How the bear sleeps all winter in a den, many fairy tales and songs are put. Even kids know that for the winter the bears fall into hibernation. But about why they do it and how exactly it occurs, know not many.
Why the bear sleeps in the winter?In the world a set of species of bears, but those who live in climatic zones from moderated to Arctic fall into hibernation. It happens because of features of food of animals. In these zones the snow lays down a dense layer and for long time in the winter. The bear – the largest predator on the earth, the weight of animals hesitates from 150 (small individuals) up to 750 kg. Such huge animal needs a large number of food.
By and large, the bear is omnivorous, but in the winter he is deprived of vegetable food, cannot catch fish in the frozen rivers, and in connection with strong fall of temperature also organism energy consumption raises. For this reason not to starve to death, bears fall into hibernation.
Hibernation – just a dream?Hibernation is the special physiological process similar to very deep sleep. Before hibernation the animal reserves nutrients in the form of fat which makes up to 40% of body weight. Then he looks for the shelter with a good microclimate – in a case with a bear it is a den. During hibernation all processes – blood circulation, breath, food, etc. – strongly slow down. What is interesting, hibernation of bears it is impossible to call that in the true sense of the word. Their metabolic processes decrease not so strongly, as at other "sleeping" animals. At some rodents, for example, body temperature during hibernation can fall to - 2 wasps. At a bear it decreases only from 37 to 31 wasps.
When during hibernation the body temperature of a bear reaches the minimum point, the bear begins to tremble all over that it is a little to raise of it.
And if to wake a bear?About strongly not the well-rested person joke that he is similar to a bear connecting rod. Actually, ridiculous in it it is not enough. A bear connecting rod – a show terrible and really heart-breaking. So call those bears who for any reasons did not lie down in hibernation or woke up too early. Such phenomenon can have different reasons, but the most frequent is a crop failure of nuts and berries. The animal does not manage to save up necessary reserves of fat for the winter therefore cannot sustain long hibernation. The wild, gone mad for hunger bear goes on the wood in search of livelihood. The person who occurred in his path is in danger of death. In most cases such bears do not live up to spring, perishing from exhaustion.
Not so long ago American scientists found out that bears during hibernation wake up once a day to correct the laying and it is more convenient to settle.
Whether any bear sleeps?Unlike brown, at polar bears only she-bears with bear cubs fall into hibernation. The polar bear to some extent was lucky more – even in the coldest season he can catch fish and fill a reserve of nutrients at the expense of seal fat.