The brown bear is a mammal belonging to the genus Ursa in the family Ursidae. He has a strong physique, with raised shoulders and a short tail behind him. The fur color is mostly brown or brownish yellow; Elderly individuals appear silver gray in color; Childhood is brownish black. The lifespan under wild conditions is 20-30 years. The earliest ancestors of bears were all canids. After evolving into bears, they relied more on fruits for food and were prone to food shortages during winter. To survive, hibernation was undoubtedly the best way. The only mammal that can go six months or even longer without eating, drinking, urinating, or defecating. The energy needed to maintain necessary bodily activity during winter comes from stored fat in the body.