During the winter months, several animals experience a deep sleep in which they conserve energy just waiting for the warmer temperatures that are experienced in spring. This process is called hibernation. Getting ready for hibernation, the animal stores up fats, carbs and essential proteins that are necessary during to coldest months of the year while sleeping. Bears are probably most well known as hibernators, but there are other animals in Indiana that experience hibernation. In our area the groundhog experiences hibernation. Groundhogs can lower their heart rates from the normal 80 beats per minute to about 4 to 5 beats per minute.
Another mammal that experiences a deep sleep is the skunk. Although it is not called hibernation, the skunk goes in and out of the deep sleep during the cold months of winter. Preparing for this sleep time, female skunks can form communal dens to rest until breeding season starts. These dens can house several females. Communal dens have been known to have numbers from 8 to 10 females and in some cases closer to 20.
Torpor on the other hand is a form of lighter sleep that animals experience during cold winter months. Shrews, some mice, and ground squirrels (aka chipmunks) have the ability to slow their metabolic rate down to conserve energy. Animals that experience torpor can come in and out of sleep as the need arises such as the need for food or water or when the temperatures rise.
Both hibernation and torpor are nature’s way to protect animals during harsh conditions when temperatures are cold and food supplies are limited. Bats, turtles, and frogs also use these survival techniques.