Odatria
The electronic newsletter of the Victorian Herpetological Society.
Issue 20, December 2016
Limbless
Locomotion:
Sliding, sidewinding,
saltation and more....
Recovering the
Striped legless
Lizard
Top 10 Weirdest,
Wackiest Lizards.
Cover shot: Has noted wildlife photographer and writer Michael Cermak been employing genetic engineering
in tandem with evoking medieval incantations? Perhaps he has just acquired a new version of Photoshop....
Cover: Thorny Devil ((Moloch
Moloch horridus
horridus))
by Adam Sapiano.
See you at the:
2017 VHS Reptile & Amphibian Expo.
Melbourne Showgrounds
Saturday 4th March 2017, 9am to 4pm.
Special guest speakers:
Prof. Bryan Fry & Joe Ball.
Free entry for VHS members!
Issue 20, December 2016
The Wrangler Writes.
T
he VHS committee
would like to be on
public record that it is
not in any way associated with a certain
licensed snake removalist in the western
suburbs who is recently
rumoured to have taken
to wearing a red suit
with white fur trim and
insists on attempting to
climb down chimneys
with the aid of a large
snake hook.
We have received some
great positive feedback
on the new meeting
venue, with a number
of members commenting on the great facilities at the Anglers’
Tavern, and the convenient location. Although I
was unable to attend
the last meeting due to
family illness, one
member went out of his
way to tell me that he
thought Rex Neindorf’s
presentation was one of
the best he had ever
seen; thanks Rex! We
continue to source the
best possible speakers
from around the country, so make sure you
get along to meetings
whenever you can.
And whilst on the subject, we have secured
the services of venom
expert Prof. Bryan Fry
and blue-tongue boffin
Joe Ball for our expo in
March 2017. Both will
also be speaking at a
special BBQ at the Anglers’ Tavern on the Friday night, so make sure
you watch our website
and Facebook page for
further details. It will be
an event not to miss!
This issue of Odatria
features a fantastic article on snake locomotion by Kit Prendergast—Kit, you’ve done
it again!
Don’t forget to support
our sponsors,
Minibeasts and Karingal
Veterinary Hospital,
without which Odatria
would not be possible.
Lastly, have a happy
and safe Xmas and a
prosperous New Year.
John McGrath
2016 VHS Office
Bearers:
President: Adam Sapiano
Secretary: Kevin Welsh
Treasurer: Shane Brodie
Exec. Committee: John
McGrath, Shane Robinson
Odatria is published by the
Victorian Herpetological
Society Inc. copyright 2016
all rights reserved. Apart
from any fair dealing, as
permitted under the Copyright Act, no part may be
reproduced or stored by
any process without written
permission. Uncredited
photos are from the VHS
archives. Photos published
remain the property of both
the VHS and the respective
authors and are subject to
full copyright and all rights
are reserved. Views or
opinions expressed are
entirely those of the relevant authors and should
not necessarily be taken to
represent the VHS.
Correspondence:
[email protected]
or the editor:
[email protected]
‘What you lookin’ at?’
Page 3
Odatria
Limbless Locomotion.
Sliding, sidewinding, saltation and more: how serpents
have adapted to life without legs.
Zoologist and
conservationbiologist
Kit Prendergast
tackles the
science of
slithering....
T
here are approximately 3,400 extant
species of snakes, having a
cosmopolitan distribution
and occupying a huge
range of habitats. The evolutionary success of this
group is due in part to their
incredible locomotory
abilities. An obvious diagnostic feature of snakes is
their state of ‘leglessness’:
the earliest snakes possessed tiny hind limbs,
however through the course
of evolution these were
lost. Early-diverging
snakes (e.g. boas and pythons) still retain vestiges
of the pelvic girdle and
hind limbs, however these
are functionless. Natural
selection was responsible
for the loss of limbs, so
snakes’ body plan must
confer adaptive benefits.
Nevertheless, being legless
poses significant chal-
Page 4
lenges in terms of locomotion.
