皇冠体育app官网平台

Description

The grizzly bear is a subspecies of brown bear. Many people in North 皇冠体育app官网平台 use the common name “grizzly bear” to refer to the smaller and lighter-colored populations that occur in interior areas and the term “brown bear” to refer to the larger and typically darker-colored populations in coastal areas. However, most of these bears are now considered the same subspecies.

North 皇冠体育app官网平台 also has a second subspecies of brown bear: the Kodiak bear, which occurs only on the islands of the Kodiak Archipelago in the Gulf of Alaska. Although these are the only two subspecies in North 皇冠体育app官网平台, brown bears also occur in Russia, Europe, Scandinavia, and Asia.

Grizzly bears range in color from very light tan (almost white) to dark brown. They have a concave face profile, short, rounded ears, and a large shoulder hump. The hump is where a mass of muscles attaches to the bear’s backbone and gives the bear additional strength for digging. They have very long claws on their front feet that also give them extra ability to dig after food and to dig their dens. They usually dig a new den every year.

Grizzly bears can weigh upwards of 700 pounds (315 kilograms). The males are significantly larger than the females and on average weigh 200 to 300 kilograms (about 400 to 600 pounds). A large female can weigh 110 to 160 kilograms (about 250 to 350 pounds) in the lower-48 States.

Range

Historically, grizzly bears occupied a vast range across North 皇冠体育app官网平台, from Alaska to Mexico and from the Pacific Coast to the western Great Plains. In the contiguous United States, they have been eliminated from approximately 98% of their historical range, now persisting in fragmented populations in parts of Montana, Wyoming, Idaho, and Washington.

Grizzly bears are adaptable to various habitats, including woodlands, forests, alpine meadows, and prairies. They often favor riparian zones along rivers and streams, which provide abundant food resources.

Diet

Grizzly bears are omnivores whose diet changes dramatically with season, region, and available resources. Despite their formidable strength and reputation as apex predators, most of a grizzly’s diet is plant-based. In many inland areas, vegetation makes up as much as 80 to 90 percent of their intake. They forage widely for roots, tubers, grasses, sedges, and forbs, especially in spring when emerging greenery is most abundant. Summer brings a feast of berries—such as huckleberries, buffaloberries, and strawberries—which grizzlies consume in large quantities to build up fat reserves.

Grizzlies are also opportunistic hunters and scavengers. When it comes to animal matter, they feed on everything from ants and army cutworm moths to small mammals like ground squirrels, marmots, and voles. Their digging strength, aided by long, curved claws and a massive shoulder hump, allows them to extract hidden prey from burrows or rotting logs. In regions where fish are accessible, grizzly bears are expert anglers.

Large mammals are an important seasonal protein source. Grizzlies will hunt or scavenge ungulates like moose, elk, deer, caribou, and even bison, with calves and weakened adults being most vulnerable. Carrion, including winter-killed animals or leftovers from other large carnivores such as wolves or mountain lions, is readily consumed.

Life History

Grizzly bears are generally solitary and territorial, except for mothers and their cubs or when a plentiful food source is discovered. They are known to congregate at rivers during fish spawning events, especially during the salmon run in Alaska, and at improperly fenced garbage dumps. In these situations, large bears dominate smaller individuals.

Grizzly bears hibernate in dens during the winter to minimize energy expenditure at a time when natural foods are not available and to permit their tiny young to be born in a warm and secure environment. Throughout the summer and autumn, grizzly bears build up fat reserves by consuming as much food as they can find and can gain up to 400 pounds during this time. In late fall or winter, the bears find a hillside and dig a hole to serve as their winter den. When inside the den, grizzly bears slow down their heart rate, reduce their temperature and metabolic activity, and live off stored fat reserves. Pregnant females give birth in the dens and nurse their cubs until they are large enough to venture outside in the spring as snow melts and new food become available.

Depending on the length of the winter season, grizzly bears can stay in their dens for up to seven months. Pregnant females are the first to enter dens in the fall followed by females with cubs; solitary males enter dens the latest. In the spring, solitary females and males are the first to exit dens. Females with second or third-year cubs emerge a little later, and females with newborn cubs are the last to leave their dens after winter.

Grizzly bear hibernation is not as deep of sleep as some other hibernators, like bats or ground squirrels, and they will quickly wake up when disturbed.

Grizzly bears begin to look for mates in the spring and early summer. Females can mate with more than one male during her breeding season. When a female grizzly becomes pregnant, the development of the embryo temporarily stops for several months, a process called “delayed implantation.” Delayed implantation is characteristic of all bear species and some other families of carnivores, including weasels and seals. If a female bear is unable to gain enough weight during the summer and fall, her body will end the pregnancy, and the embryo will break down and be reabsorbed. This gives the female bear a head start on gaining enough weight to have a successful pregnancy the following year. When female grizzly bears enter hibernation, the embryo implants in her uterus and begins gestation. In January or February, female grizzly bears give birth to one to four cubs (usually two). The female will care for her young inside the den until spring, when they finally step out into the world.

The mother cares for her young for at least two more years, feeding and protecting them. When the cubs are two and a half years old, they typically separate from their mother. In areas with little food, the cubs may stay with their mother longer. Typically, separation happens when the female enters breeding condition and attracts males, which can be a threat to the cubs. At around five years of age, grizzly bears reach sexual maturity.

Grizzly bears can live to be 30 years in the wild, but most die before age 25.

Conservation

Grizzly bears are federally listed as threatened. While some populations are stable or even thriving, their overall population has significantly decreased from historic levels due to habitat destruction, anti-predator campaigns, conflicts with livestock and general persecution by humans.

As grizzly bear and human populations increase in areas where bear populations are recovering, conservationists will need to reduce conflicts, especially when bears cause significant loss of livestock, or in towns and cities where they pose an immediate threat to human safety.

For the most recent and region-specific information on grizzly bear status and conservation in the U.S., see .

Fun Facts

1. Grizzly bears received their name because their brown fur can be tipped with white. This gives them a “grizzled” look, especially when backlit by the sun.

2. Grizzly bears can run fast, reaching speeds as fast as 35 miles an hour for very short sprints. They are good swimmers, too.

3. Grizzly bear cubs can climb trees to evade danger, but unlike black bears they lose this ability as their front claws grow longer.

Resources and More Information

, Grizzly Bear, 2025

, NWF blog, 2025

, NWF blog, 2022

For Kids:

, Ranger Rick, 2022

, Zoo Books

, Ranger Rick, 2013