The hibernation is a state of lethargy that allows mammals to withstand the rigors of the cold. When an animal hibernates, its body is produced in a series of physiological changes, such as reduced metabolic activity, lower body temperature and decreased heart and breathing rhythms. A large part of your body stops, and the movements are almost nil. For example, when a squirrel hibernates, breathes four times per minute, while it does in a normal state between 100 and 200 times, and his heart beats 10-20 times per minute instead of making beats 200-300. During the winter, many animals use to sleep, or go into torpor, a state similar to hibernation, and thus overcome the low temperatures and food shortages.
When you start the winter, bats seek caves for shelter during the period of hibernation, consume its fat reserves and low body temperature to two degrees below zero.