as high as 750 feet
Through volcanic action the San
Juans began to form about 35 million
Valley floor.
and the Sangre de Cristos
were rapidly upUfted beginning about
hard time taking hold. Plants that do
19 million years ago. Rain,
Blowout grass and lemon scurf pea
are two species that can send out
roots and rhizomes several feet into
years ago,
—beginning about
—
and
years ago
away
at
vi'ind,
1.6 inilLion
ice-age glaciers chiseled
the peaks. Sand, gravel, and
were washed into the
valley, leaving behind lakes
containing sand and silt.
clay
During dry
periods, these
lakes shrank or disap-
become
above the San
Luis
established often get buried.
the shifting sands, thus ensuring bet-
South and west of
dune field is a flatter, more vegetated zone known as the sand sheet,
and today that is the main source of
additional windblown sand.
ter stabilization.
the
peared, and prevailing
southwesterly winds blew
Dunes come in various shapes.
clouds of sand from the
Barchans are crescent-shaped
dunes that creep slowly across the
dry lakebeds across the
valley.
Sand
heavy for the
ly
sand sheet,
zone adjacent to the dune field.
Prairie sunflowers brighten the
a relatively flat
landscape
grains too
wind
beyond the
crest
half.
terway, however,
is
the
Rio
Gi'ande,
which
originates in the San Juans
and flows through the southern part
of the valley. The configuration ot
the two mountain ranges and the
ceaseless action of wind and \vater
have bestowed upon the valley the
tallest sand dunes in North America.
The windward
46
NATURAL HISTORY
July/August 2005
the leeward side.
is
the convex side
end
square miles
helped trap the sand
and
pile
it
in-
on the
region near
its
midpoint.
reason they are so concentrated
here
is
that several small streams help
capture and return sand
zone. In the dune
blown out of
field,
the sand
continually shifted back and forth
by the wind, and vegetation has
to
dunes
a
end
to
form
also join
transverse
—rows of sand
that
run perpen-
dicular to the direction of the wind.
Parabohc dunes are formed when
wind causes a blowout, that is,
begins to gouge sand out from
the
around
thirt)'
eastern side of the
One
is
side
mulated near the base of
the mountains. Occasional
strong northeasterly winds
The dunes cover about
this
blown over the
of the crescent. Barchans can
also
valley, in a
is
down
of the
slides
Sangre de Cristos accu-
in the valley
The more prominent wa-
sand
to ear-
to dunes.
ern
as
top and
a patch
weakened
its
of vegetation that has
The excavated
grip.
is slowly blown forward, but the
sand on either side of its path remains
sand
by other vegetation. The
forward-moving pile forms the
"nose" of a parabola, while the anchored vegetation left in place on either side forms two trailing arms, ofstabilized
San
yS
Luis Cree/c^Uj,
*vs
:5iS=,
Great Sand Dunes '^-^ . "^
National Park -^gfY*^
'^^^
^f^
and Preserve
1/
}
^
FOR VISITOR INFORMATION, CONTACT:
ten stretching behind tor long distances. Star dunes,
with arms that ex-
Rio Grande National
Forest to
the national preserve.
The
form
tend from a central point, torm
extends up the slopes ot the Sangre
where the winds pummel the sand
from several directions.
de Cristos, providing numerous
niches that enhance the biological di-
The dunes were
first
protected in
1932 by the estabhshment of Great
Sand Dunes National Monument,
which embraced fift\'-rune square
rmles. The monument remained essentially the same size until 2000,
when Congress authorized an expansion to create the Great Sand Dunes
National Park and Preserve. The first
major addition was the transfer of
about
square miles of the
sixt\'-five
Dune
In
the dune
field,
mainly where
it
versity in the preserve. Streams
Although the winds
bugseed, rush skeleton
and Russian
thistle (a
plant,
nonnative invader).
photographs of the area taken in
1936 with conditions in 1990 and
emeritus of plant biology at Southern Illinois
row-leaf Cottonwood, quaking aspen, and
and Woods' rose are shrubs that oc-
Among
the grasses and herbs are Ken-
field horsetail,
seal,
Marsh Most of the wetland species are commonly found in marshes in many other parts
Among them
grass, bluejoint grass,
bulrush,
are American
common
common three-square, cowbane,
fringed willow-herb, hardstem
marsh hedge
nettle,
marsh
skullcap,
needle spikerush, pinkweed. Rocky Mountain
coyote willow, nar-
Nevada bulrush, and scratchgrass have a
more restricted distribution, westward from
western Kansas and Nebraska.
Mountainside The predominant trees are
Ponderosa pine.
and white fir.
Such species as golden currant, mountain
mahogany, ocean spray, roundleaf snow-
and yucca.
lined with such trees as
University in Carbondale.
wheatgrass, starry false Solomon's
spikerush,
Streambank Large and small creeks are
professor
Douglas
nodding buckwheat, rubber rabbitbrush,
through early September.
is
tucky bluegrass, nodding brome, slender
manna
late July
trumpet goose-
Robert H. Mohlenbrock
cur here and there along the streams.
of the country.
from
did note,
dramatically smaller.
leaved penstemon, needle and thread,
sunflower brightens the
They
and scattered ponds had become
catseye, narrow-leaf gromwell, narrow-
vivid yellow
dune masses were
memory. Forest Service scientists E. Durant McArthur and
Stewart C. Sanderson compared
and western yarrow.
Prairie
that the
relatively stable.
not wrought substantial changes in
living
The vegetation in the sand sheet is made
up primarily of grasses known as sand
dropseed and sandhill muhly. Among the
other species are broom groundsel, James'
sand sheet with
found
however, that nearby marshlands
berry,
rose, hairy
are continu-
reshaping the dunes, they have
ally
mon
and lemon scurf pea. Other species
are burr ragweed, crown-leaf evening prim-
www.nps.gov/grsa/
small marshy areas within the park
thinleaf alder. Skunkbush,
plants are blowout grass, Indian rice
and Preserve
11500 Highway 150
Mosca, Colorado 81 146
719-378-6300
and
provide additional habitats tor plants.
grades into the sand sheet, the most com-
grass,
Great Sand Dunes National Park
preserve
iris,
swordleaf rush, valley rush, two spe-
cies of buttercup,
and two kinds of arrow-
grass. Blue lettuce, Douglas'
knotweed.
fir,
pifion pine,
Rocky Mountain
berry,
rich
juniper,
and wax currant make up the fairly
A grassy ground
shrub community.
layer of blue grama, littleseed ricegrass,
mountain muhly, and mutton grass
is
punctuated by wildflowers that include
beardtongue, dainty
gilia,
Fendler's rag-
wort, flatspine stickseed, hairy golden
aster,
hoary aster, James' buckwheat,
pygmy
flower rock jasmine, sanddune
wallflower,
tall
tumble mustard, and three-
toothed groundsel.
July/August 2005
NATURAL HISTORY 47
BOOKSHELF
By Laurence A. Marschall
live in
An
Odyssey of Ecological Invasion
by Alan Burdick
Farrar, Straus
and
Giroitx,
the British
Isles;
Asian long-
horned beetles, which infested New
York City maple trees in Brooklyn in
Out of Eden:
the mid-1990s,
now
threaten the trees
of Central Park; visitors to Hawai'i who
marvel at the variety of flowers in the
2005;
$25.00
tropical island paradise are Hkely to
Standing
in a lush forest
on the Pa-
of Guam, science writer
Alan Burdick is haunted by an eerie sicific island
Not
lence.
a single warble, tweet, or
—
be
were when they emerged, millions of
years ago, from the floor of the sea.
