Scientists discovered that the "crocodile tears" turns out to be true! The idiom, meaning an insincere show of sadness or sympathy , is supposedly based on
alligator crocs weeping when they eat their victim.
Well, that turned out to be right on the money:
For centuries insincere humans have been said to cry crocodile tears—a nod to the famous tale that crocs weep with false remorse while devouring their prey.
Now research has shown that some reptiles really do shed tears during a meal, but most likely for biological rather than emotional reasons. [...]
"The general contraction of jaw muscles during the bite reflex may help to squeeze tears out of the lacrimal glands [and] ducts," croc expert Britton said.
"[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."