Crocs Cry Real Tears

There's an old myth that crocodiles cry in fake remorse while devouring a meal, which is why we say someone is "crying crocodile tears" when they insincerely turn on the waterworks.

But it turns out that crocs really do weep when they are eating, but surely not because they are feeling emotional.

Normally, it's rather tricky to work out whether crocodiles are crying when they eat because they spend so much of their time in water and are such feisty creatures they are difficult to train to eat on land.  So instead of looking at crocodiles, scientists from the University of Florida decided to try and work out once and for all whether these scaly reptiles do indeed cry while eating, by watching four caimans and three alligators - the slightly less formidable close relatives of crocodiles - which were trained to feed on dry land at a zoo in Florida.  

And the researchers saw that the most of the caiman and alligators did cry while tucking into a meal, some of them even bubbled and frothed from their eyes, confirming what until now had just been anecdotal reports of weeping diners.

There are a couple of possible explanations for the tears shed by the caimans and alligators while they were eating; it could be linked to the hissing and huffing behaviour that often accompanies feeding - by forcing air through their sinuses crocs might stimulate the production of fluid in the lacrimal glands or tear glands; it's also possible that the mechanical action of biting down on their food might cause the jaw muscles to squeeze tears out of the tear glands.

And like human tears, croc tears are likely to be a way of protecting the eyes.  While the crocs are feeding there is a lot of activity around the head, when they are subduing their prey, and tears as well as pulling their eyes deeper into their sockets, might help protect them from getting damaged.

And a rather interesting thing is that the idea for this study came partly from a condition in humans known as crocodile tears, in which people cry when they eat.  The scientists wanted to get to the bottom of whether crocodiles really do shed tears, and it seems they do.