Most parasites of bears are adapted to their host’s hibernation cycle and reduce their demands in winter.Medical researchers are studying black bear hibernation to learn how bears cope with conditions that are problems for people. Bears do not usually die of starvation in dens, most deaths from starvation are before or after hibernation and involve primarily cubs and yearlings. Their main threats are flooding and predators (wolves, dogs, active bears, and humans). Less than 1 percent of black bears die in dens. Maintaining the brain at a high temperature enables bears to maintain brain function for tending newborn cubs and responding to danger. Only the head and torso are maintained at the high temperatures. Description The black bear is a stocky animal with short, thick legs. Bears can maintain this high body temperature despite their slower metabolism in winter because they develop highly insulative fur and reduce blood supplies to their limbs. Rectal temperature drops only slightly, though, from 99-102 degrees F in the summer to 88-98 degrees F during hibernation. Sleeping heart rate drops from a summer rate of between 60 and 90 beats per minute to a hibernating rate between 8 and 40 beats per minute. To survive long winters without eating, drinking, exercising, or passing wastes, hibernating bears cut their metabolic rates in half. When people defined hibernation simply in terms of temperature reduction, bears were not considered hibernators. Bears that find food year-round in the South may not hibernate at all. Do Black Bears Hibernate Short answer: yes. Hibernation lasts up to 7 months in the northern regions but is shorter in the South. Most bears use a different den each year. They sleep alone except for mothers with cubs. Bears gather leaves, grass, and twigs to make isolative beds on which to curl up, leaving only their well-furred backs and sides exposed to the cold.

Dens may be burrows, caves, hollow trees, or simply nests on the ground. Bears do not urinate or defecate during denningthey recycletheir waste into proteins and other nutrients. Most dens are nearly as cold as the surrounding countryside. This drowsy condition allows bears to defendthemselves (and their cubs) more effectively should a predatorvisit the den. For the black bear, hibernation is more an adaptation for escaping winter food scarcity than an adaptation for escaping winter cold.

Do bears hibernate