What is Hibernation?
[[File:Eptesicus nilssonii hibernating.JPG|right|thumb|A bat ([[Northern bat]]) hibernating in Norway]] '''Hibernation''' is a time of inactivity. Some endothermic ([[warm-blooded]]) animals hibernate, usually during the [[winter]], when food is short. They fall into a sleep-like state. They regulate their [[metabolism]] to consume less energy. They lower their body temperature, slow their breathing, and slow other vital functions. During hibernation, the body uses [[fat]] for energy, which the animal has gathered in [[summer]] and [[autumn]]. They hibernate from the end of autumn to the start of winter. Animals try and eat as much as they can to increase the fats in their body. Mammals like [[bat]]s, [[ground squirrel]]s (like [[marmot]]s), [[hedgehog]]s, [[marsupial]]s and others hibernate. The phases of sleeping (called torpor) are different for the different animals. Hedgehogs sleep for 1–3 weeks, without waking, The [[Edible dormouse|fat dormouse]] sleeps for 20–33 days, without waking. The winter sleep of [[bear]]s is not as deep as hibernation. Only mammals hibernate. However, a few birds including [[hummingbird]]s do something similar. == Related pages == * [[Torpor]] * [[Dormancy]] * [[Aestivation]] [[Category:Physiology]] {{biology-stub}}