Stem snakes (the earliest
snakes identified from the
fossil record) evolved approximately 125 million
years ago, and crown
snakes (modern snakes)
evolved about 105 million
years ago. Both originated
on land (rather than in
aquatic settings), and
snakes’ distinctive long,
limbless body plan appears
to have evolved as an adaptation for burrowing. This
hypothesis is supported by
the analysis of fossils
(Dinilysia patagonica)
linked to ancestral snakes;
these possess a unique inner ear structure shared by
extant burrowing snakes
and lizards, but which is
absent in snakes living in
water or above ground.
Furthermore, all extant
snakes have an elongate
body with a relatively short
tail - a trait they share with
burrowing lizards.
Like ancestral fish and then
the first land-based
tetrapods, ancestral reptiles
inherited a form of locomotion based on alternating
lateral undulations of the
body. Most snakes retain
this pattern, however the
lack of legs and highly
undulatory nature of movement places very high
twisting forces on their
vertebral columns. To
cope, snakes have two
additional sets of zygapophyses - paired bony
processes that interlock
each vertebra with the vertebrae above and below.
These help limit torsion,
without dramatically restricting the lateral bending
of the vertebral column.
Issue 20, December 2016
But moving on land using
lateral undulations is much
harder than in water.
Tetrapods use their limbs
to generate thrust. The
solid framework of bones
and muscles functions as a
system of levers, transmitting force to the substrate
and powering the animals
along. Without limbs,
snakes lack these propulsive forces. Instead, their
anatomical basis for movement involves their long
backbones (comprising
several hundred vertebrae)
and complex, multisegmented muscle chains
and tendons. On surfaces
with some texture, snakes’
scales create passive friction, with less directed
towards the front than the
back, enabling forwards
movement. The amount of
friction can be actively
adjusted by modifying the
angle between the scales
and the substrate – too
much would impede movement.
ment – is the most widespread mode of locomotion. Concertina locomotion and sidewinding are
also common, and are used
when there are insufficient
substrate projections necessary for lateral undulations.
All generate propulsive
forces through laterally
flexing the vertebral column by contracting axial
muscles.
During lateral undulations,
horizontal waves travel
down alternate sides of the
body. Although limbed
reptiles also often move
with lateral
undulations,
snakes differ
because, lacking
limbs to provide
fixed points for
generating propulsive force, they instead
rely on moving their body
continuously to push past
fixed irregularities (e.g.
stones, grass tussocks,
bumps) in the environment.
Despite each point generating a sideways force, the
lateral forces on opposite
sides of the body cancel
out, leaving a net rearward
force which propels the
snake forwards. Studies
have revealed that laterallyundulating snakes move by
continuous posterior propagation of alternating unilateral muscle activity, with
limited contribution from
the tail. Whilst this form of
locomotion works well on
rugged substrates, it gets a
snake nowhere on a smooth
surface!
‘SIX modes of SNAKE
LOCOMOTION are recognised.’
Sidewinding is effective on
low-friction, shifting substrates like sand or mud.
Watching a snake sidewinding is quite bewildering! Despite the impression
The mechanics of
movement.
Six modes of snake locomotion are recognised:
lateral undulation, sidewinding, concertina, rectilinear, ‘slide-pushing’ and
saltation. Several different
modes may be employed
simultaneously at different
points along the snake’s
body. Species differ in their
tendency to use a particular
mode, and this is associated
with differences in body
plan and adaptations to the
substrate they frequently
encounter. Lateral undulation – characteristically
called serpentine move-
Pythons and pythons still retain vestiges of the pelvic girdle and hind limbs.
All images by Kit Prendergast.
Page 5
Odatria
Limbless Locomotion (cont).
that the creature is throwing loops of its body in all
directions, sidewinding
actually involves a highlycomplex locomotory pattern in which sections of
the body are alternatively
lifted, moved forward and
then set down. During any
sequence, the body is in
static contact with the
ground at two points. Sidewinding can occur in a left
or right-handed manner and
leaves a characteristic
series of separate, parallel,
J-shaped tracks, each orientated at an angle to the direction of travel. The tracks
are about as long as the
snake’s body.
