Biologists told about supershort dream African elephants
Much sleep is harmful even elephants. These giant animals sleep on average two hours a day, making them the most famous “sleepless” mammal inhabitants of the African Savannah.
Elephants are so few do not sleep because they do not want more, and because the wild is full of danger. In captivity these animals sleep from three to seven hours, because in the next bushes are not hiding aliens with guns, and food that gets easy, no one to take will not.
Paul manger of the University of the Witwatersrand in Johannesburg (South Africa) and his colleagues studied the sleep of elephants in Chobe national Park in the North of Botswana.
The most reliable way of fixing the sleep is the recording of the electrical activity of the brain, but in the case of elephants, this scheme doesn’t work: they are too thick bones of the skull, so fixed on the minds of the electrodes ineffective, and placing them under the skull requires invasive intervention.
Not to unnecessarily injure the animal, the researchers installed motion sensors on the trunks, which are the most active part of the body of the elephant and are rarely alone, if the animal is awake, reports New Scientist.
The study lasted 35 days. It turned out that elephants sleep on average two hours, but not entirely, and in parts, that is were in polyphasic sleep between 1:00 to 6:00. In fact, the animals were Napping in the road, stopping briefly. They traveled long distances — about 30 km, probably trying to get away from lions or poachers.
Although the sample size is extremely small (only two females), Munger believes that the results of the study give an adequate representation of the typical habits of the wild elephants.
In addition, elephants are wearing collars with gyroscope, with which scientists have identified, lying or standing animals sleep. It turned out that fit the elephants literally only for 10 nights from 35. While researchers find it difficult to answer whether enough elephants such a severe sleep in order for their brain to function properly.
Large animals, said Munger, as a rule, sleep a little, because the greater part of the day to spend on food and its digestion: elephants can eat up to 300 kg of food per day. First she needs to find, and then thoroughly chew and digest — to sleep is very little time.
But even among the larger mammals there are Sony: for example, gray whales sleep for 9 hours a day, and giraffes. The horse, which needs three-hour rest, manage to chew gum in my sleep. It is therefore possible that ultrashort sleep elephants really enough for a full recuperation.