What is Hibernation?
It is an inactive state in endothermic animals, characterized by low metabolic rate, low body temperature, slow breathing and heart rate.
It is a winter survival strategy in animals. It becomes very difficult for some animals to find food in winter because the main source of their food like plants and insects becomes short in supply. These animals solve this problem by deep sleep (hibernation) which helps to save energy in winter months without eating.
Hibernation in Animals
Some common hibernating animals are skunks, bears, snakes and bats. These animals usually move to a burrow or a den for shelter. Once they undergo deep sleep, it is very difficult to wake them up.
Before hibernating, animals need large amounts of food which will add to their body fat to help them continue their deep sleep without eating. And when they wake up after hibernation they are very hungry because the entire fat reserves are already used up.
While bears are not considered the true hibernators because they may wake up many times during hibernation and they do not lower their body temperatures as much as other animals do.
Hibernation in Birds
Historically it was believed that some birds also hibernate but now it is said that birds usually do not hibernate. But Phalaenoptilus nuttallii known as common poorwill is an exception to this.
Types of Hibernators
According to the hibernating behavior animals are classified into two main types that are:
Those animals which hibernate no matter the food is available at that time or not. Hedgehog, lemurs, ground squirrels and other rodents hibernate annually and spontaneously.
These animals undergo hibernation only if there is the shortage of food or there is the extremely cold environment. The white-tailed prairie dog is an obligate hibernator while its close relative black-tailed prairie dog is the facultative one.