DURING the cold winter months, nothing seems more inviting than a warm bed. But for some animals in the wild, crouch down in their comfort zone when the nights are long and the temperatures are low is not just a matter of temporary comfort, its necessary for survival. Certain animal like bears and squirrels have evolved an adaptation that allows them to weather long stretches of time when the food is limited, they enter a state known as hibernation.

Hibernation is when animals “sleep” through the winter. An animal hibernates is much more dramatic than simply curling up for an extended nap, extreme metabolic changes are taking place. The animal’s heart and breathing rates slow down and its body temperature drops. This is because when the food is limited, an animal may use up more energy maintaining its body temperature and in searching for food than it would receive from consuming the food.

How long they are going to be like this? Well depending on the species, days or even weeks may pass without the animal waking to drink, eat or relieve itself. During the hibernation state, some animals will not wake up when they hear a loud noise or even if they are moved or touched.