Bottlenose Dolphins Sleeping Whales : Marine mammals such as whales and dolphins spend their entire lives at sea.. Dolphins rest in a unihemispheric sleep, meaning they only rest half their brain at one time. Whale sleep patterns are different from land mammals in that they are never really unconscious when they sleep. Dolphins generally sleep at night but only for a couple hours at a time. Advertisement whales and dolphins are mammals, so in a lot of ways, they are just like human. Observations of bottlenose dolphins in aquariums and zoos, and of whales and dolphins in the wild, show two basic methods . Marine mammals such as whales and dolphins spend their entire lives at sea. Like whales, dolphins, and the related dall's porpoise, sleep with one . They either rest quietly in the water, vertically or horizontally or sleep while . So how can they sleep and not drown? These unique marine mammals show two basic methods of sleeping: When sleeping, dolphins often rest
