Every autumn bears of temperate and polar latitudes (in particular brown and black) begin to prepare for hibernation. All spring, summer and autumn, these animals actively fed, nagulivaya stocks of fat for the winter. And now, when the cold comes, they are looking for a suitable shelter in order to winter. After the shelter is found, the bear falls into a hibernation.
To understand what is happening in the body of a bear during hibernation, it is necessary immediately to clarify what the hibernation itself is. And why is it not “anabiosis” in the literal sense of the word. In the literal sense of this term, “anabiosis” is a process of complete inactivity of the animal. At this time, the level of metabolism is reduced to indicators, which for most higher animals are incompatible with life.
Some species of amphibians (some newts and frogs) freeze into frosts, without harm to themselves, thawing at the onset of a warm season. Painless this “freezing” literally through to them is in connection with the development of a specific substance that has the properties of antifreeze, which prevents the freezing of water in their body.
Bears do not freeze. The temperature of their bodies during hibernation remains high enough that they can wake up in case of any danger, coming out of the den. By the way, bears that woke up earlier than time are called “rods”. They pose a significant danger to humans, because in the winter the bear can not find enough food, and is always hungry and aggressive.