8 Amazing Facts About Grizzly Bears

The grizzly bear is a subspecies of brown bear found in North America. Most grizzlies are found in Alaska and Canada, with small populations in the western U.S. The bears range from blond to black in color and have a large, muscular hump on their shoulders. North American grizzlies have protection as a threatened species under the Endangered Species Act.

While not true hibernators, grizzlies are well known for eating large quantities of food in preparation for several months of slumber in their winter dens. From long gestation periods to impressive senses of sight and smell, here are a few things you may not know about the grizzly bear.

1. Grizzlies Are Surprisingly Fast

Though they look big, heavy, and lumbering, they can really hustle, hitting speeds up to 35 miles per hour for short bursts. That's why experts advise to never try to run away from a grizzly.

Grizzlies range from over three to nine feet in length, and an imposing eight feet tall when standing on two legs. Adult grizzlies typically weigh between 700 and 800 pounds, with some males weighing as much as 1,700 pounds.

2. They Go by Many Names

Grizzlies in North America are subspecies of the brown bear, Ursus arctos. While often referred to as brown bears, the North American grizzly bear is scientifically known as Ursus arctos horribilis; the Kodiak grizzly, Ursus arctos middendorffi; and the peninsular grizzly, Ursus arctos gyas. 

The light-colored guard hairs give the bear the common name of not only grizzly, but also silvertip.

3. North American Grizzlies Are at Risk

Once abundant throughout the western U.S., the grizzly population had been eliminated from 98 percent of its range in the lower 48 states when it was classified as a threatened species by the U.S. Fish and Wildlife Service in 1975. 

Decades of conservation efforts have helped bring the numbers back up a bit, with approximately 1,500 to 1,700 grizzlies in five populations in the continental U.S., mostly in Glacier and Yellowstone National Parks. While the increased population may result in removal from the Endangered Species List, continued conservation across the grizzly’s habitat is needed to keep their numbers from falling further.

4. They Have a Hump

Unlike black bears, grizzly bears have a distinctive hump on their shoulders. The hump is pure muscle — one that the grizzly needs to power its front legs for speed and to dig winter dens in its rocky mountain habitat. 

Their added forelimb strength also helps grizzly bears dig through dirt and brush to search for insects, plants, and roots.

5. They Take Eating Seriously

Grizzly bears are omnivores with a voracious appetite. They’ll eat anything from roots and grasses, to berries and nuts, fish and rodents, elk, and even carrion. Depending on their habitat and the season, they’ll eat the most plentiful foods available. 

Since they’re only active for six to eight months each year, grizzlies have to consume a lot of calories to store enough fat to make it through winter.

6. They Are Not True Hibernators

Grizzlies use the fat stores they build up in summer and fall to provide the energy they need to survive several months of winter in their dens. While they are not considered true hibernators, grizzlies spend winter in a state of torpor. They are able to awaken if necessary, but primarily remain in their warm dens without eating, drinking, or eliminating waste.

7. Grizzly Cubs Stay With Their Mom

Female grizzly bears don’t have their first cubs — which are born after a gestation period that lasts from 180 to 266 days — until they are between four and seven years old. The cubs, which are born tiny, blind, and helpless, weigh only about one pound at birth. 

The sow remains in the den with the cubs for several months until they are large and strong enough to explore the outside world. The mother grizzly continues to feed and protect her cubs for two to three years and does not breed again until they have separated.

8. They Have Several Modes of Communication

While grizzly bears are widely known for their sense of smell, these large mammals have several ways of interacting with each other and their environment. Grizzlies rely on sound — moaning, grunting, and growling — when communicating with mates or young offspring. They use trees to leave their scent behind to make other bears aware of their presence. 

A grizzly bear’s body language reveals a lot about how it’s feeling. When agitated, grizzly bears move their heads back and forth, make snorting sounds, and clack their teeth. Signs of aggression include lowering of their head, pushing their ears back, and holding their mouth open.