Wildlife

Brown Bear (Ursus arctos)

Brown bears tend to be larger than black bears. Brown bears are considered the largest living land carnivore. Though polar bears can be larger, they are not considered to be land dwelling. Brown bear sizes vary depending on location, time of year, age and gender. Most male brown bears range from 500 to 900 pounds. Color varies greatly from black with silver tipped hair to blonde. Males tend to be darker than females and cubs often sport a white collar during their first summer. Although the same species, Alaskans typically refer to coastal bears as “browns” and interior bears as “grizzlies”. The grizzlies of the Tetlin Refuge are smaller and lighter in weight than those in southern and western Alaska. Grizzlies occur throughout the entire Refuge at a low density, but are more abundant along the foothills and mountains.

Brown bears have a varied diet ranging from grasses in the spring, berries in the summer, and fish during the fall. Meat is not usually a major component of the bears’ diet but they will eat whatever they can catch which includes marmots, porcupines, squirrels, mice, moose, and caribou.

Breeding occurs May thru July and the cubs are born in January / February, weighing only 8 to 10 ounces. Litter size varies from one to four, with twins being the most common. Most females nurse their young for two summers, and then wean the cubs during the third.

Brown bears typically “hibernate” in dens during the winter months. Denning times can vary depending on location, snow levels, and temperature. While denning, the bears’ metabolism and temperature are lowered and their need for food and water are eliminated. Bears in colder climates remain in their dens longer and males typically emerge before females.

Last updated: March 11, 2011

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