All grizzly bears are brown bears, but not all brown bears are grizzly bears.  “While there has been much confusion about the taxonomy of brown bears (Ursus arctos), taxonomists agree there are at least two subspecies in North America -- the grizzly bear (U. a. horribilis) and the Kodiak bear (U. a. middendorffi).  There is confusion about whether to consider others, like U. a. gyas and U. a. macfarlani, as separate subspecies.  The Kodiak bear has lived separately on Kodiak, Afognak, and Shuyak Islands in southwestern Alaska for thousands of years with no interbreeding with other populations.  However, there is no such geographic demarcation between the coastal U. a. gyas and the inland U. a. horribilis.  There is a continuum of difference between the larger coastal brown bears and the interior individuals that are generally called grizzly bears.  Coastal brown bears have a greater amount of animal protein in their diet, achieve larger size and have slight differences in coloration.  At any point from the coast to the interior there is interbreeding between the populations (Jonkel 1987, p 456-473).” (North American Bear Center www.bear.org )

 

 

Like many animals, grizzly bears spend a good part of their lives looking for food.  You will never see a grizzly bear on a diet; in fact, they try to gain a few hundred pounds of fat in the fall to prepare for winter hibernation.  Fortunately, grizzly bears are omnivores and will eat just about whatever they can find.  Their long claws make great tools to dig insects from logs, roots and bulbs from the ground, and small mammals from their burrows.  Grizzlies are big enough to take down large mammals like a bison or elk and quick enough to trap fish with their big front feet.  They will eat grasses, berries, and even dead animals, which their sensitive noses can smell from miles away.

Though hundreds of pounds of extra fat may seem like a lot, grizzlies need it.  During the cold winter, they sleep for five or six months without eating or drinking.  Instead, they get their energy from this extra fat.  By the time spring comes around, they are lean and hungry again! 

Grizzlies may use their long claws and strong muscles to excavate a den they can sleep in for the winter, but they often prefer caves or hollow trees.  Even though they do sleep most of the winter, they can be easily awakened and may go for a short walk on warmer days, so they are not true hibernators.