How dolphins sleep: photos and interesting facts
Scientists rightly say that dolphins are one of the smartest animals on the planet. Not only individuals grown in the dolphinarium pools, but also those who live in the wild all their life, are easily contacted by humans. As if sensing some kind of kinship, these smart mammals more than once saved drowning people, and they themselves often turned to human for help, feeling the danger.
In the world there are many organizations that study the habits, customs and physiology of these funny creatures. But dolphins are not in a hurry to reveal all their secrets to humans. We still do not know much about them for sure. Even the simple question of how dolphins sleep, has long caused many controversial disputes. Today, science has not answered him. But who knows? Perhaps we are coming new discoveries about the dream of dolphins?
People of the sea
It is no coincidence that dolphins are called sea people. They look like people much more than it might seem at first glance. Dolphins, like us, make friends and friends, choose spouses, take care of the little ones, keep in touch with their relatives.Scientists have proven that these smart mammals are one of the few animals that can do something not only for practical use, but also just for fun. Perhaps that is why many dolphins love to speak to the public.
But still the differences are obvious. Air-breathing dolphins live in the water. This fact allows us to answer the question of why dolphins do not sleep like we do. After all, they have to rest in their native element, they will not get out on dry land. And the underwater world, as is known, is full of dangers.
Dolphin Dream Myths
More recently, many scientists have been inclined to think that dolphins are not sleeping at all. Today, it is often possible to hear versions of how the dolphins sleep half. Causes a lot of controversy and sleep newborn babies.
For the sake of justice, it is necessary to recognize that all these myths somehow correspond to reality. And they arise from the fact that the dolphin's sleep is very different from the sleep of other mammals.
The ancestors of all now existing terrestrial animals once left the ocean and, in the process of evolution, acquired an appropriate respiratory system.But the ancestors of all cetaceans, including dolphins, made this transition twice, returning to the aquatic environment back in time immemorial. But their lungs remained. Therefore, dolphins receive oxygen from the air, as we do, and not from water, like fish.
Answering the question about how dolphins sleep, one should be aware of the threat of drowning, which will inevitably come if the animal completely loses control of the situation. The dolphin can hold its breath for a long time, but not enough to "turn off" for several hours.
In addition, the underwater world is full of other dangers. Sea predators are not averse to eat fresh meat.
That is why nature has developed a cunning mechanism. The dolphin falls asleep with a “halfway” sleep, during which only part of the brain turns off, alternately. One hemisphere is awake when the second rests. Therefore, we can say that dolphins sleep with one eye open, assessing the situation around them and not forgetting to come up with a portion of oxygen.
Dolphins prefer to fall asleep not in the open ocean, but in the shallows. This gives them the opportunity to protect themselves from encounters with sharks, and from excessive diving.
Trying to describe this state, scientists describe the moment of falling asleep. The human brain enters the phase of sleep gradually. Perhaps everyone noticed that before the dream the perception of reality had not yet died away, but wonderful images, clear precursors of dreams, had already begun to emerge in my head. At such a moment, a person is able to quickly wake up from any rustling, if he seems dangerous. But at the same time, in this phase any harmless noise (for example, conversations or a working television) may not interfere at all. Something like that is experienced by a sleeping dolphin.
What are dolphin dreams?
Once it was believed that the ability to see dreams is endowed with only a reasonable person. But to refute this belief, it is enough to observe a sleeping dog or cat. The beast can show anxiety, make movements, moan. This clearly indicates that some kind of brain activity occurs during sleep. It is caused by nothing more than a dream.
Of course, these observations are not enough for zoologists and sleep specialists. Therefore, the theory that animals dream of dreams is based on scientific experiments, research, facts.Cetaceans are no exception. Dreams sees and sleeping dolphin.
Photos of these amazing animals, blissful in a dream, sometimes eloquently confirm that dolphins are experiencing emotions. True, their dreams are not as vivid and plot as those whose brain goes into sleep mode entirely. After all, one hemisphere of a dolphin, as we already know, is always on the alert.
Surprisingly, the myth of the complete absence of sleep also has partial confirmation. Scientists at UCLA have shown that the ability to fall asleep appears about a month after birth. Newborn dolphin does not sleep at all.
This fact makes one more point to think. As you know, dolphins are sensitive and caring parents who care for babies. It is impossible to imagine a constantly awake baby next to a sleeping mother. For a long time after birth, the female dolphin is not sleeping either. Today, scientists are trying to thoroughly study how dolphins sleep. On the question of dolphins who have recently given birth to babies, they are inclined to believe that certain hormones associated directly with childbirth and feeding help them not to sleep.
How do other cetaceans rest
Dolphins are not alone in their unusual way of recreation. Absolutely the same process occurs in all their close relatives. Sperm whales take a vertical position in which the head is closer to the surface. Greenland and blue whales are drifting like dolphins, trying to keep closer to the shallows.
All members of the family sleep "half", alternately disconnecting the hemispheres.
If you are interested in how dolphins sleep, the photo will help to partially quench their thirst for new knowledge. But even more informative can be a visit to a dolphinarium or an aquarium where you can look at sleeping animals.