What's more, people are hardly latecomers to this process. The Polynesian
settlers of Hawai'i brought the first pigs
to the islands; centuries later, British
soldiers carried the first cattle there.
admiring plants that are visitors there,
too; most species of lowland flora in
Hawai'i were introduced by settlers in
Settlers in the
the past few centuries.
lantic,
nothing but the
buzz of insects, the passing hum of
a distant airplane, and the hushed rustle of the wind. Guarn's songbirds have
all vanished, victims of the brown tree
snake. An exotic predator native to Auschirp can be heard
New
American soil. Modern air
and ocean transportation has only
accelerated the process.
Burdick began
ficult,
on
the island,
museum
ecological purity at all. In most cases,
been going on for
no way
of knowing what an "indigenous"
ecosystem might look Uke.
Moreover, whether an invasion is benign or clearly
devastating, such as that of
Guam's brown tree snake, it
may be impossible to reverse. One lesson of Bur-
flycatcher,
now
exist
specimens or
tions in birders' guidebooks.
—
—
only
tat
as
Even some
the Mariana fruit
bat, for instance
are rapidly disap-
pearing under the attack of the resourceful reptile.
Guam may
be an extreme case of a
habitat devastated
grant.
But
it is
just because
by
a
hungry immi-
not uniquely vulnerable
it is
to another has
so long that ecologists have
illustra-
nonavian natives
perhaps impossible, to define
the leakage of species from one habi-
and the Mariana fruit dove, once widestuffed
He
"purest."
its
1,1
unannounced in a military vessel sometime around 1 949. Such birds as the bri-
spread
dick's
Box elder infested with Asian
longhorned beetles
(inset)
is
—
only
a
In 1988 the zebra mussel, once con-
Burdick
implies that even the
that challenges
fined to the lakes and rivers of Europe,
human invention. Would we know one if we saw
it? And if we did, would returning to
stand, preserve,
of a visiting freighter.
Today zebra mussels flourish throughout the Great Lakes, and can be found
in the Mississippi River and its tribuin the ballast tanks
taries, as far
south
as
New Orleans. Na-
clam populations in the Great Lakes
have been decimated, and other species
that compete for food with the mussels
are in sharp decline. Accumulations of
tive
zebra mussels clog municipal water systems, and have even been
sink navigational buoys
by
known
their
to
com-
"pure" Edenic
is
a process
NATURAL HISTORY
July/August 2005
that there
of na-
continuous dynamism
our ability to underand manage.
Spruce:
A True
Story
by John Vaillant
WW Norton & Company, 2005;
made their
made the journey. Insects and
worms hitchhike the ocean on bits of
is
as a "state"
of Myth, Madness, and Greed
way over the Bering land bridge to the
New World long before mercantile
$24.95
ships
flotsam,
coming ashore wherever
the
winds and currents take them. The capacity of plant and animal life to spread
what made it possible
newly emerging landmasses to de-
over the globe
velop their
I
The Golden
inherent in global ecology.
Siberian wooUy mammoths
Burdick points out that nowhere on
the planet does nature survive in an
Edenic state, unaffected by nonnative
48
a
be environmentally sound? Invasion
for
American gray squirrels now
is
it
bined weight alone.
invasions:
state
odyssey
no such thing
ture
a small, isolated island.
hitched a ride to Lake Erie, presumably
book, I sense,
uncover nature at
found that it was difthis
in an attempt to
Guinea, and nearby islands
Guam
dili-
lands to
in the eastern Pacific, the snake arrived
dled white-eye, the
World were
digenous plants back across the Atand in bringing the plants and
animals of their European home-
faint
traUa,
New
gent both in exporting American in-
is
own
indigenous forms of
and fauna in the first place. Without invasive species, volcanic islands
would have remained as barren as they
flora
To
the Haida people of the
K'iid K'iyaas,
not the
it
was
tallest
stiU a
Queen
was known as
"the elder spruce." It was
tree in the forest, though
Charlotte Islands,
it
giant by most standards,
standing 165 feet
tall
and measuring
more than twenty feet around at its base.
At about age 300,
it
was not the oldest
tree in the tribal area, either, for the
Queen
Charlotte Islands, which
lie
off
someone had
dent:
killed the spruce
carefully slicing into
at strategic
it
a
by
chain saw
tion
book
Into the Wild,
who
died in
the Alaskan wUderness while pursuing
way through and
another personal dream of environmental integrity. VaiUant's book is cut
cutting nearly
all
the
at its
wood
core to keep
just thick
it
upright.
Like the living dead, the tree was poised
ground with the
to crash to the
est
protagonist of Jon Krakauer's nonfic-
points around the trunk,
leaving a hinge of
enough
with
slight-
from the same
erary style that betrays
New
breath of wind.
As
cloth.
moves
it
smartly from scene to scene, with a
Yorker
magazine
lit-
origin as a
its
feature, the au-
thor wisely refrains from indulging in
arbocide,
soon emerged, had
The
been perpetrated by one Grant
it
Hadwin, a fortyish logger and surveyor
from the mainland who had become
futile
speculation about Hadwin's in-
he gives the reader arof an exotic landscape, along with illuminating disner
hfe. Instead,
resting descriptions
on
increasingly upset with the environ-
courses
mental
business,
tries
on
effects
of the big timber indus-
coastal forests. In a
message he
sent to the local newspapers,
Hadwin
plant genetics, the timber
and the clash between native
culture and corporate capitahsm. His
book is one to ponder and to savor.
referred to the spruce as the "pet plant"
of the logging companies. Speaking to
reporters, he claimed to have no animosity to the native Haida, who venerated the tree. Nor, he insisted, was he
"Golden Spruce," now gone, was once a
beacon of the forest.
the central coast of British Columbia,
are
home
still
cient stands
even
after nearly a
What was
was
by
its
some of the most anof timber on the continent,
to
its
century of logging.
remarkable about the spruce
lambent yellow, caused
genetic mutation that affected
color: a
a rare
ability to
make
The unfoliage among
chlorophyll.
usual brightness of
its
the dense greenery of the Northwest
made
seem to glow with its
and visitors not familiar with the Haida mythical name always referred to it as the Golden Spruce.
For as long as anyone could rememrainforest
own
inner
it
light,
Golden Spruce had stood not
from the shore of the Yakoun River,
which runs through the center of Graham Island. A local timber company had
set aside a small area of uncut timber
around the tree, partly as a recreational
resource and partly as a gesture to environmentalists. But sometime between
January 20 and January 23, 1997, the
Golden Spruce came down, crushing
the undergrowth around it and hitting
the ground with one end hanging over
the bank of the Yakoun. Although no
one saw it tall, the cause was soon evi-
Hadwin, was the
notion that protecting a few isolated
patches of wildness would make up for
the wholesale rape of old-growth
The Elements of Murder:
A
Oxford University
insane. Insanity, to
forests.
"When
society places so
much
on one mutant tree and ignores
what happens to the rest of the forest,
value
it's
not the person
who
who
points this out
it
that way.
To
the Haida, the felling of the spruce
was comparable to the destruction,
for New Yorkers, of the Twin Towers.
Throughout Canada, timber barons and
environmentahsts alike
2005;
Press,
S3 0.00
My
idea of bHss in the
summer
chair, a
is
a
dog days of
comfortable lawn
cool drink, and a stack of mur-
der mysteries. For those with similar
criminal frxations, here's a thick
of nonfiction that might also
should be labeled."
But few people saw
History of Poison
by John Emsley
condemned the
wanton destruction and called for swift
But Hadwin never went to trial.
