Some sharks such as the nurse shark have spiracles that force water across their gills allowing for stationary rest. Sharks do not sleep like humans do, but instead have active and restful periods.

How do sharks sleep if they can't stop swimming?

Sharks do not experience sleep the same way humans do. … Sharks that can stop swimming in order to rest use specialized apparatus known as spiracles to force oxygen-rich water through their gill system. Rays and skates, which are close relatives of sharks, also use spiracles to breathe.

Do sharks sleep with their eyes open?

Whatever method they use to breathe, sharks are able to engage in periods of deep rest while still but do not fall asleep in the traditional sense. Lacking eyelids, their eyes remain perpetually open, and their pupils still monitor the motion of creatures swimming around them.