Hibernation

Hibernation is a way for many creatures - from butterflies to bats - to survive cold, dark winters without having to forage for food or migrate to somewhere warmer. 1 , they turn down their metabolisms to save energy. Animals in hot climates also 2 a form of hibernation called aestivation. This works in a similar way and enables them to survive extreme heat, drought or lack of food. Hibernating is much more 3 than simply sleeping, though. Depending on the species, it can vary from long, deep unconsciousness to light spells of inactivity. But hibernation carries risks as the dormant animal is 4 to predators and the unpredictable climate.