A few days before his scheduled ap-
justice.
book
fiU the bill:
a natural and social history of poisons,
by the former Science Writer in Residence at the chemistry department of
the University of Cambridge. John
Emsley book includes more than anyone but a fiend would want to know
about the uses and abuses of antimony,
arsenic, lead, mercury, and thallium,
along with information about a host of
's
commonly
ber, the
pearance, he set out from the mainland
elements
far
in a kayak,
presumably intending to
paddle across the treacherous Hecate
Strait to his court appearance on Graham Island. A few months later the remains of the kayak and a few of his personal possessions were found on an
Alaskan beach, 450 rrules from his point
of departure. Hadwin s disappearance,
like his strange and desperate act of
protest, remains cloaked in the mists of
under the proper circumstances, no less
deadly: barium, chromium, selenium,
and tellurium among them.
The danger of these poisons, well
50
I
NATURAL HISTORY
July/August 2005
win
impossible not to compare
to Christopher
to pathologists,
Had-
McCandless, the
is
ingested but,
that their ef-
fects
can be both cumulative and insid-
ious.
When such toxic elements are en-
vironmental, particularly
when they oc-
cur in one's everyday surroundings, one
can be slowly poisoned without ever be-
coming aware
the Northwest Coast.
It's
known
less
Substances
that
now
something
is
wrong.
considered highly poi-
sonous were once even prescribed
as
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"Weaver has made
it
possible
for everyone to share in this
great intellectual adventure."
—Riccardo Giacconi
THE VIOLENT
Cosmos
Kimberly Weaver
foreword by Riccardo Giacconi
astronomers use color
to understand extreme events such as
supernovae
galactic collisions,
and
eruptions,
$35.00
steller
implosions.
hardcover
a chloride
of mercury, was
used well into the 1950s
known
Joyrides through the X-ray
how
Calomel,
teething
UNIVERSE
Reveals
home remedies, simply because they had
no apparent negative effect and their
medicinal effect was beneficial.
powder
as a so-called
for babies, since
to soften the gums.
The
it
was
babies'
was a mild case of
mercury poisoning. At its most severe,
mercury poisoning causes teeth to fall
out. Because mercury also attacks the
nervous system, even the low doses in
the teething powder no doubt affected
the mental development of miUions of
smiling babies. And smihng adults, too:
reUef, unfortunately,
President Lincoln supposedly ingested
Then again, ffyou're losing your hair,
It may be more than bad
watch out!
genes
—
especially if your
tingling feehng, or
feel
body
has that
your hands and
numb from time
feet
to time, or you're
Someone who
having trouble sleeping.
from your demise may
have read The Pale Horse, a classic
Agatha Christie, whose villain used
thaUium salts to knock off his victims.
would
profit
ThaUium
ions are dead ringers for
potassium ions, one of the metals es-
ThaUium, however,
sential to health.
way
does not function quite the same
When
potassium does.
Uum
too
much
circulates in the blood,
all
it
thal-
invades
the organs of the body, im-
pairing their operation, destroying hair follicles, muscles,
and nerves. Because
takes
it
time for thallium to get into
the
large doses
cells,
may pro-
duce no immediate effect. But
because it is not readily excreted, thallium continues to
build up long after the
fatal
flagon has been drained.
By
the time the victim begins
hallucinating, turns grayskinned,
becomes paralyzed,
and
it
dies,
to identify
may be
who
tardly deed, or
impossible
did the das-
when.
The Hst of the famous who
may have been poisoned by
J.J.
ASTRONOMICAL
ENIGMAS
Life
on Mars, the Star of Bethlehem,
and Other Milky
Mark
Way
Mysteries
R. Kidger
takes us
on a tour of the
solar system, addressing
an array of
fascinating questions
.
.
.
Kidger's
playful but informed style
book a joy
—
makes the
to read."
Publishers Weekly
i29.95
mercury in the pills he took as a laxative, which may have led to his reported
propensity to
hardcover
THE JOHNS HOPKINS
mood swings.
choice for
many
murderers, especially
who want to
conceal the very
existence of a crime. Has the skin on
your palms and the soles of your feet
been thickening lately? Have you been
weary, overly irritable, losing appetite
and weight? Are your eyes red and watery? Check that elderberry wine your
maiden aunts have been serving you,
or those bonbons that keep coming
from a secret admirer. You have all the
signs of chronic arsenic poisoning.
UNIVERSITY PRESS
1-800-537-5487
•
www.press.jhu.edu
1847
one of these devious toxins is
from Pope
a long one,
Clement II to Mozart. Emsley has dug
up the dirt on these and a rogue's gallery
of lesser-known cases. Today, wth ana-
lytical
That same treacherous subtlety
makes poison the weapon of
the ones
"In 12 delightful chapters, astrono-
mer Kidger
Grandville, personification of cigue (hemlocl<), ca.
52
NATURAL HISTORY
July/August 2005
techniques that can routinely sniff
out minute amounts of toxins,
villains
can no longer count on getting away
with the perfect murder. But if the
golden age of poisoning is gone (replaced, to be sure, by other forins of
mayhem), in Emsley book it's stiU very
's
much
ahve.
Laurence A.
Supernova
M.iRSCH.iLL,
Story,
is
W.K.
T.
nuilior of
The
Sahin Professor of
Physics at Gettysburg College in Pennsylvania,
and
director
of Project
CLEA,
which produces
imdcly used siiindatioii software for education in
astrouoiiiy.
tion prize
He
is
the
2005
ii'inner
of the Educa-
of the American Astronomical
Society.
mil ,one
at a time, to
match
nature.net
lllRIISIIIIillSIKllllipilS
ganized
g ov/pa eo/ctl/reso urcebeyond.htm I).
Out
Chill
time line (www.ngdc.noaa.
as a
I
On
the
view
By Robert Anderson
a
home
down
page, scroll
to
time chart of Earth's ice ages.
You can
on "About CTL," on
click
menu at the top of the page, to
learn how best to take advantage of the
site's many resources.
the
Summer
heat getting you
Then imagine
machine
down?
setting
your time
for a geologic era
more than
half a biUion years ago,
when
the entire
globe, not just the polar regions, was
In the 550 million years since the end
of the Precambrian
geologic
era,
enveloped in ice. Average surface temperatures reached minus fifty-eight de-
processes have melted, twisted, reori-
been
kicking the "snowball Earth" hypothesis around for more than a decade, ever
much of the oldest rock record. Yet
through painstaking detective work,
since the discovery that glacial features
map of the
occur in Precambrian rocks over a wide
Cambrian explosion. To view
According to the
theory. Earth was exposed to as many
titled
grees Fahrenheit. Geologists have
area of the planet.
as
four freeze-over episodes, each fol-
lowed by melting brought on by volcanoes [see "The Longest Winter," by
Gabrielle Walker, April
2003].
Some sci-
entists
think the catastrophic chmate
swings
may have
ented, deeply buried, or destroyed
geologists have assembled an accurate
continents
at
the time of the
a
map
"Late Precambrian Superconti-
Elevette^" has
more choices
in styles, finishes,
nent and Ice House World," return to
options and price levels.
the "Paleomap Project" (www.scotese.
parts warranty no one can beat. Call us today
com/),
and from the
list
at
the
of the
left
home page, cHck on "Earth History."
Once there, click "Precambrian" on the
menu at the left of the page.
It
comes with
also
a
toearnmoe||^Q||SjAjOR
COMPANY OFJl^AMERICA
ip
DEPT. 3
www.inclinator.com 800-343-9007
.
sparked the so-called
Cambrian explosion, the geologically
sudden evolution of complex animal life
on Earth.
Try the snowball Earth theory on for
size by listening first to a five-minute
audio explanation that covers the basics, at
the
dio online
North Country PubHc Rasite
(go to www.northcountry
publicradio.org/news/natural.php
scroll
down
Return
to
and
to "Natural Selections:
Snowball Earth").
