Top priority is survival, and that always means adaptation. To survive freezing temperatures, life had to flee or adapt. Many species of birds chose to flee, and like wealthy and pampered humans, spend their winters in the tropics. These creatures are certainly not less fortunate. Adaptation was more difficult, but the results are nothing short of amazing.
Hibernation is a form of adaptation where the animal s metabolism slows down to very low levels.
The body temperature drops, respiration and heart rate are lowered, decreasing the need for food and water. The animal becomes unconscious and survives on the fat stored in its body. Animals prepare for hibernation by eating large quantities of food and seeking out a cave or protected spot to sleep in. Not all hibernating animals stay completely inactive all winter. Some animals' body contains a blood substance called HIT, hibernation induction trigger, which controls periods of waking up and eating stored foods in the den.