So how can they sleep and not drown? Observations of bottlenose dolphins in aquariums and zoos, and of whales and dolphins in the wild, show two basic methods of sleeping: they either rest quietly in the water, vertically or horizontally, or sleep while swimming slowly next to another animal.

How does a whale breathe while sleeping?

The answer is simple, YES they do. Their bodies shut down but only half of their mind stays at rest so that they conscientiously remember to breathe. Breathing near the surface where whales sleep allows them to breathe more conscientiously, meaning each and every breath counts.

How long do whales sleep for?

They cannot sleep for much longer than 30 minutes without risking lowering their body temperature due to inactivity. A very common assumption is that whales sleep with half of their brain 'shut off' and one eye closed.