Or go
straight to a lengthy but informative
text, " 'Snowball'
Scenarios of the Cryo-
genian," posted in
2002 on an impres-
Joseph L. Kirschvink, a geologist at
Caltech specializing in paleomagnetics, coined the term "snowball Earth"
in 1992.
At
his
Web
site
you can access information about past and present projects of Kirschvink and his laboratory group.
his site
good
sense of the extreme
the theory, visit the
map Project"
the menu at
click
down
site
of the "Paleo-
(www.scotese.com/).
the top
by
left
From
of the page,
on "Climate History."
Scroll
here to the chart titled "Ice
House or Hot House."
on the blue hypertext "iitpw.mov").
The
Internet
also the place to
is
At the
for dissident views.
site
Institute for
go
of
Space
an
article
by
geologists at
Columbia University.
They simulated
climatic conditions
two
during the
late
Precambrian
era,
and
found that, even in worst-case scenarios, with reduced solar radiation and
low levels of greenhouse gases, the
oceans would have remained ice free
They dubbed
Administration has posted information
Robert Anderson
about
writer Ui'ing in
in a highly accessible form, or-
Web
Studies (www.giss.nasa.gov/research/
model "slushbaE
it
Murals
by Green River Stone Companij
about the time of the Cambrian ex(scroll down the page and click
cHmate
history is a fascinating topic, and the
National Oceanic and Atmospheric
Earth's
DUMBWAITERS
plosion
briefs/sohl_01/), you'll find
a
LIFTS
One fascinating feature
terozoic/Snowballs.html).
To get
WHEELCHAIR
is
NASA's Goddard
climatic fluctuations conjectured
Fossil
•
an animated reconstruction of continental displacements at
of
Web site called "Palaeos: The Trace
of Life on Earth" (www.palaeos.com/Pro
sive
(www.gps.cal
tech.edu/users/jkirschvink),
RESIDENTIAL ELEVATORS
near the equator.
their
Our private
Wyoming
lies
in
..fiuinij
Southwest
at the bottom of an
ancient lake. Fifty million years ago,
fortuitous conditions
combined
To
preserve fish perfectly.
Our technicians remove excess stone
hand tools to reveal the
using fine
pristine fossils in stunning detail. The
finished fossil mural
is
a snapshot
in
time, a timeless piece of natural art.
Earth."
is
a freelance science
Los Angeles.
www.greeariverstoae.com
435-753-4069
July/August 2005
NATURAL HISTORY 53
LETTERS
(Continued from page 10)
itive
accurate depictions of a wader.
including those prim-
feel strongly that
have produced
results
supporting an
Asian origin for the group.
As
for Deinosuchus, that animal
mean
The
to the tale [sic]!' These men, with
backgrounds in surveying, were not
supposed human is articulated more
Uke an amphibian than a mammal.
Early New Mexican artists were
Asian taxa in their study would
was
superb
at
depicting natural history, so
given to exaggeration, so there
I
ian,
but to our knowledge, paleontolo-
doubt they would represent humans so
oddly. Why was this image interpreted
gists
have yet to recover stomach con-
by Ms. Mayor
undoubtedly one
big,
crocodil-
as
predation
on people?
John M. Marzluff
tents that include juvenile tyrannosaurs.
is little
reason to doubt their measurements.
Lewis and Clark seem also to have
irdstaken the remains of a prehistoric
reptile
or dinosaur for those of a
fish.
Bruce Meyers
Paulsboro,
New Jersey
University of Washington
Mistaken Identity?
Adrienne Mayor's supposition, presented in her article "Tales
From
Seattle,
is
the
But
certainly reasonable.
I
found some of her supporting evidence unconvincing. On page 56, the
picture of the enormous New Mexican bird snatching up a "human" was
particularly troubUng.
I
would
suggest
image actually shows a wading bird with a frog. The downwardcurving bill of the bird, the small
head, and the swollen knees are all
that the
Adrienne Mayor notes that Native
American tribes mistook prehistoric
Marzluff is located
dinosaur remains for the remains of the
is
monsters that populated their myths.
photo caption incorrecdy
But they may not have been the only
viewers have agreed with Mr. Marzluff
at
Puerco Pueblo in
Petrified Forest National Park,
in Arizona, not
which
New Mexico,
states.
as
the
Some
ones to misidentify the remains.
that the carving depicts a frog in the
The Lewis and Clark expedition
recorded an incident on September
beak of a wading bird. The long beak
might support this view, but the large
size of the frog seems unrealistic.
10, 1804, that has
never been ex-
plained. Their journals state that
when
passing through present-day South
Dakota, the party "found the back
bone of a
Greg
•OSMlCi^
The
M.
replies:
petroglyph mentioned by John
Badlands" [5/05], that fossils may
have influenced human legends and
myths,
Adrienne Mayor
Washington
fish,
F.
45
feet long, tapering
Reinking's
"Cosmic Legacy"
Other viewers have argued, though,
be a struggling human carried by a giant bird.
Teratorns, which are now extinct,
were large raptors that co-existed
with humans in North America and
snatched up prey with their long
that the victim appears to
beaks.
I
chose
learned that a
this
rock
Hopi
art
elder
ated the drawing to old
Hopi
tions about giant birds that
takes
you on a journey
that begins
with the origin of time, matter and
reality,
follows the formation of the
cosmos,
life,
and humanity, and
because
had
I
associtradi-
used to
swoop down and fly off with Hopi
children. His comments are documented in my book.
Bruce Meyers
is
correct in point-
ing out that Lewis and Clark's mea-
presents our interpretations of
surements of the immense spine and
existence and uhimate destiny.
ribs
were probably accurate. At the
time of the discovery, in 1804, dino-
The motivated reader \\ ill
realities
investigate
tlie
and consequences of cosmolog}
quantinn ph>'sics. biological exohition. cogniti^
science, and
r
\
scientific perspectives
human histors from liisloric and modern
with timeless philosopliical insights.
Scientific American. com best seller
were unknown. The locaHty
and dimensions of the South Dakota
"fish" have led paleontologists to
guess that the creature was a long-
saurs
necked plesiosaur or a serpentine
mosasaur. Fossils of both of these
Mesozoic marine reptiles are abundant in that region.
Skeptical Inquirer science best seller
Natural History welcomes correspontjikc
a quick tour of the Universe from the beginning
'inCf'and
beyond''
Mcnsa
of creation
to present
dence from readers (nhmag@naturalhistory
mag. com). All
Bulletin
letters
should include a
daytime telephone number, and
-
ifce at
!
your local bookstore or online at Amazon.com and Barnes
& Noble
may
be edited for length
and
all letters
clarity.
1-^0-882-3273.
^ 9," h^dcOver (updated lid P™ting released July 2004)
or contact Vantage^^Press at
i
,
:,»
(;
:~
;ii.,<M.-^.,-^
/;"
54
NATURAL HISTORY
Ju/y/August 2005
PENTAX
OUT THERE
Britten your adventure.
DCF SP BINOCULARS
Not Dead Yet
A
dying star
By Charles
is
caught flaring hriejly hack
most people see a con-
stellation referred
to as
Sagitta, their first inclina-
make the
tion is
word "Sagittarius." Not so fast. The latto add four
is
to
life.
Liu
When
ter
8x32, 8x43, 10x43, 10x50, 12.5x50
letters to
indeed the famous archer, one of
the remarkable objects that
these celestial stick figures.
outstretched
make up
Near the
arm of Sagittarius,
for in-
of our Milky Way,
some 25,000 light-years from Earth.
There, invisible to all but the most spestance, lies the center
the twelve constellations of the zodiac.
ciaHzed telescopes, lurks a black hole
But
milUons of times the mass of the Sun
Sagitta, the arrow,
constellation in
its
own
is
an ancient
right. Its stars
[see
"Peering at
tlie
Edge of Time," by
Fiil-
Nitrogen-filled
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Limited lifetime warrant/.
