"Why do bears hibernate" Bears hibernate to survive during harsh winter conditions when food is scarce. Hibernation allows bears to conserve energy and reduce their metabolic rate. During this period, their heart rate, breathing, and body temperature decrease, enabling them to live off stored body fat. Hibernation also helps them avoid cold temperatures and reduced food availability. Bears typically find a sheltered den, such as a cave or hollow tree, where they spend several months in a dormant state until spring when food sources become abundant again.