Do snakes sleep with their eyes open?

People have been spreading the rumor that snakes sleep with their eyes open for years - so which one is it, a myth or a fact?

Busted! This one’s a myth. If you’ve ever seen a snake in the wild coiled up and not moving, you are never sure whether or not he is sleeping, because his eyes appear to be open.

Snakes do not have legs, which means that they need to slither in order to get around, requiring them to be very close to the ground. The snake may come upon sharp grass, dirt, and debris, which can all affect his eye. In order to protect them, evolution has given snakes clear, transparent eyelids called brille.

Even when the snake closes its eyes, it can still see through these “glass” eyelids. This type of eyelid is made out of skin and sheds along with the rest of the snake. When the old skin grows old and tough, the snake begins to grow a new set of eyelids underneath the old one.

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