Question

Which animal sleep with open eyes ?

Answer 1

Common ones with which you probably already have experience would be all fish, all snakes, insects, crustaceans (crabs, shrimp/prawns) and so on. In fact, the majority of animals on earth lack eyelids, so most animals sleep with their eyes open.

Answer 2

I know that dolphins sleep with 1 eye open and some fishes and snakes too sleep with their eyes open..