Young grizzly bears learn what to eat from their mother. Nuts, berries, insects, salmon, carrion and small mammals can all be part of a grizzly's diet. Type of food eaten depends a lot on the habitat. Grizzlies in areas of Alaska eat primarily salmon, while grizzlies in high mountain areas eat mostly berries and insects. Moths have been found to be a vital protein source for bears in Montana.
Bears hibernate during the winter, usually digging their own dens with their claws.
They will often choose the side of a slope where snow collects, providing good insulation. Grizzlies need to eat a lot in the summer in order to survive through a winter of hibernation. If a grizzly does not eat enough before winter, it might not survive through hibernation. The grizzly only defends it's breeding territory, and the mothers fiercely guard their cubs. Bears live by themselves except during the mating season.