Do all bears hibernate?

Most bears hibernate in winter, but bears are not really hibernating animals.

Bears maintain a fairly high metabolic rate and can wake up without a long warm-up. When it gets warmer, they will wake up. Before hibernating, bears will eat a big meal and then find a cave or tree hole to avoid winter.

Lack of food is the main reason why animals hibernate. If there is enough food, many bears don't hibernate, but hunt all winter. But when there is not much food, bears will hide in caves for the winter. When small mammals hibernate, their body temperature will drop rapidly, but the bear's body temperature will only drop by about 4 degrees, otherwise the heart rate will slow down by 75%. Once the bear begins to hibernate, its energy source changes from diet to fat stored in the body.

Extended data hibernating animals

An animal on earth that can control its body temperature is called a warm-blooded animal. Animals whose body temperature can be regulated by the change of environmental temperature are called thermogenic animals. When winter is cold, their body temperature drops and their activities stop. At this time, their energy consumption is also reduced, so they can maintain their lives without eating food.

There are three types of hibernation. The first is the hibernation of amphibians and reptiles such as snakes and frogs, whose body temperature is in harmony with the surrounding environment. If the ambient temperature drops and the body temperature drops, it will go into hibernation and cannot be adjusted. ?

The second kind of animals, such as squirrels, usually keep their body temperature constant. During hibernation, they can lower their body temperature to the temperature close to the surrounding environment, but in order to avoid freezing body fluids below 0℃, their body temperature is maintained at about 5℃. ?

The third kind is a bear. When a bear hibernates, its body temperature drops by only a few degrees, but it can sleep without food for a long time, which should be close to between sleep and hibernation under strict classification.

Reference Baidu Encyclopedia-Hibernation