John
R.
Thompson, The Center Cannot Hold, 1993
form a diminutive but distinct flechette,
sandwiched between AquUa, the eagle,
and Vulpecula, the fox. According to
some versions of sky lore, Sagittarius
accidentally shot the
wayward
Sagitta
vio Melia, June 2003]. Sagitta harbors
nothing quite so dramatic. Yet one of
its stars has achieved a kind of minor
celebrity as a stellar corpse that has ap-
parently risen from the dead.
while aiming
at nothing in particular.
Others say the Greek hero Hercules
fired Sagitta at a vulture that was tormenting the captive Titan Prometheus.
Of course, none of our ancestors
who recounted those myths had the
sUghtest clue about the real identity of
About a bilHon years before a sunHke
star "dies,"
or stops generat-
ing energy via nuclear fusion, it becomes a red giant, growing dramatically to a
hundred times
its
original
(Continued on page 58)
Ju/y/August 2005
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(Continued from page 55)
as the red-giant phase
as tens
diameter. Then,
tle
ends, the star blows ofFits outer layers,
flicker
giving
rise to
an expanding gas cloud
called a planetary nebula [see "Ghosts
of Suns Past," by Charles Liu, March
2004].
The
planetary nebula, in turn,
swells in size
at
and drops
most another 100,000
ing the remaining
of millions of degrees. For
while
back into
stellar
a lit-
may even
the core
at least,
hfe as a giant
new energy with new
of nuclear fusion.
Alas, such a "born-again" giant can't
last long, because the core is, in esstar,
generating
flares
in density for
years,
stellar
A
expos-
core
"born-again " giant
can't last long.
That core becomes a white
dwarf the most common celestial cadaver visible in the sky. The white
dwarf usually radiates its leftover heat
into space for billions of years, and it
sence,
slowly fades to black.
out of gas within
however, seem to heed the counsel of
Dylan Thomas; "Do not go gentle into that good night." According to the
theory of stellar evolution, the temperature in the
ate wildly,
stellar
core can fluctu-
and sometimes spikes as high
star's
overall brightness
and temperature have changed dramatically through the years, one component
of the FG Sagittae system has been shining more or less steadily at a temperature
of about 1,200 degrees F (650 degrees
Celsius). That's roughly hot enough to
melt aluminum, but substantially coolof any
active nuclear fiasion.
—
dwarfs,
his colleagues discovered
though the
er than the core
at its
center.
Some soon-to-be white
Gehrz and
that,
star undergoing
Gehrz and his col-
leagues conclude that, besides giving
running on fumes. Without
a
substantial fuel source to sustain fusion,
a
nuclear re-ignition of this kind runs
a
few centuries, and
rise to
clouds of obscuring gas,
tae
powering
is
peppered with carbon
surface, has
dwarfhood. But during
to fusion-powered Ufe,
for the past decade.
brief return
interaction
its
with the surrounding cloud of gas
creates a fascinating astronomical lab-
oratory for the study of stellar and interstellar processes.
The
star
FG
Sagittae, a highly vari-
able star in Sagitta, seems to be a case in
point.
FG
past thirty years the
has dropped firom
He
star's
1-5. In the
less
than 10,000 de-
though its brightness has changed
erratically firom year to year. As with an
grees,
basis
of the
—
grease-choked diesel engine strugto start
back up, the
Sooner rather than later the
burst of
star's eflibrts
born-again giant into
cease.
surface, astronomers
must look
at
radiation in less obscured wave-
lengths, such as infrared light.
A research team led by Robert A.
Gehrz of the University of Minnesota
in MinneapoUs has now done just that.
Recendy the team pubKshed the results
of twenty years of monitoring the infrared properties of FG Sagittae with
Sagittae will change
The
again one.
The
dusty
stellar
stellar core,
dead-
a
wind
will
no longer ob-
scured by a thick, dusty blanket, will
turn once
stellar
—
FG
and
a
current
nuclear fusion will
cease,
smoke carbon atoms coughed
up from the fading stellar core. The
smoke absorbs the star's radiating heat
and periodically obscures the visible
light it emits. To see through the haze
and examine the goings-on near the
thick
new
from
If,
its
On the
Earth masses each year.
to restart nuclear fusion create puffs of
star's
star's
been glowing continuously
measured amount of emitted infirared
radiation, Gehrz's team estimates that
the wind is carrying between 1.5 and
7.5 quadrillion (1.5 to 7.5 X lO'^) tons of
stellar material away firom FG Sagittae
each second or about eight to forty
temperature
more than 30,000 de-
grees Fahrenheit to
old,
wind
They think
Sagittae Hes at the heart of a
planetary nebula called
gUng
dust.
originating from the
this dust,
the star heads back toward white
its
FG Sagit-
a strong stellar
more into a hot white dwarf.
models
as theoretical
renaissance of
FG
predict, the
Sagittae
lasts
few hundred years, the wind will
deposit thousands of Earth-masses'
worth of carbon-rich matter into the
a
surroundings.
star's
as
The carbon
atoms,
they cool down, could become seeds
for the buildup of interstellar dust
grains
—which,
in turn, could seed the
formation of asteroids, moons, planets,
and perhaps eventually even life as we
know it. Maybe the astronomers of the
twenty-fourth or twenty-fifth century
will
in
look toward
its
ings
FG
Sagittae
and
surroundings, the potential
of a
new and
see,
mak-
distant earth.
three telescopes equipped with infrared
photometers
ters.
one
58
NATURAL HISTORY
July/August 2005
One
—
in effect,
instrument
in Arizona,
is
photon counin Minnesota,
and one in Wyoming.
Charles Liu is a professor ofastrophysics at the
City University of
with die American
New
Yorii
Museum
and an
associate
of Natural History.
THE SKY
Mercury,
Venus
still
IN
AND AUGUST
JULY
much
near the
after their close
month, shines
brighter
encounter
late
western
evening twilight at magnitude 0.1 as
July begins. Mercury is less than a degree to the left of Venus; the two planets can be found just above the westnorthwestern horizon about forty minutes after sunset. During the following
two weeks the pair slowly separates, as
Mercury appears to pivot around and
below Venus. By the evening of the
13th, Mercury lies three and a half degrees directly below Venus, but Mercury
last
in the
appears only about half
did
at the start
as
bright
of the month, so
as it
rec-
I
ommend looking through binoculars to
By Joe Rao
August. Onjuly
1
the
Red Planet, bril-
magnitude —0.1, is exactly one
astronomical unit
92.9 million
miles
from Earth. Mars crosses the
liant at
—
—
constellation Pisces, the fish, this
month. On the 1st Mars rises nearly
due east just before 1 A.M., and it rises
about two and a half minutes earlier
each night thereafter.
During August the distance from
Earth to Mars shrinks to 62 million
miles. Mars's brightoess more than douit shines Kke a yellowmagnitude —1 only one
star, Sirius, shines brighter. Mars briefly
passes through the constellation Cetus,
the whale, from August 2 through the
bles as a result;
orange jewel,
at
The
planet
mid-August,
not visible again until
is
when
it
appears in the
east-northeast just before sunrise.
A
good time to look for Saturn comes on
the morning of August 18, when it
passes five degrees
above Mercury.
In July the Moon wanes to new on the
6th at 8:02 a.m. It waxes to first quar-
on the 14th
ter
fuU on the 21st
lite
at
wanes
7:00 A.M.
Our satel-
on the 27th
to last quarter
11:19 P.M.