Sidewinding is exemplified
by the snake whose common name alludes to its
preferred method of locomotion: the Sidewinder
(Crotalus cerastes). By
varying the proportion of
its body that is in contact
Page 6
with the sand, this small,
venomous pit viper can
ascend steep, sandy dunes
without slipping – a feat
that related pit vipers cannot accomplish. Other desert snakes that often use
sidewinding include Asian
and African vipers, Horned
Adders (Bitis caudalis) and
Peringuey's Adder (Bitis
peringueyi). Specialised
sidewinders travel with
considerable speed, attaining forward velocities of
2.0 total lengths per second. Increased velocity can
be achieved by using sidewinding on sand, and sidewinders have been shown
to switch from pure lateral
undulations, to lateral undulations with sidewinding,
to pure sidewinding, with
incremental increases in
speed.
But sidewinding is not confined to desert-dwelling
snakes, and is also utilised
effectively by other species
to traverse slippery substrates, such as slick, slimy
mudflats (e.g. the Dogfaced Water Snake, Cerberus rynchops). In fact,
sidewinding can be induced
in many snakes, although
they are often reluctant to
do so. Not only is sidewinding adaptive for travelling on yielding or slippery surfaces, but by preventing slippage at points
of contact, it confers energetic advantages relative to
all other forms of snake
locomotion.
Concertina locomotion
involves the anterior region
of the body remaining stationary while the posterior
end is drawn up behind it
in a series of tight curves.
The posterior end then
provides a region of static
contact, enabling the anterior region to be extended
forwards. The process is
then repeated. Concertina
locomotion is used on surfaces that are unsuitable for
lateral undulations, but
where enough static
friction exists to prevent
backwards slippage. This
form of locomotion is most
commonly used when
crawling through burrows
or tubes - lateral undulations are restricted, yet
snakes can brace their bodies against the walls.
Concertina locomotion is
not for animals in a hurry.
Banded Water Snakes
(Nerodia fasciata) travel
only 0.05 total lengths per
second using this form of
locomotion, but can
achieve 1.88 total lengths
per second using lateral
Issue 20, December 2016
undulations. It also requires
a lot of energy; Eastern
Racers (Coluber constrictor) use seven times more
energy when employing
concertina locomotion,
compared with lateral undulation.
Rectilinear locomotion
differs from other forms of
snake locomotion in that it
does not rely on alternating
contractions of the lateral
muscles along the trunk.
Rather, both of the lateral
muscle masses act in
synchrony, sequentially
contracting and relaxing,
which draws the body
forward in a fairly straight
line. Rectilinear locomotion mainly involves two
series of muscles which run
from the ribs to the skin of
the ventral surface. The
costocutaneous superior
muscles pull the skin forwards relative to the ribs;
the ventral scales then
anchor the body to the substrate. Next, the costocutaneous inferior muscles pull
the ribs - along with the
vertebral column, axial
muscles, and viscera forward relative to the
stationary ventral skin.
Several waves of these
symmetrical contractions
pass down the body at any
one time, so that a number
of points of stationary
contact are established.
This creates a bizarre effect
in which it appears that the
ventrolateral skin is crawling on its own, whilst the
dorsal skin moves at a
nearly even rate! Rectilinear locomotion is most
common in large snakes
like boids and vipers,
however all snakes are
likely capable of using this
mode of locomotion.
Snakes sometimes
use ‘slide-pushing’
when travelling on
low-friction substrates. Although
similar to lateral
undulation in that it
also involves alternating waves of
body motion, in
slide-pushing there
are no fixed points
in the physical
environment to
generate forces
pushing the body
forwards. Instead,
the snake moves its
body incredibly quickly,
propagating waves so
rapidly that enough sliding
friction is generated to
propel it forwards. This
form of locomotion isn’t
very efficient – despite all
that wriggling, slidepushing snakes appear to
be simply flailing about,
and only progress
gradually.
