Explanation: When a crocodile devours a human animal, its eyes secrete salt and shed tears. It is a metaphor for the false charity of the wicked. False goodness is really badness!

Biologists have found that the crocodile's "tears" are salt-containing fluids excreted by the crocodile when it devours its prey, and that it does this in order to drain the body of excess salt. There is a salt gland near the eye of the crocodile, which is a kind of "salt water desalinator", the role is to help the crocodile will be excess salt out of the body.

Expanded:

The crocodile's tears are a famous Western proverb, and legend has it that crocodiles shed false tears before eating people. In fact, crocodiles are not sad at all, but are lubricating their eyes. When the crocodile dives into the water, the transient membrane in the crocodile's eyes closes, both to see underwater and to protect the eyes; when the crocodile is on land, the transient membrane is used to moisturize the eyes, which needs to be lubricated with tears.

Ancient Western legend has it that the crocodile is both fierce and cruel, and cunning and treacherous. When it spied on people, animals, animals and fish and other prey objects, often the first tears, as a compassionate, so that you are paralyzed by the illusion of its sudden attack on the loss of vigilance in the unguarded state of its ferocious devouring.

Another story has it that after the crocodile catches its prey, it will shed tears of sympathy while devouring it greedily. In any case, this phrase is a metaphor for false tears and disguised sympathy. And then the convention was extended to specialize in satirizing those who hurt others on the one hand, and pretending to be compassionate and kind on the other hand, the insidious and cunning people.