Polar bear hibernation does not occur like black bear or grizzly bear hibernation. Black and grizzly bears, unlike polar bears, are true hibernators. Polar bears probably do not hibernate in a way they do. They just enter into a specialized winter dormancy. This is little different from natural hibernation. During winter dormancy polar bears can also reduce their heart rate and possibly metabolism and temperature. Let’s see how do polar bears hibernate.
Do Polar Bears Hibernate? – Polar Bear Hibernation
Female bears dig dens in snow and they remain asleep for 4 to 8 months. They become absolutely inactive during this period. Polar bears neither eat nor do they drink in fact they do not even urinate whilst they are hibernating. In spite of all this inactivity females appear to have stable mineral levels with a constant body mass.
Many researchers estimate the level of blood metabolites which is almost fully maintained. This is quite remarkable in that the animal loses half of its weight inside the den while maintaining the metabolite level stable.
During hibernation or dormancy polar bears make up the deficiency of water from fat catabolism. By so doing they are able to maintain stable fluid level within the body.
Read More: Polar Bear Den
Polar bears are probably the only animals within the Ursids family that have evolved to survive months in starvation. The body appears to respond in an ideal fashion and the bear is adapted to live like hungry animals. Although they lose half of their body mass polar bears can recover well when they emerge from the den.
Studies suggest that polar bears are able to regulate their metabolism in fasting periods. Researchers also believe that polar bears are the only bears that can transform into a hibernation-like state when the food is short.
Polar bear is believed to be the most advanced of all land mammals for being highly adaptive to water and food deprivation days.