Finally, saltation is a rare,
pretty extreme form of
locomotion employed by
the Horned Adder, a short,
heavy-bodied viper from
southern Africa. The snake
rapidly straightens its body
from anterior to posterior,
which actually causes it to
be lifted entirely off the
substrate. Only very small
individuals move in this
manner.
Unlimited by a legless lifestyle.
Climbing steep surfaces
poses challenges for any
animal: the entire body
weight must be continually
lifted, in addition to
preventing slipping (and
potentially fatal consequences). Despite lacking
grasping limbs, claws or
Although most common in large species such
as boids and vipers, all snakes are likely capable of rectilinear locomotion.
the adhesive toe pads
present in other arboreal
animals, snakes from
diverse lineages have independently evolved to be
remarkable climbers.
Snakes use muscular gripping forces to climb, as do
primates, but have a
distinct advantage because
their entire body can be
used (rather than just the
hands, feet and sometimes
the tail), enabling them to
grip branches spanning a
wide range of diameters.
If snakes are climbing
rough, relatively horizontal
surfaces, with adequatelyspaced irregularities, they
can shimmy up without
needing to use their body
for additional grip. But
when climbing smooth,
steep, cylindrical structures, snakes use a type of
concertina locomotion
involving periodic static
gripping: looping the body
around a branch one to
three times, stretching
forwards, then looping
around again and dragging
the lower part of the body
up behind. This ‘frictiongripping’ concertina locomotion prevents slipping,
but requires the application
‘In this EXTREME
Page 7
form of locomotion,
the snake’s body is
lifted ENTIRELY
OFF THE
SUBSTRATE.’
Odatria
Limbless Locomotion (cont).
of considerable force, and
involves a lot of stopstarting. Energy expenditure is high, and progress is
relatively slow.
Given the energetic cost of
using muscular forces to
grip inclined, cylindrical
surfaces, and that snakes
have considerable control
over the size and orientation of their grip, one
would expect some economisation in that a minimum
amount of exertion would
be used. Yet a study in
2014 found that this was
not the case; rather, snakes
have a policy of ‘safety
first’ and will grip the
substrate with a safety
factor often exceeding
three. Of the five species
examined, Boa Constrictors, the species least specialised for an arboreal
existence, were the most
safety conscious, with
safety factors of five
recorded. Nevertheless, the
extra force may represent
an overall energy saving,
because it minimises the
risk of slipping backwards,
which may be energetically
costly given that any
Arboreal snakes possess
specialised belly scales
that form a ventrolateral
keel.
Page 8
ground lost
must be recovered.
‘In Guam, BROWN
TREE SNAKES have
The ‘vine
snakes’, a
group of
become a nuisance, climbing
superb tree
power poles and causing
climbers comprising numerous colubrid
lineages, climb
using gapbridging, and
can cantilever
up to half their
body into open
space until
their head
reaches another
branch. Adaptations for gapand
bridging include slender,
laterallycompressed
bodies and large vertebral
lateral keel along with the
scales that prevent the body overlapping belly scales are
from bending dorsovenhighly effective at grasping
trally. Typically, specialist
irregularities. These snakes
tree-climbing snakes have
are therefore able to scale
slender bodies and relasteep gradients despite
tively long, prehensile tails
lacking supporting strucfor coiling around branches tures other climbing aniand providing anchorage as mals possess. The ventrothey extend their bodies
lateral keel is present but
forwards during concertina
less developed in snakes
locomotion. Arboreal
that occasionally climb
snakes also have belly
(e.g. Corn Snakes), but is
scales which span the
lacking in ground-dwelling
entire width of the body.
snakes, which are round in
On each side there is a
cross section and must exnotch, creating a fold
pend considerably greater
where the belly scales meet
energy climbing, as they
the smaller dorsal scales,
maintain a tight grip whilst
and forming a ventrolateral
slowly inching their way
keel. This allows such
upward.
snakes to modify their
tubular shape so that in
Brown Tree Snakes (Boiga
cross section they are flat
irregularis) are elite climbacross the bottom, and
ers. The exceptional climbcurved above. The ventroing ability of this intro-
ELECTRICAL
OUTAGES
SHORT CIRCUITS!’