On
;
11:20 A.M. and to
at
at
waxing
the night of July 17th a
Moon
gibbous
occults, or hides, the
bright reddish star Antares.
The
occul-
into the constella-
from parts of the far western and southern United States. Else-
sky.
tion Aries, the ram, for the rest of the
where, Antares seems to pass close to the
August 5 Mercury reaches inferior conjunction, passing between
Earth and the Sun. Thereafter the planet rushes up for a good dawn apparition during the latter half of the month.
By the 1 7th Mercury has brightened to
first magnitude and rises seventy-five
month. At the beginning of August
Mars rises just before midnight in the
east-northeast, and by the 31st it's ris-
Moon's upper limb. The best views
come between about 8 P.M. and 9 P.M.
on the 17th in the Pacific time zone, and
between about 1 A.M. and 2 A.M. on the
find the planet. After
midmonth Mer-
cury fades rapidly from the evening
On
minutes before sunup.
planet reaches
its
On the 23rd the
greatest western elon-
gation, eighteen degrees from the Sun.
At that point Mercury rises ninety minutes before the Sun and has brightened
further, to magnitude zero.
5th, before
moving
ing before 10:30 P.M.
1
Jupiter
dusk
is
as
low
in the west-southwest at
July begins, and just gets low-
er (and sets earher) as the
month goes
on. Jupiter remains in the constellation
Virgo, the virgin,
the planet
is
as it
was in June, and
a
cou-
ple of months now, but the planet consents to
showing
itself
longer in the twilight,
ever so slightly
as
the
summer
Although always bright, the
planet remains low in the sky all summer, as seen from midnorthern latitudes. On July 22 binoculars will help
progresses.
the constellation's brightest
star,
w^ith each passing night; planet
Spica,
and star
by about fourteen degrees as July commences.
In early August Jupiter sets about an
hour after dark, and just at the end of
evening twilight as August ends. The
planet continues moving eastward
against the stars toward Spica; the gap
between them
closes to six degrees
—and
by
the 31st.
More
show Venus's close pairing with the star
able
the approach of Venus to
Regulus, the
Jupiter.
stellation
little
king, in the con-
Leo, the lion.
star are just a bit
The planet and
more than one degree
though the planet
brighter of the pair.
apart,
is
much
the
Venus's apparition in August
—
is
On the
separated by
notable
1st
the
more than
two
notice-
planets are
thirty degrees,
but by the 31st they are within one and
a half
In August the
Moon
wanes
to
new
on the 4th at 1 1 :05 RM. It waxes to first
quarter on the 12th at 10:38 P.M. and
to full on the 19th at 1:53 RM. It wanes
to last quarter on the 26th at 1 1 1 8 A.M.
:
is
As July commences, sky gazers might be
able to see Saturn about forty minutes
an approach to Jupiter.
western horizon; the planet is about sev-
after sunset, just
The
Earth reaches aphelion,
its
point from the Sun, on July 5
farthest
at 1
:00
A.M.
The Sun is 94,512,036 miles away.
The
Perseid meteor shower
August. This year
comes every
peaks during the
it
predawn hours of the night of August
11th. The meteors are fast and bright,
and they often leave persistent trails.
From
and
a location free fr-om bright lights
tall
some
an hour.
seids
might see
hundred shooting stars
objects, an observer
fifty to a
The meteors
are called Per-
because they appear to shoot away
fr-om the constellation Perseus, a hero
of Greek myth. Because the Perseids
usually make their display around Au-
degree of each other.
changed from what it was in
June and July. The planet does make
scarcely
8th in the Eastern time zone.
moving eastward toward
are separated
Venus has been playing coy for
tation is visible
above the west-north-
which the Roman Catholic
Church recognizes as the feast of Saint
gust 10,
Lawrence, they have been referred to
as
the fiery "tears" of Saint Lawrence.
en degrees to the lower right of MerMars continues to approach Earth, and
so
it
brightens dramatically in July and
cury and Venus. Thereafter Saturn
swallowed up in the evening twilight.
is
Unless otheni'ise noted,
all
times are east-
ern daylight time.
July/August 2005
NATURAL HISTORY 59
Museum
At the
American Museum
Young
S
Naturalist
Awards 2005
A research-based essay contest for students in grades
to
www.amnh.org
Natural History (J^
y-12
promote participation and communication in science
Now
the
celebrating
its
eighth year,
Young NaturaUst Awards
recognizes the accomplishments
of students
who have
investigated ques-
Arizona. Over time, huge dry riverbeds
been an enemy of my household.
have been carved out of the earth by the
inates the
water.
They
most of the time, but
are dry
during a rainstorm they fdl up with
tions in the areas of biology, Earth
water. During the rainy season, the
science, or astronomy.
washes can have up
Every year, scientists from the
water in them, flowing very
American Museum of Natural History
travel far and wide on expeditions to
learn
more about
swiftly.
tiees are able to survive
and even
own
invited to
embark on their
to
home as
their
backyard or a local pond or stream.
plan
how they wiU gather information,
conduct outside research to leam more
about their topic and possible methodologies, observe their subjects,
analysis leads to conclusions that either
answer the original question or lead
to
further inquiry.
Included here are descriptions of and
from the winning
Full-length versions of the
essays
essays.
winning
and information on how to enter
Muwww.amnh.org/
the contest are published on the
seum's
Web
site at
y oungnaturalistawards
The Pantano Wash:
Investigating
an Ecosystem, by Daniel
Fried (Tucson,
Arizona; Grade 7)
Intrigued by a local wash, Daniel de-
cided to explore this ecosystem to leam
how plants
survive during flash floods.
"Most people have heard the old
ing,
'When it rains,
literally
true
where
it
I
pours.' This
live in
Effects
of Hedychium gardnerianum
on the Surrounding
in
Soil
and Native
Flora
say-
is
southern
ginger truly
is
environment? Maybe
bad
for the
ally
helps native plants."
actu-
it
Exploring Earthworms' Influences on
threat to the
Hawaiian rain
is
a
forest. Mali'o
investigates this plant further.
"Ever since
I
Robert
Among the lush variety of plants and
Remy encoun-
creatures in her backyard,
"The other day, in
Kahili ginger, an invasive plant,
Remy
Orleans, Louisiana; Grade 8)
tered several species of worms.
Volcano, Hawaii, by Mali'o Kodis
can remember. Kahili
ginger (Hedychium gardnerianum) has
and
record their findings. Finally, their data
excerpts
The
(Volcano, Hawaii; Grade 7)
After identifying a question, students
the ginger population.
never once wondered,
(New
expeditions, but their research can
be conducted as close
I
a Miniature Ecosystem, by
throughout the United States and
Canada are
grew up assuming that I was
plants in the wash, but grass, bushes,
thrive in this harsh environment."
Following in that tradition, students
I
ment by depleting
You might think that this would kill any
and
the natural world.
dom-
doing a very good deed for the environof
to 15 or 16 feet
sunlight.
It
ground cover and blocks out
my backyard,
I
slapped a mosquito that had just landed
on my knee and looked out at the spectrum of paper-thin, satin-soft flowers; the
bouquets of long, glossy green ginger
leaves;
and the young live
oaks.
My mind
—the wide
shifted
seemed
stretch of grass
Bmtbl<^b(l(Ull^'MI*blI
it
AM NH
PEOPLE AT THE
:
How big must seem to one
big to me.
nIgundmBieBMiBiaok
of the white, microscopic grains-of-sandwith-legs crawling
Does
in
Effluent
Fountain
Silvestri
around on the
fig ivy?"
