A black bear chooses both caves and hollowed-out trees when seeking out a den for hibernation, according to the National Park Service. Brown bears dig their dens at the base of large trees surrounded by dense vegetation. Neither species of bear lives in the same location when not hibernating.
Hibernation provides bears with a way to survive the harsh winter season when food is scarce. The length of hibernation depends upon the climate where the bear lives and can range from a few weeks to more than six months in cold areas such as Alaska. According to the American Bear Association, bears in warmer environments such as Florida don't hibernate at all, as there is plenty of food available throughout the year.