Animal tears
PHOTO: N. SRIDHARAN
Are animals known to shed tears?
SAHANA RAYAN
Hyderabad
Many animals shed tears. Even crocodiles, alligators and caimans do. But this occurs while they are eating. However, this phenomenon is not an emotional response but the function of the tears is to lubricate the eye.
This may be even more relevant for crocodiles because
they have a third eyelid, also known as a nictitating membrane.
The weeping may be a byproduct of a feeding
behavior: the hisses and huffs that crocs make while eating.
These acts may force air though the reptiles' sinuses,
where they stimulate fluid in the tear, or lacrimal, glands
and force them into the eyes-sometimes to the point of
overflow. Even simpler explanations could also account
for crocodiles' tears.
The general contraction of jaw muscles during the bite
reflex may help to squeeze tears out of the lacrimal glands
and ducts.
Another explanation is that accumulated tears that well
up below the eye are simply displaced and run down the
jaws when the crocodile moves its head to eat, and it's easy
to associate that 'crying' with eating. In the violent world
of crocodiles, tears likely play a protective role.
There is a lot of drama going on around the head while
they are subduing prey. A crocodile's eyes also recede into
its head as the animal manipulates its mouth.
They may just be trying to protect the eye. Crocodile
tears are difficult to observe as the animals spend so much
time in the water.
The University of Florida's Kent Vliet revealed the behaviour
with controlled feedings of captive alligators and
caimans - two animals closely related to crocodiles - that
had become conditioned to eating on dry land.
The animals were fed a diet of dry, dog-treat-like biscuits,
and they shed tears during most meals. Some of the
reptiles even produced more dramatic foaming around
their eyes. "At times you can see big bubbles coming up in
the corner of the eye, sort of like soap bubbles," Vliet said.
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