Hills,
Arizona? by Christina
(Fountain
Hills,
Hills,
fill
"On my way to
school each day,
the Fountain Hills Fountain
Effluent water
is
I
and
I
pass
park.
and water the
at other
park.
fuU of animal and
is
times the water
gloomy, looking as
survive.
and Technology
over-vegetated ecosystem resembling
muck. This eutrophication
thick green
recycled wastewater,
the lake
At times the lake
life,
—
low
has greatiy reduced the amount of dis-
lake's cycles.
plant
l(X
Graphic Designer, National Center
for Science Literacy Education
Arizona,
a local
decided to explore the
lake. Christina
Dnn ty Eilu F tu; Ocwbn
Stephanie Fotiadis
Arizona; Grade 8)
uses recycled wastewater to
fill
l\(/J
Water Affect the Ecosystem
The town of Fountain
used to
A/f^
'""aN
if nothing
wondered why the town uses
I
The rehabilitation of Grovers Mill
Pond and Dam got underway, and I
wondered what impact the reconstruction might have on Big Bear Brook."
is
could
effluent water in a public area.
solved oxygen available to aquatic organ-
isms.
decided
The World through a Bat's Ear, by Sarah
Bayefsky-Anand (New York, New York;
Grade 10)
Sarah's curiosity about bats led her to
to investigate."
study
how they adjust their
Tidal Pools: Bacterial Variability
and
calls in cluttered
Marine
Holcombe
to orient themselves.
by Allison
Life Stability,
echolocation
environments in order
Stephanie Fotiadis
(Coto de Caza, California; Grade 9)
Allison sought to find out how ocean
The work that Stephanie Fotiadis
temperature and bacterial counts might
parents, and teachers every year, but
affect tidal pool
does
marine Ufe.
scenes. As the
whims of
El
five
Nino weather patterns can change
much of the native
fall.
a half years, she has
pages. "At the
I
may cause ambient ocean
temperatures to
and
am
Museum,
is
rewarding."
of my hypothesis for this expedition de-
for the creative direction
tional Center's
flux of the temperatures of
the ocean, as well as the resultant change
"During
Mill
Pond and
Reconstruction on Big Bear Brook,
by Eitan Paul (Princeton Junction,
Jersey;
Grade
to reconstruct
Dam were announced,
Grovers
Eitan won-
dered what impact the reconstruction
would have on a local body of water.
"In the 1800S early settiers in the area
built a 400-foot-long earthen
trap Big Bear
my fieldwork,
brown
and in
Brook
mOl. Over the years,
had watched
open
cluttered situations, so
I
and sediment
have spUled into the pond, creating an
of the Na-
sites,
including
calls
according to
I
hypothesized that in
Young
key
Naturalist Awards. She
member
re-
here
is
seum and
subject matter
thing new."
by
the American
Mu-
I
learn
some-
a
New York
is
City
restaurant connoisseur She has used
skills
to
produce
a tennis
as well as to teach an html
in
Harlem.
10)
The contents of these paces are provided to Natural History
We
at the
Outside the Museum, Stephanie
her
Alexander (McMinnville, Oregon;
—every day
an avid tennis fan and
the frequency for shorter wavelengths."
Elliot
many people
deal with such an array of
would adjust the features of their
calls, shortening the duration and the
intervals between calls and increasing
Grade
also a
so diverse and interesting.
interact with so
sponse to the degree of clutter, these
bats
The Dance of the Moons, by
is
of the production team for
each of these projects. "The work we do
pre-
would adjust their
the setting in which
dicted that these bats
dam to
for their grinding
silt
I
bats fly adroitiy in the
they operated.
9)
When plans
Mill
New
Web
Ology, Resources for Learning, and the
little
Dam
Web
really feel like
Stephanie has primary responsibility
pends on the
Impact Study of Grovers
I
creating something that benefits
people, which
Thus, the formation
in bacterial counts."
guided the
look of innovative educational
marine life. Even the changing of the
seasons
Designer for the
Education and Technology for the past
can raise bacterial counts.
feeding patterns for
Web
National Center for Science Literacy
humankind. Storm drain runoff after a
significant rain
seen by millions of kids,
Stephanie herself remains behind the
"Despite their adaptability, tide pools
are quite susceptible to the
is
Museum of Natural
History,
Web
site
seminar
Intrigued by Jupiter and
Elliot
moons,
its
Our cats live
I
o pily in a very
observed and recorded the posi-
moons
tions of the
so that he could
construct an accurate
i large, specially
model of the
equipped pen, but
inner Jovian system.
I
traveled about 50 feet for
"I
But
trip.
I
is
one place in the
system that puts on
a
show over
span of days or even hours
and
my field
its satellites.
hate to clean
I've
observed
worms
a time
—Jupiter
lit-
For years
ter pans.
solar
First discovered
still
the four smelly
looked over 300 million
miles. There
hap-
in the
compost piles in
the woods behind
by
Why
Galileo in 1610, the four innermost
our house.
moons of Jupiter seem
not borrow some
and
forth.
to shuttle
back
At certain times a change
visible over
an hour or
runs
could measure
less.
Since
is
it
disposal at an Iowa munitions plant
contaminated water sup-
in a rela-
have led
Longitu-
System, by Shannon Babb (Highland,
and serious health problems for
people living nearby. Mauree wanted
to find out what effects the industrial
runoff has had on local creeks.
"Over the past three years, I have
Utah; Grade
tested water quality using
fast,
I
tively short
it
period of time."
Troubled Waters:
A Six-Month
to a
ply
dinal Study of the Spanish Fork River
ii)
Daphnia
worms from the
woods and have them clean the cat
pans for me.' Having worms clean up
cat mess is my idea of how work
should be done."
A Search
and
magna, freshwater invertebrate crus-
Open
NCC 637,
Clusters:
by
Morgan MacLeod
taceans that are frequently used in
about their dwindling numbers.
water toxicology research because of
and
Shannon decided
their ability to signal stressful levels of
Morgan searched
Daphnia magna has a
water quality of the rivers that feed
pollution.
into the lake.
sensitive eye,
"For the past three years I have
been comparing the water quality of
track a
meaning that the eye
moving light source. This
knowledge helped
me
Armed
light-
will
to establish a
measurement of reflex, providing a
measurement of the effect of environmental stress on the nervous system."
NCC 381
(Cumberland, Maine; Grade
June suckers are a species offish
found only in Utah Lake. Concerned
to investigate the
Two
for Variable Stars in
Northern
12)
with a ten-inch telescope
a charge-coupled device camera,
the heavens in
hopes of finding variable
stars in
open-star clusters.
"Over the past two years,
I
investi-
gated variable stars with amateur
tele-
scopes and charge-coupled device
cameras.
First,
known variable
the light curves of
stars
were plotted using
a charge-coupled device attached to
Cot Cats? Cet Worms! by
(Prairieville,
Louisiana;
Eric
Grade
various camera lenses.
charge-coupled device was attached to
His dislike for cleaning out his
litter
cats'
boxes led Eric to experiment with
worm composting, with amazing results.
"The ultimate purpose of my experi-
ment
is
to find
an environmentally
friendly solution to animal wastes.
the rivers flowing into and out of Utah
Lake.
I
have been studying the rivers
to figure out
which one has the worst
water quality.
I
discovered that the
Spanish Fork River was the most polluted, [yet] only 12 miles
upstream,
where the Spanish Fork River flows
through Spanish Fork Canyon, the
river appears to
be healthy."
Environmental Effects of Industrial
RunofFon Daphnia magna, by Mauree
Point, Iowa; Grade n)
Gibson (West
Years of improper hazardous-waste
Then
Kimbrough
12)
the
the telescope for greater photometric
accuracy,
able star
and
a poorly understood vari-
named V377 Cas was
observed.
This research demonstrated that amateur
equipment could be extremely
fective in collecting
ef-
photometric data."
