Sleep is a natural and indispensable need for all mammals on the planet. However, the truth about dolphin sleep has long been a mystery to researchers. Do dolphins really sleep with one eye open? It was once believed that these animals rest "snaps" between breaths of air or even sleep deprived at all. Both of the latter assumptions turned out to be wrong. Today, scientists already know the true answer to the question of how dolphins sleep.
Interesting information about dolphins
Dolphins - warm-blooded mammals from the order of cetaceans - rightfully earned themselves the fame of one of the most mysterious creatures on Earth. The characteristic nickname of dolphins - "People of the Sea" - emphasizes the fact that their intellectual potential is so great that they are considered smarter and smarter than all other animals on the planet.
Dolphins live in packs. Among these creatures developedmutual assistance to each other, sometimes reaching self-sacrifice. Dolphins are able to communicate, making about ten different sounds at both conventional and ultrasonic frequencies. In addition, they have a unique hearing, which operates on the principle of an echo sounder and allows you to determine not only the distance to an object or object, but even its size and shape.
Dolphin is considered one of the fastest marine animals - in the water it can reach speeds of up to forty kilometers per hour! These animals are predators, they feed mainly on fish. The lifespan of a dolphin is about thirty years.
In the wild, many dolphins readily interact with humans. A dolphin saving its relative from danger will swim to the aid of a person in the same way. He will pull the drowning man ashore, drive away the shark from him, show the way to the sailors. This fact has long been proven, but the essence of this phenomenon has not yet been explained.
Do dolphins sleep?
Sleep is vital for dolphins - just like all other mammals. However, it is special in these animals. The observations made, as well as studies of the bioelectrical activity of the brain, made it possible to reveal a very definite picture of how dolphins actually sleep.
In order not to drown while sleeping or become a victim of a predator attack, these marine mammals sleep "half". One hemisphere of the animal's brain during sleep receives a good rest, while the secondcontinues to be awake, controlling what is happening around, and responsible for the respiratory function. That is why dolphins sleep with one eye open: if the right hemisphere of the brain is resting, the left eye is closed, and vice versa. This sleep takes about six or seven hours a day. And when the dolphin wakes up, both hemispheres are already at work.
How dolphins sleep
Unusual at first glance, the peculiarity of the "half" sleep of a dolphin does not prevent him from going through all the phases, from fast to deep, and at the same time provide the animal with a good rest. Scientists have closely monitored how dolphins sleep and have identified common patterns. This always occurs at shallow depths, near the very surface of the water. Due to the high content of adipose tissue in the body, dolphins descend very slowly. Every now and then the animal, while in a dream, hits the water with its tail and floats to the surface in order to breathe air. After that, it slowly sinks to the depth again.
Dolphin breathing in a dream
When the dolphin feels the change of environment when it comes up to the surface, the dolphin opens its blowhole (nostril). He breathes very quickly: due to the structural features of the respiratory tract, he is able to inhale and exhale at the same time. While under water, the blowhole remains securely closed with a tight valve.
Newborn dolphins don't sleep for a month
Studies have proven: the assumption that dolphinsnever sleep is a myth. However, another curious fact was discovered. Scientists at the University of California at Los Angeles have found that newborn cubs of dolphins and whales do not fall asleep at all during the first month of their lives! In addition, babies force their mothers to stay active all the time as well…
Tiny dolphins are constantly on the move, surfacing for air every three to thirty seconds. And only after a month, short periods of sleep begin to appear in their daily routine, which gradually approach the norm characteristic of an adult animal.
American biologists have suggested that this behavior reduces the danger for baby dolphins and whales to be eaten by predators, and also enables them to maintain a stable body temperature. In this regard, they raised an interesting question about the presence of a certain reserve in the body of mammals that allows them to go without sleep for a long time without experiencing harm to he alth.
