American scientists, together with colleagues from South Africa found that African elephant hardly spend time to sleep. Biologists have long conducted surveillance of two wild female elephant, and found that they slept only two hours a day. Among mammals, creatures it is an absolute record.
Scientists have for many years interested in the details of the physiology of large and unique animals like elephants. The first experiments related to the period of sleeping elephants were put back in the thirties of the twentieth century. Then the experts found that the largest mammals of the planet prefer to sleep at night, an average of 4-6 hours a day. But the results of these studies were wrong, because scientists have studied especially the elephants living in captivity. Biologists have long known that virtually any animal, being in captivity, in the presence of food and drink, sleep longer than in their natural habitat.
Modern scholars have come to study more carefully: they watched the wild females, living in Botswana. Elephant wore catchers devices with GPS, gyroscopic devices and their trunks were attached actigraphy - apparatus, locking the frequency of physical activity for a certain period of time.
Just estimate the duration of sleep, analyzed the brain activity of the animals, scientists could not. The fact that elephants have a very thick skull, and was not easy to implant electrodes in it.
According to the results of previous experiments, scientists have known that the motor activity of the trunk is always true indicates that the animal is awake or put to sleep. So they decided that the elephant is in sleep state, if the trunk is stationary for 5 minutes or more. Long-term observations allowed to determine that the average duration of sleep of an elephant was 2:00. However, their sleep was interrupted - for 20-60 minutes with short breaks.
Under extreme conditions, when the animals had to travel long distances, fleeing from persecution or in search of food, they can go without sleep up to 2 days in a row. However, their continued sleep did not differ from what was to travel.
In addition, experts have identified and the position of an elephant during sleep. It was found that 70% of an elephant standing prefers to sleep, and only occasionally falls.
Zoology expert John Lesko, representing the Australian La Trobe University, expressed his opinion that it is important to determine the optimal position of the animal during the different phases of sleep. "For example, many cloven-hoofed mammals sleep standing up, with half-open eyes, and thus even chew food. Therefore, it is likely that elephants sleep too long, but their appearance and movements do not create such an impression. "
However, the alleged duration of a night's rest at the elephants was recorded and is still the shortest among all groups of mammals. Other well-known large mammals withdrawn to sleep a lot more time.
If a person has pain in a dream, this is rarely seen as an independent problem. Often, it has an exclusively speculative, everyday character that points to sleep as a physiological phenomenon that facilitates and heals.