Black bears in the Sierra Nevadas typically `` den '' from December through early spring . But some emerge from hibernation early in what 's been called a `` disastrous winter '' where they are unable to find food or water and starve, often dying of starvation before reaching their normal weight for mating season. Even though it 's warmed up , the bears climbed up to 1,000 feet to den in snowy and icy spots Official : It 's also been unusually warm in Alaska , but bears there so far have stayed put .
Black bears in the Sierra Nevadas typically `` den '' from December through early spring . But some emerge from hibernation early in what 's been called a `` disastrous winter '' where they are unable to find food or water and starve, often dying of starvation before reaching their normal weight for mating season. Official : It 's also been unusually warm in Alaska , but bears there so far have stayed put .