Dolphins are able to sleep without drowning because they have gills, like fish do. have a special opening that allows air in but not water. sleep on just one side of their brain at a time. inflate their bodies before sleep, which maintains them floating upright so they can breathe without taking in any water.

They sleep on just one side of their brain at a time

Explanation:

Dolphins are different from fishes that can breathe underwater.

It is necessary for them to get to the surface of the water at intervals to breathe air.

While sleeping, dolphins allows one hemisphere of their brains fall asleep while the other half is fully conscious. This means that If the left brain is sleeping, the right eye stays open and if the right brain is sleeping, the left eye stays open.

This happens so they always know when it's time to surface and breathe and when to escape when there is trouble.

sleep on just one side of their brain at a time

Explanation: While sleeping, the dolphin shuts down only half of its brain together with the opposite eye while the other half of the brain stays awake at a minimum level of alertness. It uses its attentive side to watch for predators or obstacles. The dolphin also reverses this process to rest the active side of the brain and awake the rested half.