Issue 20, December 2016
duced species has enabled
it to wreak havoc on Guam,
decimating the native
birdlife by climbing into
nests and eating birds and
their offspring. The snakes
are also causing a nuisance
by climbing power poles,
causing electrical outages
and short circuits!
Amazingly, snakes of the
genus Chrysopelea are also
capable of gliding between
trees. This is not a kamikaze free fall! Upon reaching the end of a branch, the
snake makes a J-shaped
bend and, after selecting a
destination, leans forwards
at the level of inclination
required to control its flight
path. It then thrusts itself
up and away from the
branch, and by spreading
the ribs and broadening the
body to create a deeply
concave ventral surface,
effectively creates a
‘pseudo-wing’ which
generates lift. Continual
serpentine movements are
made during ‘flight’, which
stabilises direction in midair and facilitates safe landing. Chrysopelea species
show remarkable control,
manoeuvring to avoid
obstacles when airborne,
and can glide for up to 100
metres! Gliding saves
energy, allows a greater
distance to be traversed in a
shorter amount of time, and
means the snakes do not
have to be exposed to
ground-based predators.
Some snakes have evolved
highly-modified bodies as
adaptations to an exclusively fossorial lifestyle, as
exemplified by the earlydiverging clade Scolecophidia, comprising
typhlopids (blindsnakes),
leptotyphlopids
(threadsnakes) and
anomalepidids (early
blindsnakes). To help burrow through the substrate,
these small snakes have
thin, cylindrical bodies,
blunted heads, highlyreduced eyes and short
tails. To reduce friction and
repel attacks from aggressive insects that abound
underground, they have
very thick, smooth,
overlapping scales.
The snake body plan can
also be considered to be pre
-adapted for an aquatic
lifestyle, given that snakes
have invaded fresh water
and marine environments
multiple times. Independent invasions of the ocean
occurred in the ancestors of
acrochordids, homalopsines, natricines, hydrophiids, and laticaudids.
As a result of their long,
thin physique, snakes
lation inherited from their
terrestrial ancestors formed
a good basis for this technique, however the biomechanics are very different.
Unlike the terrestrial application, where force is
applied at fixed points and
the waves travelling down
the body dampen towards
the rear, the regular waves
swimming snakes use
increase in amplitude posteriorly. And in terrestrial
lateral undulation, the propulsive force is generated
by lateral surfaces of the
body pushing against
irregularities in the substrate, whereas in swimming, snakes move forward
by their movement accelerating portions of the
surrounding water. As a
further adaption for swimming, aquatic snakes
evolved features for
increasing the surface area
against which their body
pushes against the water.
‘Sea snakes’ LUNGS have been modified to
increase buoyancy, and can OCCUPY
100% of the TRUNK.’
evolved a single (right),
elongated lung, providing a
natural buoyancy and flotation device. Sea snakes’
lungs have been further
modified to increase buoyancy and in hydrophiines
the lung extends to occupy
up to 100% of the trunk.
Snakes moving through
water employ a swimming
style resembling that of
long, thin fish, known as
anguilliform locomotion, in
which alternative waves
pass down the body, propelling the animal
forwards. The lateral undu-
Sea snakes (hydrophiids
and laticaudids) have laterally-compressed, paddlelike tails which generate
considerable lift. Swimming snakes also are highly
streamlined, with reduced
ventral scutes and small,
narrow heads not demarcated from the body. It may
be that the already streamlined, buoyant bodies of
snakes explains why hydrophiines have adapted to an
exclusively marine lifestyle; despite lizards having
a higher diversity than
snakes (5,600 species
Page 9
Odatria
Limbless Locomotion (cont).
versus 3,400), there are no
completely marine lizards.
