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YOUNG SCIENTIST SECTION
BY THOMAS DANNY J
LAYOUT: ERIC LUA
“There are claims
about animals
displaying erratic
behaviour and
moving to higher
ground in the face
of impending
danger.”
Do you reckon that animals have a sixth sense? Well some zoologists
certainly seem to think so. They believe that certain animal species
have an innate ability to sense subsonic waves from an earthquake
or tsunami.
There are claims about animals displaying erratic behaviour and
moving to higher ground in the face of impending danger. For
instance in Sri Lanka, up to an hour before the tsunami bore down
on the coast land (following the infamous December 2004 Sumatra
quake) elephants ‘trumpeted hysterically’ and ran for higher
ground, flamingos abandoned their low-lying breeding areas, and
dogs refused to go outdoors.
But by the same token, many other animals in the same area were
caught by surprise and drowned when the tsunami hit. In such
scenarios, sometimes animals display abnormal behaviour;
sometimes they don’t. That is why the evidence in support for
animals having a sixth sense is debatable and not widely accepted.
However, it is possible that some animals may have heard the
quake before the tsunami made landfall. Underwater quakes can
generate sound waves known as infrasound, which are below 20
Hertz—beyond the limits of human hearing (which is ranges from
20 Hertz to 20,000 Hertz) but within the hearing range of many
animals like dogs, elephants, tigers and pigeons.
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Besides their hearing abilities,
another remarkable way that
animals can sense that
something is amiss when a
quake has struck is through
detecting ground vibration. A
number of them are quite adept
at detecting vibrations that are
imperceptible to humans.
Rayleigh waves (vibrations from
earthquakes) can move through
the ground at 10 times the
speed of sound. These vibrations
can reach coastal areas hours
before the Tsunami hits. The
low frequency Rayleigh waves
can be detected on the ground
and through the air by
mammals, birds, spiders and
insects.
To get a closer look at how they
sense vibrations, and for what
purposes they create their own
vibrations, here’s a snapshot of
a few critters that are naturally
endowed with ‘state-of-theart’ seismic communication
systems!
Jumping Spiders (Salticidae)
Jumping Spiders are right up
there among the world’s most
fascinating arachnids. And do
they know how to razzle dazzle
us with their colourful mating
displays! Male spiders approach
the females and start to oscillate
their abdomens and rap-a-taptap and fling their legs in an
almost flamenco-like
manoeuvre!
The low frequency drumming
vibrations are detected by
females using exoskeletal
sensory structures (through their
legs in this case). However, one
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other kangaroo rats. Apparently,
the footroll or series of thumps
is done both on top of and
inside their burrows.
By keeping their tap dances
near-constant, the rats can
easily distinguish between
neighbours and foreign
intruders. Their fleet footwork
is also used to signal their
awareness of predators like
snakes as well as to compete for
mates!
Source: Lukas Jonaitis
Namib Desert Golden Mole
Jumping Spider
Kangaroo Rats
(Eremitalpa granti namibensis)
The Namib Desert golden mole
is an extremely cute looking,
blind critter. This little furball
searches at night for tasty
termites that live near grassy
mounds called ‘tussocks’. When
desert winds blow through the
grass, they set the tussocks into
resonance.
(genus Dipodomys)
These critters are likely the
fastest tap dancers on the
planet. While they hop about
on two legs, they also drum out
some incredibly fast ‘footrolls’
in the dirt to communicate with
The ravenous golden mole uses
these vibrations to guide its
termite tracking. As it nears the
tussock, it is able to detect the
subtle vibrations of the termites
themselves. It senses these
shouldn’t underestimate the
cannibalistic voracity of female
spiders. If the dance is not well
received by the female, they will
reject the males as a mate and
will likely eat them! (Crikey!)
Source: National Park Service
Kangaroo Rat
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Source: G. Rathbun
Namib Desert Golden Mole
vibrations through its malleus
(middle ear bone) which moves
in response to seismic signals.
G o l d e n m o l e s c a n h ea r
vibrations under the sand as
long as their ears are buried
and in contact with the sand.
They use a cute “head-dipping”
technique to achieve this by
burying their heads every few
s te p s t o s tay o n c o u rs e .
Puerto Rican White-lipped
Frog (Leptodactylus albilabris)
This critter sprang to attention
because of its super sensitivity
to vibrations from a distance.
Peter Narins and neurobiologist
Edwin Lewis, who teamed up to
decode its seismic marvel,
determined that its sensitivity
arises from an inner ear sac
brimming with calcium
carbonate crystals.
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v i b ra ti o n s o f i t s o wn — by
producing a seismic thump
when their vocal pouch expands
and makes contact with the
ground. Males in the
surrounding area sense these
thumps and respond in kind,
to distance themselves from
other males as well as to attract
females.
or lift up a foot (although it is
not clear how this helps their
cause). Ground sound vibrates
the toe bone and travels up
through the leg, before jangling
the middle ear. Other times,
t h ey m ay l ea n fo r wa rd
dramatically and put their trunk
on the ground to the same
effect.
Elephants (Elephantidae)
Well that about sums up my
snapshot of critters! To say
‘animals are psychic or intuitive’
might be overplaying it, but we
can certainly agree that they
have heightened, refined senses
that easily top humans’ sensory
abilities. In fact, we’re probably
‘vibrationally challenged’ in
comparison!
It just wouldn’t be right to leave
a mammal of this size out of
the whole seismic shebang. So
here we have it! For years, we
have known that their trumpet
calls contain low rumbling
frequencies. But did you know
that elephant vocalisations also
shake the ground? Also, they
are able to detect vibrations
through their nose and their
toes, honing in on the shaking
source using their unique
sensory structures.
To listen to such vibrations, they
will sometimes deftly place the
tips of their toes on the ground,
As for natural disasters, if
nothing else, perhaps we are
better off watching animals for
cues since they are always
vigilant. It is after all what
helps to keep them alive in the
wild.
Even subtle vibrations shake the
crystals, which in turn excite
ce l l s t ha t p ro d u ce n e r ve
impulses. The frog also produces
Source: Stu Seeger
Source: United States Geological Survey
Puerto Rican White-lipped Frog
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Elephants