Do Crocodiles Cry? The Truth Behind Crocodile Tears

Why do crocodiles produce tears?

Like most land vertebrates, crocodiles have glands that make tear fluid. In crocodilians a large gland behind the eye, called the Harderian gland, together with smaller tear glands, produces fluid that lubricates the eye. The fluid washes away dirt, keeps the surface of the eye from drying and helps the eyelids and the third eyelid slide smoothly.

That third eyelid, the nictitating membrane, is a clear sheet that sweeps across the eye from the front corner. It protects the eye underwater, much like swimming goggles, while still letting the crocodile see. When a saltwater crocodile or another crocodilian has been basking on land for some time, its eyes can start to dry out, and visible tears are most likely then.

Do crocodiles really cry while eating?

Surprisingly, yes, at least some of the time. In 2006 the American neurologist D. Malcolm Shaner and University of Florida zoologist Kent Vliet decided to test the old story. Because crocodiles usually feed in the water, where tears cannot be seen, Vliet filmed caimans and alligators feeding on land at the St. Augustine Alligator Farm Zoological Park in Florida.

Five of the seven animals observed teared up while eating. The researchers published their results in the journal BioScience in 2007. They suggested that the hissing and huffing that crocodilians make while feeding forces air through the sinuses, which may stimulate the tear glands to empty fluid into the eyes. The tears are therefore a physical reflex, not a sign of sorrow.

How crocodile eyes are built for two worlds

A crocodile’s eyes sit high on the top of the head, so it can watch the bank while almost its whole body stays hidden underwater. Each eye has upper and lower eyelids plus the see-through third eyelid, and the eyes can be pulled down into their sockets for protection, for example during a fight or while seizing prey.

Crocodilians are mainly night hunters. Their pupils close to narrow vertical slits in bright light and open wide in the dark, and a reflective layer behind the retina, the tapetum lucidum, makes the most of dim light. It is this layer that makes crocodile eyes shine red or orange in a flashlight beam at night. Keeping such sensitive eyes clean and moist, in muddy water and in the drying sun, is the everyday job of their tears.

Are crocodile tears linked to emotion?

No evidence suggests that any reptile weeps from emotion. As far as scientists know, emotional crying, tears produced by sadness or joy, is a uniquely human behavior. Reptiles do have stress responses, and crocodiles show a surprising range of behaviors, from complex vocal communication to careful parental care, but their tears serve the eyes, not the feelings.

Do crocodiles cry to get rid of salt?

This is a common mix-up. Sea turtles and some seabirds get rid of excess salt through glands near the eyes or nostrils, so a sea turtle on a beach can look as if it is crying salty tears. Crocodiles that live in salt water solve the same problem with salt glands on the tongue instead. Their tears are not a significant way of removing salt. Learn more in can crocodiles live in salt water?

Where does the phrase “crocodile tears” come from?

The expression comes from an ancient legend that crocodiles weep for the victims they are eating, or weep to lure people close. A collection of sayings attributed to the Greek writer Plutarch suggests the idea was already familiar in antiquity, and the ninth-century Byzantine scholar Photios used the story as an example of false repentance. Medieval bestiaries, the illustrated books of animals popular in Europe, repeated it.

The tale spread widely in English through The Travels of Sir John Mandeville, a 14th-century book that described crocodiles that “eat them weeping.” Shakespeare used the image in several plays, including Othello, and the poet Edmund Spenser included a weeping crocodile in The Faerie Queene. Today the phrase “crocodile tears” means a fake show of sorrow, and similar idioms exist in many European languages.

Crocodile tears in medicine

The legend even reached medicine. In 1926 the Russian neurologist F. A. Bogorad described patients who shed tears from one eye while eating, a rare condition that can follow recovery from facial nerve paralysis. He called it the “syndrome of crocodile tears,” and it is still known as Bogorad’s syndrome or crocodile tears syndrome.

Do alligators and caimans cry too?

Yes. All crocodilians, including the American alligator, caimans, crocodiles and the gharial, produce tears to protect their eyes. In fact, the animals that confirmed the “crying while eating” story were caimans and alligators, not crocodiles. For more on how these relatives differ, see alligator vs crocodile.

So the old legend is half right: crocodilians really do shed tears while eating, but the tears have nothing to do with guilt.