‘Juvenile snakes’
ability to
OPTIMISE their
locomotory abilities
according to habitat is
HIGHLY
ADAPTIVE.’
sion of increasing adaptation for a fully-aquatic
existence.
Various snakes move on
both land and water; for
The trade-off between
example, Australian Tiger
aquatic and terrestrial
Snakes (Notochis scutatus)
locomotion is illustrated by
often forage in water.
amphibious sea kraits
Depending on the habitat
(family Lauticaudidae),
baby snakes experience
which forage in the ocean,
early in life - from areas
but return to land to shed,
lacking any bodies of
digest prey, court, mate,
water, to permanently
and lay eggs. Laticauda
swampy habitats - they
colubrina spends up to half
exhibit different locomoits time on land, and must
tory abilities. Different
ascend steep-walled, rocky
constraints on optimal mor- cliffs. The selective presphology and physiology
sure to retain effective
create a trade-off between
terrestrial locomotion
locomoting with maximum
means that this species is
efficiency on land versus
heavier-bodied and
water, such that improved
stronger than more aquatic
swimming/diving abilities
sea kraits like L.
correspond with reduced
laticuadata. Scientific tests
terrestrial performance.
have confirmed the supeThe ability for juvenile
rior cliff-climbing abilities
snakes to optimize their
of L. colubrina, however,
locomotory abilities
according to the
The author indulging in
habitat they grow
some slithery science.
up in is highly
adaptive; it means
their bodies are
matched to the
environment they
will live in. This
plasticity may also
have pre-adapted
ancestors of today’s
marine snakes to an
exclusive aquatic
environment, since
enhanced aquatic
locomotion by offspring growing up
in watery habitats
with the associated
reduced ability to
locomote on land
would have
favoured spending
more time in water,
driving a progres-
Page 10
this species’ speed of terrestrial locomotion is
nevertheless reduced by
80%, respective to terrestrial elapids, due to adaptations for swimming.
Hydrophiids – the most
specialized sea snakes – are
virtually unable to crawl on
land.
Scientists are interested in
studying snakes’ locomotory abilities as inspiration
for designing search and
rescue robots that can scale
buildings and cover various
substrates without having
appendages that could get
caught. Snake’s cylindrical,
flexible bodies are perfect
for squeezing through tight
spaces, climbing up/
through pipes, and traversing all types of terrain.
Issue 20, December 2016
Who am I?
F
ingers on your buzzers for the chance of a pick from the board!
I look much like an agamid and was classified as such for more than 15
years, but in reality I am quite unique.
Like some lizards, I can shed my tail as a defence mechanism, which
will then regrow—but I’m not actually a lizard!
I reach sexual maturity at about 15 years; on average females only
breed once every four years, and my lifespan is estimated to be up
to 100 years.
I possess a rudimentary third eye on the top of my skull which may be
sensitive to light.
Native to New Zealand, my heart rate is a mere eight beats per minute.
The sole surviving member of the order Rynchocephalia, I have remained virtually unchanged for 200 million years. I am the....
(Answer in next issue. Last time: I am the Pygmy Blue-tongue.)
????
Herpetofunnies!
Q: What do you call a snake that builds things?
A: A boa constructor!
Q: How do you measure a snake?
A: In inches. They don't have any feet!
Q: What do you call a snake who works for the government?
A: A civil serpent!
source: http://www.jokes4us.com/animaljokes/snakejokes.html
Page 11
Odatria
Kevin Welsh’s Top 10!
Weirdest, Wackiest Lizards!
W
ith the assistance of Wonderlists, here are ten of the
coolest, weirdest lizards in the world – large and small.
10. Miniature Chameleons.
The leaf chameleons (Brookesia spp.) are
endemic to Madagascar, where they are
often found beautifully camouflaged
amongst leaf litter. The smallest species,
Brookesia micra, was discovered sometime between 2003 and 2007 on the small
islet of Nosy Hara. It attains an adult
length of just 29mm, which also makes it
one of the world’s smallest reptiles.
