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Grizzly bear

Scientific name: Ursus arctos horribilis

CLASS: Mammalia
ORDER: Carnivora
FAMILY: Ursidae

STATISTICS: Weight: 650 to 1,200 lbs.; Height: up to 8 ft

The grizzly bear has a hump of muscles atop its shoulders, while in the black bear it is located further back. The grizzly’s thick coat ranges in color from off-white, tan, yellow, and brown to black. The name grizzly comes from the grizzled gold coloration that appears on the tips of the fur as the bear matures. It has a concave face and a very short tail. Canine teeth may be up to three inches in length. Front claws can reach up to six inches and are curved.

Mainly in the western half of North America

Mountainous terrain, alpine meadows and coastlines

Grizzly bears have a keen sense of smell and hearing, but their eyesight is poor. A heavy, fleecy undercoat and coarse guard hairs protect grizzlies from the cold. The shoulder hump is composed of fat and muscle. Their dentition and powerful jaws allow for a varied diet. Claws are used for digging and marking territory by slashing tree trunks.

Grizzlies can swim well, and can run up to 30 mph on land for long periods of time. Although generally solitary, grizzlies are the most social of North American bears, occasionally gathering in large numbers at major food sources, and often forming family foraging groups with more than one age class of young. Only cubs climb trees.

Grizzly bears are not true hibernators, but instead experience a period of dormancy from October-December through March-May. During this period the bear’s heart rate is low but their body temperature remains elevated and they can be easily woken. During true hibernation, it is very difficult to wake an animal. Before going dormant, the bear will look for a den, which may be a natural den or one dug by the bear to rest in.

Breeding occurs in May or June. Cubs are born helpless in December or January, but grow rapidly and leave the den with the mother at three to four months of age. They leave their mothers between one and two years, reaching sexual maturity at three to four years, and full growth at eight to ten years. No lasting social bonds are present except those between females and young.

Prey to humans
Predator to any smaller animals - top of food chain.

The grizzly bear is listed as Least Concern with IUCN. It is also listed on Appendix II of CITES.

It has been eliminated from parts of Canada, Mexico, and the United States, and has some protection as a threatened species in the South of Canada. With increasing loss of habitat and growing human presence in the northern Rockies, grizzly survival is becoming more dependent on human actions for protection.


  • Most human attacks involving grizzlies are related to either mothers protecting cubs, grizzlies raiding campsites for food, or territory defense.
  • Often referred to as the most dangerous animal in North America, if you disregard venomous insects, disease-spreading rodents, domestic animals, and people, this may be true. Average weight of the grizzly is twice that of the black bear.


  1. CITES. October 2008.
  2. IUCN. October 2008.
  3. Novak, Ronald M. Walker’s Mammals of the World. Vol I. Baltimore, Maryland. The Johns Hopkins University Press. 1991

Published: February 2009

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