Animal Hibernation Explained: How It Works and How Long It Lasts.

The little creatures of the woods and fields that go to sleep during the cold winter months are very thankful to Nature, who allows them this privilege. This long sleep, or hibernation, as it is called, begins when the food of the drowsy animal becomes scarce. The length and soundness of the sleep depend on the habits and constitution of the creature. Some sleep the whole winter through, while others indulge in short naps, wakening every now and then to store up with food which they have taken care to make secure in their “larders.”

Most animals retire for this sleep to dark places of concealment, such as caves or holes in trees. While sleeping, there is a great decrease in the temperature of their bodies. In some cases, it sinks to 40 degrees or even 20 degrees F., usually keeping to a point just above that of the surrounding atmosphere. Breathing as well as the pulsation of the heart is very slow, and the hibernating animal is so “dead to the world” that the only way it can be awakened is by strong electric shocks.