Brown Bear

Order:  CarnivoraBear Den photo

Family:  Ursidae

Genus:  Ursus

Species:  Ursus arctos

Where Found

Eastern and Western Europe, Northern Asia and Japan , Western Canada, and the states of Alaska, Wyoming, Montana, Idaho, and Washington


The brown bear’s coloration varies from dull brown, to almost black, to a yellowish white, and all variations of brown and red. The mixture of its fur coloration gives the fur a “grizzled” appearance, hence the name Grizzly.


Brown bear size varies depending upon population and diet. Adult males may weigh 300 to 860 pounds 136 to 390 kg). In the lower 48 states of the USA , the average weight is 600 pounds (272 kg). In Alaska and Canada , the average weight is 900 pounds (408 kg). Adult females weigh from 205 to 455 pounds (93 to 206 kg); in the lower 48 states, the average weight is 300 pounds 136 kg); in Alaska and Canada, the average weight is 500 pounds 227 kg). Birth weight averages 11 ounces to 1 pound 6 ounces 312 to 624 grams). Longevity in the wild can be as high as 30 years, but typically 25 years is an old bear.


Females reach sexual maturity at four-and-a-half to seven years of age. Males enter the breeding population at eight to ten years old, later than other species, due to size and competition with other males. Breeding occurs from early May to mid July. Delayed implantation results in cubs being born in January. The common litter size is two. Typically, cubs remain with their mothers for two-and-a-half years.

Social Life

Adult brown bears live alone, except for females with cubs. Sub-adult siblings sometimes travel together. Large groups gather where food is abundant, but respect other bears’ “personal space.” Adult males are the most dominant individuals in group situations. They communicate through complex forms of body language and vocalizations.


Approximately 85-95 per cent of the brown bear’s diet is from vegetation such as grasses, sedges, bulbs, and roots. Insects, fish (salmon being a favorite), small mammals, and carrion are also included in their diet. In some areas, brown bears will predate on moose, caribou, and elk.


The male’s home range is larger than the female’s. Grizzly bear habitat includes those areas that provide food, cover, and space necessary for survival and reproduction. Use of habitat typically shifts seasonally based on the changing availability of seasonally abundant foods (for example, grasses in spring, berries in late summer). Localized populations are found in Eastern and Western Europe, northern Asia and Japan , Western Canada, and the states of Alaska , Wyoming , Montana , Idaho , and Washington .


The largest brown bears are found on the west coast of British Columbia and Alaska , and on Alaskan islands such as Kodiak and Admiralty. Access to fish protein affects their size. Grizzlies can sprint as fast as 35 to 40 miles per hour (56 to 64 kilometers per hour), and climb trees. Many cultures have alternative names for the bear to show respect for the power of the animal: “Apple of the Forest” in Finland , “The old man with a fur coat” in Lapland, and “honey eater” in Russia . Both bears and humans are plantigrade; bears, like humans, walk on their entire foot rather than up on their toes.

photo credit:  ADFG/M. Riley

Project Initiatives

Bear trust focuses on 4 primary project initiatives:

  1. Conservation Education
  2. Bear Research & Management
  3. Habitat Conservation
  4. Conservation Policy

Contact Info

PO Box 10850
Bozeman, MT 59719
Phone: (406) 523-7779