Dolphins are truly amazing creatures, scientists have repeatedly puzzled over their way of life. But the question of how dolphins sleep has long puzzled researchers.

Dolphins are mammals that breathe oxygen but live in water. Their skin is very delicate to be on the surface without water for a long time. So dolphins can’t sleep when swimming near the surface of the water. But they can’t sleep under water either, they need to rise to the surface to swallow air .. So how do they sleep then?

For some time it was believed that dolphins did not need a dream at all, although it seemed absurd - every living creature needed rest. Then the theory appeared that they sleep with open eyes, but it was not confirmed either. Scientists then suggested that dolphins might sleep in fits and starts between gulps of oxygen, but this theory turned out to be wrong, although it’s closer to the answer.

And only recent studies have confirmed that dolphins, like all mammals, still sleep. But their rest is not quite ordinary. Indeed, for a full sleep it is necessary to remain in a state of immobility, that is, not to control your body. But for mobile dolphins, such a rest is impossible, since they are forced to regularly rise to the surface for oxygen.

How do dolphins sleep?

Nature arranged everything so that the dolphins rested, not freezing in stillness. How then do they sleep? Scientists were able to find the answer to this question by studying the brain of dolphins using biocurrents. And then the mystery cleared up. We all know that during sleep, both in humans and animals, both hemispheres are “turned off”.But not dolphins. As it turned out, the dolphins of the left and right hemispheres sleep in turn, and while one is resting, the other is awake. After an hour and a half they replace each other: the hemisphere, which was resting, becomes active, and which was awake, falls asleep. This is how the dolphin sleeps, and when it wakes up, both hemispheres are already active. It also became clear why dolphins sometimes have one eye closed - they just see sweet dreams.

How do dolphins breathe while sleeping?

When it’s time for the dolphin to rest, he “turns off” the right hemisphere of the brain and closes the left eye, and the left hemisphere is “on duty” at this time. It, as it were, controls the body of the animal, making sure that it rises to the surface in time for oxygen. An hour and a half later, a “change of the guard” takes place: the dolphin “turns off” the left hemisphere, closes the right eye, and now the right hemisphere is awake, controlling breathing.

Here is such a "half" dream. But it is he who allows the animal to receive the necessary oxygen during sleep, control the body and even lead an active lifestyle. For example, to hunt for small fish.

Therefore, it is often difficult to immediately determine whether a dolphin is sleeping or awake. During sleep, these mammals are at shallow depths, from time to time they hit the tail with water, rise to the surface, inhale the air and slowly fall back under the water.

Interesting fact: newborn dolphin cubs in the first month of their life do not sleep at all. The hemispheres of the brain are still underdeveloped, so they have to rise to the surface for oxygen every 30 seconds. And only after a month do they gradually get used to the adult sleep regimen.