Winter season introduces many changes in the way animals live and survive, such as the activity of migration by whales, seals, turtles, eels, crabs, fish, butterflies, etc. Hibernation is also a popular term used while referring to the peculiar behavior of animals during winters. Basically, animals resort to hibernation in order to escape from the chillness of the winter season. They use it as a medium for preserving the energy and heat in their body, which is assisted by their own body system.
True hibernation is a dormant sleep-like state, which some animals enter into, during the winter season. The body of the animal also goes through a number of changes during the process, such as the body temperature becomes lower than normal and the heart beat and breathing slows down tremendously. Talking about bears, they do not experience true hibernation. Rather, they go through a state of ‘winter lethargy’, which in general terms is called hibernation. During this state, the body temperature of a bear stays quite normal. To know why bears hibernate, check out the following lines.
Reasons For Bear Hibernation
In the winter season, bears generally cuddle into a cave, holes that they have dug beneath trees, or even in a hollowed out tree, in order to hibernate. This shields them from other animals. It is extremely difficult for bears to find enough food like nuts and berries in winters, and therefore, they go into hibernation to save their energy. The basic purpose of hibernation is to bypass the winter season, during which the food supplies get restricted. Thus, in order to conserve energy, bears do not eat, defecate or urinate during winter lethargy.
Some Facts About Bear Hybernation
- Bears are not true hibernators. Some of them wake up and prowl around for a few hours or days at a time, in the winters as well.
- The hibernation cycle can be considered as a unique adaptation of nature, allowing many animals, apart from the bear, to survive the severe conditions during wintertime.
- Bears enter the winter lethargy state gradually and do not awaken until disturbed. However, if a bear is dormant, it is quite easy to awaken him. This is a contrast with true hibernators, which are hard to wake-up and enter dormancy quickly.
- The grizzly bear does not enter its den for hibernation until the onset of a blizzard, the one that would cover its tracks as it enters the den. This serves as a protection to the bear during hibernation, as no one would be aware of the fact that a bear is sleeping there.
- Before entering their dens for winter lethargy, bears gain considerable amount of weight, of about 40 pound per week. The accumulated fat is the only source of energy that fuels their metabolic activity, providing its fluid needs.
- When the bears come out of their winter lethargy, they are much thinner than when they entered. In fact, bears lose about 15 to 40 percent of their muscle strength during their food-less, three to four month hibernation.
- The female bears have cubs during the winter hibernation. Although the bear does not eat or drink anything, she is capable of nursing and caring for her cubs. Also, the tiny offspring usually weighs a pound or two at birth, so it is easier for the bear to nurse it.