When the weather grows cold and the food supply finally dries up, they will retreat to their winter dens. Males bed down around mid-December and emerge in mid-March; females, which give birth during the winter and stay with their cubs for two years, remain in their dens longer, from late November to mid-April.
Do black bears hibernate all winter?
Bears hibernate during the winter months in most areas of the world. Duration of winter denning is dependent upon latitude and varies from a few days or weeks for black bears in Mexico to 6 months or more for bears in Alaska (Kolenosky and Strathearn 1987, Haroldson et al. 2002).
Does hibernation mean sleeping?
Despite what you may have heard, species that hibernate don’t “sleep” during the winter. Hibernation is an extended form of torpor, a state where metabolism is depressed to less than five percent of normal. … This is very different from sleep, which is gentle resting state where unconscious functions are still performed.
Do bears give birth during hibernation?
Cubs are usually born within the first two months of hibernation. Cubs and their mothers stay in their dens for the rest of the winter while the mother bear rests and the cubs nurse and grow. Females and their cubs usually emerge from their winter dens in late March or early April.
What triggers hibernation in bears?
Bears enter a lighter state of sleep called torpor. Hibernation is a voluntary state an animal enters to conserve energy, when food is scarce, and minimize exposure to the winter elements. … Hibernation is triggered by decreasing day length and hormonal changes in an animal that dictate the need to conserve energy.
How do bears know when to come out of hibernation?
The signal to wake up comes from inside. Hibernators have an internal clock, a series of chemical reactions controlled by the hypothalamus of the animal’s brain. … The shorter days and cooling temperatures of autumn set its clock to time zero. The animal goes into hibernation, then wakes up about 180 days later.