9. The Armadillo Girdled Lizard.
This strange-looking species is found in South Africa
and grows to an average snout to vent length of 7.59cm. Also known as the Golden Armadillo Lizard due to
its colouration, it lives in rock crevices and cracks, and
if threatened, will curl up into a ball, taking its tail in its
mouth; it is then protected by the thick, squarish scales
on its back and spines on its tail. Females are also unusual in that they may feed their young.
8. Frilled Lizard.
Thanks to the large, colourful ‘ruff’ of skin around its neck, the
iconic Frilled Lizard of northern Australia and southern New
Guinea is able to put on one of the most striking displays in the
reptile world. This consists of spreading the expansive orange
or red frill, gaping to reveal the bright yellow mouth, raising the
body, and sometimes also holding the tail above the body.
Frilled Lizards are capable of bipedal locomotion but spend
most of their time in the trees.
Page 12
Issue 20, December 2016
7. Fantastic Leaf-tailed Gecko.
Also called the Satanic Leaf-tailed Gecko, Uroplatus phantasticus has an uncanny resemblance to withered or dried leaves. It grows to a maximum length
of about 15cm and is also endemic to the island of Madagascar.
6. Two-headed Bobtail Lizard.
Whatever you want to call it, the shingleback, bobtail, pinecone lizard, or stumpy-tail certainly
qualifies as one of the weirdest of lizards. As if it isn’t difficult enough to tell which is the
‘pointy’ end, here is one with two heads!
5. Flying Geckos.
Flying geckos don’t exactly fly, they glide – up to 60m! A number of
Southeast Asian geckos are equipped with anatomical features such as
elaborate digital webbing and skin flaps, and flattened bodies and tails.
When airborne, with all membranes extended, these creatures give the
impression of wearing miniature wingsuits.
Page 13
Odatria
Top 10! (cont.).
4. Sailfin Water Lizard.
Endemic to the Philippines, these unique creatures may reach up to a metre in
length. They are typically found near rivers and even have flattened toes that
enable them to run across water. Males possess exaggerated dorsal crests and
exhibit hues of violet, red or blue.
3. Galapagos Land Iguana.
Charles Darwin called Galapagos Land Iguanas, ‘ugly animals, of a yellowish
orange beneath, and of a brownish-red colour above: from their low facial angle they have a singularly stupid appearance’. They grow to 1-1.5m, weigh
about 11kg and bask on volcanic rocks during the day, retiring to burrows at
night to conserve heat. Galapagos Land Iguanas are primarily herbivorous
and can live for up to 60 years. They have a symbiotic relationship with birds,
which remove external parasites
from the iguanas.
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Issue 20, December 2016
2. Marine Iguana.
Marine Iguanas are also natives of the Galapagos Archipelago; Darwin christened them ‘imps of
darkness’, and described them as ‘disgusting clumsy Lizards....as black as the porous rocks over
which they crawl’. Unique among modern lizards, they forage exclusively in the cold sea, scraping
algae off rocks with their flat jaws. Marine Iguanas can grow to a snout to vent length of 34cm and
weigh up to 13kg. They possess a laterally flattened tail for propulsion and long, strong claws to
hold onto rocks in the currents. Their dark
colour enables them to rapidly absorb heat
after emerging from the water. Excess salt is
filtered by a nasal gland and excreted from
1. Komodo Dragon.
Inhabiting the Indonesian islands of Komodo, Rinca, Flores, Gili Motang and Padar, the Komodo Dragon is the largest living species of lizard, growing to over 3m and weighing up to
70kg. These giant varanids often prey upon deer but also hunt and ambush other mammals,
birds and invertebrates and consume considerable amounts of carrion. They have venomous
saliva that includes an anticoagulant and have been known to attack humans!
Page 15
Odatria
‘Monitoring
the past.’
In this offering
from 2002, Mike
Swan details
Melbourne
Zoo’s programme to assist the Striped
Legless Lizard.
Page 16
Issue 20, December 2016
If there are any particular articles that you would like to see reproduced,
or you have one that you would like to share, please contact the editor.
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