Museum
Events
American Museum
5
EXHIBITIONS
LAST CHANCE!
Totems
Natural History
A
lush photographic journey
from the Andes
to the
North American Jewelry Arts
English and Spanish.
of the Northwest and
This exhibition
is
made
in
www.amnh.org
The Grand Tour
Fridays
Tuesday, j/^, 6:^o-'j:}op.m.
8:]0,
Dynamic Processes
Hypnotic visuals and
rhythms take viewers on a
ride through fantastical
in the
Universe
possible by the
Tuesday, 8/2, 6^o-y:]o p.m.
generosity of the Arthur Ross Foundation.
Southwest
GLOBAL WEEKENDS
This exhibition celebrates the
beauty, power,
and symbolism
American
An afternoon of films,
tures,
Dinosaurs: Ancient
8/'j,
New Discoveries
and performances
tions' International
Through January
8,
2006
Global Weekends are
the mysteries of dinosaurs:
in part,
City of
they behaved, and
well as
how
like,
Day of the
possible,
by The Coca-Cola Company, the
New York,
and the
SonicVision
New York
provided by the
—
Inc.,
made
possible by
August's Hot Topics
The Search for Life: Are
Tuesday, 8/16, 6:}o-'/:]o p.m.
Alone?
Made
We
possible through the generous
support of Swiss Re.
Celestial Highlights
The Dog Days of Summer
Passport to the Universe
Tuesday, 7/26, 6:^o-y:]o p.m.
LARGE-FORMAT FILMS
The Summer Triangle
LeFrak Theater
Tuesday, 8/]o, 6:]o-y:]o p.m.
City
May and Samuel Rudin
Family Foundation,
is
generous sponsorship and technology
support from Sun Microsystems, Inc.
Hot Topics
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Dinosaurs: Ancient
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Neu^ Discoveries
accompanying education and
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This exhibition
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is
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tion with the
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Lila
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With author Vicki Croke
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The Ape
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in the Tree
Thursday, 7/23, 7:00 p.m.
Wallace-Reader's Digest
With paleoanthropologist
Endowment Fund.
Alan Walker
THE ART OF SC
beautiful measures
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Exploring Bolivia's Biodiversity
Art/Science Collision: The
Through August
Coney Island Museum
Originally conceived
Tuesday, 7/26, '/:00 p.m.
by Galileo, this elegant
thermometer is a
With curator Aaron Beebe
stunning combination
8,
200^
Starry Nights
Live
Jazz
Rose Center for
Earth and Space
\
"2"
FAMILY AND
CHILDREN'S PROGRAMS
DR. NEBULA'S LABORATORY
of art and science.
Suspended in a glass
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spheres rise and
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Starry Nights
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HAYDEN PLANETARIUM
PROGRAMS
TUESDAYS IN THE DOME
%
Virtual Universe
The CONTENTS OF THESE PACES ARE PROVIDED TQ NATURAL HiSTORY
fall
with the changing
6V THE
%j3is:^
AMERICAN MuSEUM OF NATURAL HiSTORY.
ENDPAPER
Messing
The
tion,
however, weren't nearly
natives,
about our
we
activities as
were.
By my
as thrilled
quick calcula-
anywhere between one and two dozen northern
A chorus of froggy
green frogs abruptly scattered.
About
From
"Eeeks!" gave voice to the general havoc.
By Dru Clarke
every
and dived toward the
safety of deeper water. Rocketing from the shoreUne
at least twelve feet behind me, one skimmed the surdirection
fi'ogs
face like an
leaped, skidded,
artfiolly
,
skipped stone before disappearing
underwater. Another perforined a clean, no-splash
"Do you know
fore in
"Nice
all
my
[said
Rat]?
friend, there
is
worth doing
messing."
[said
Mole],
life. Is it
It's
all
—
—
my young
half so
much
simply messing about in boats. Simply
Tlie
Wind
pond near our farmhouse
in the
swells
swelled
I
it
Willows
and
cedes with the seasonal rains, but the
downpour had not
From where I was standing
—
Olympic qualifier. A third simply jumped
up and fell, completing a comic cannonball.
After a moment the frogs burped to the surface,
a wet circle of improbable profiles. I pondered the
evolutionary forces that might have led them, despite their shared musculature and reflexes, to develop such a suite of diverse escape maneuvers.
Hearing the commotion, the mares and foals in a
nearby pasture galloped to the water's edge. They
stood dumbly gazing, then lowered their heads to
drink, keeping wary eyes on the floating phenomena. The frogs, apparently accustomed to such interlopers, were unfazed.
dive
a 9.8
straight
absolutely nothing
—Kenneth Grahame,
The
that?"
the only thing. Believe me,
nothing
as
never been in a boat be-
I've
so nice as
re-
last
by much.
could make out a
thick ring of sodden weeds that enclosed a smaller
of deep water.
But the water was deep enough to float my boat,
and my custom-made canoe, which weighed in at a
circle
Anxious for some action,
Sukey and
I
paddled
over to a pole that was poking out of the water.
Atop
in
the pole, perched Hke
some cartoon
gargoyle,
huge northern green. As we floated around it
circles, the frog remained "on post." Perhaps, in its
was
a
dim ampliibian
We
brain,
weren't about to
it
let
we couldn't
we could.
thought
on
that
see
it.
It wasn't long before I began to predict the frogs'
underwater routes by watching the wakes left by the
powerful thrusts of their hind legs. Their predators,
too, I mused, must look for similar clues. When a
bumper crop of frogs turned up one year in our garden pool, a mob of foraging black-crowned night
herons discovered them. Raucous cries from those
joyous opportunists tipped us off to the garden party.
They dined on every last fi'og, as if each one were an
irresistible,
Arthur Rackham, King Log, from Aesop's Fab/es, 1912
delectable hors d'oeuvre.
in the summer heat, and the
become more densely packed around it, a
similar fate may await these northern greens. A
more diverse gathering bobcats, coyotes, foxes,
raccoons may attend the next garden party. We'll
As the pond shrinks
frogs
scant thirty-one pounds, was relatively easy to haul
out to the pond and trundle across the gooey muck.
my
and best dog, hopped into the
bow and looked around smartly, eager to play the
double role of ballast and tracker. One push with
the kayak paddle and we slid over the flotsam of
reeds and into open water. My other two dogs took
oft~ to greet us at the other side of the pond. We
were seriously messing about.
Sukey,
64
smallest
NATURAL HISTORY
July/August 2005
—
—
probably miss that one, but we'll be back next
summer
to
do some more messing about.
Dru Clarke
tanght nmi-ine science and ecology in secondary
school for thirty-one years. She lives in Kansas. Clarke last
wrote for "Endpaper" in September 2003.
OPEN NOW
This groundbreaking multimedia -rich exhibit
examines the possibility of environmental
failure in Southern California by looking
at ancient civilizations and the lessons
contemporary societies must lear"
^^
in order to survive.
1
r
.:»5t»,«ff.^'
W^
.,^;i»^:^iS
7 T?!r,»r^
..j.
i|
pwp
ji,.<i
t^sAVSI
900 Exposition Boi
Los Angeles, California 90007
after dark on
For
more information
FIRST FRIDAYS
with dance, music, performance and discussion.
213-763-DINO
or visit
call
www.nhm.org
of Los Angeles County
Qy^NENBERG GA)m
Inspired by
Collapse:
The exhibition
is
made
How Societies Choose to Fail or Succeed,
by Jared Diamond, published by Viking Penguin.
possible by the Annenberg Foundation and supported in part by a generous grant from The Ralph
Promotional support by KCET, Public Television for Southern and Central California, and 89.3
KPCC Southern
l\J.
Parsons Foundation.
California Public Radio.
©2005 Jared
Diamond.
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