brown bear

mammal, Ursus arctos
Also known as: Ursus arctos

brown bear, (Ursus arctos), shaggy-haired bear (family Ursidae) native to Europe, Asia, and northwestern North America. Numerous forms of the brown bear have been described; they are treated as several subspecies of Ursus arctos. One subspecies, the Kodiak bear (U. arctos middendorffi), weighs up to 720 kg (1,600 pounds) and is often considered to be the world’s largest carnivore, a title it shares with the polar bear (U. maritimus), which grows to a similar size. Although North American brown bears are traditionally called grizzlies, this common name refers formally to the subspecies U. arctos horribilis, which is widespread across northwestern North America (see grizzly bear).

Brown bears are omnivorous and feed on berries, plant roots and shoots, small mammals, fish, calves of many hoofed animals, and carrion. They often cache food in shallow holes, and they dig readily and vigorously in search of rodents. Except in some southern areas, bears retire to dens in winter; they accumulate large amounts of fat during late summer and autumn. Cubs, usually twins, are born in winter after about six to eight months of gestation. At birth a cub weighs less than 1 kg (2.2 pounds).

Eurasian brown bears are generally solitary animals that are able to run and swim well. They are usually 120–210 cm (about 48–83 inches) long and weigh 135–250 kg (300–550 pounds); the exceptionally large Siberian brown bear (U. arctos beringianus), weighing as much as 360 kg (800 pounds), approximates the size of the North American grizzly. Coat colour is highly variable, ranging from grayish white through bluish and brownish shades to almost black. Eurasian brown bears are commonly seen in zoos; formerly they were often trained to move rhythmically to music—the so-called dancing bears of European carnivals and festivals. They once roamed most of Europe and Asia; however, the animal’s southern range has been significantly reduced.

Mute swan with cygnet. (birds)
Britannica Quiz
Match the Baby Animal to Its Mama Quiz

Brown bears have an extremely large geographic distribution, and their worldwide population totals more than 200,000 individuals. For these reasons, the International Union for Conservation of Nature (IUCN) Red List of Threatened Species has classified the brown bear as a species of least concern. Brown bears living in close proximity to humans are often regarded as pests because of the animals’ attraction to human foods. Their large size and relatively aggressive disposition can unsettle people who come in contact with them, and brown bears that frequent human settlements are sometimes killed by landowners and government officials. Other sources of brown bear mortality include collisions with trains and automobiles, poaching, and sport hunting. In addition, the gallbladder and bile of some brown bears are harvested to make traditional medicines that purportedly alleviate digestive problems and inflammation and purify the blood. Many harvesting operations also remove and sell the animals’ paws, which are considered a delicacy in parts of Asia. The Ainu people of Japan worship the brown bear as a god of the mountains, and some mountain-dwelling Ainu consider the bear their ancestor.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by John P. Rafferty.
Top Questions

How many species of bears are there?

What do bears eat?

Which type of bear is the largest?

How long do bears live?

News

Caleb Williams, family tried to keep Bears from drafting QB No. 1 overall, per reports May 16, 2025, 7:06 AM ET (USA Today)

bear, (family Ursidae), any of eight species of large short-tailed carnivores found in the Americas, Europe, and Asia. The sun bear (Helarctos malayanus) is the smallest, often weighing less than 50 kg (110 pounds). The largest bear is either the Kodiak bear (Ursus arctos middendorffi, a subspecies of Alaskan brown bear; see also grizzly bear) or the polar bear (Ursus maritimus), depending upon which measurements are considered; either of these bears can weigh up to 720 kg (1,600 pounds). The black bear (Ursus americanus) is common in parts of the United States and Canada.

Bears are generally omnivorous, but dietary preferences range from seals for the entirely carnivorous polar bear to assorted vegetation for the largely herbivorous spectacled bear (Tremarctos ornatus). The giant panda (Ailuropoda melanoleuca) eats only bamboo. Usually gaining weight beforehand, most bears sleep fitfully through much of the winter, but they do not truly hibernate. Despite their bulk, most bears climb with ease and swim strongly.

Natural history

Ursids are mainly animals of northern temperate regions and are found farther north than any other mammal. The Arctic fox is found as far north on land, but the polar bear regularly roams on sea ice hundreds of kilometres from shore. Africa and Australia lack bears entirely. The spectacled bear of South America’s Andes Mountains is the only bear species that lives south of the Equator.

Although clumsy in appearance, bears can move surprisingly fast, even through dense cover that would seriously impede a human or a horse. Their senses of sight and hearing, however, are poorly developed, and most hunting is done by smell. Some, such as black bears and spectacled bears, are strong climbers, and all are strong swimmers, most notably the polar bear. Bears do not generally communicate by sound and usually are quiet, but they do growl at times when feeding, when being challenged by another bear or by humans, and when competing for mates.

Except for the carnivorous polar bear and the vegetarian giant panda, ursids are omnivorous, consuming many items that seem small for an animal of such large size. Ants, bees, seeds of trees, roots, nuts, berries, insect larvae such as grubs, and even the dainty dogtooth violet are eaten. Many bears relish honey, and the sun bear is sometimes called the “honey bear” because of this. Prey taken by bears includes rodents, fish, deer, pigs, and seals. Grizzlies (a North American subspecies of the brown bear, Ursus arctos) are known for their skillful fishing during the spawning runs of salmon. The polar bear’s diet is dictated by the Arctic environment, as little vegetation grows within its range. The Asian sloth bear (Melursus ursinus) delights especially in raiding and destroying termite nests, sucking up termites and larvae with its funnel-like lips. The giant panda has a special bone formation of the forefoot that functions as a sixth digit; it is opposable to the other five and thus is useful in handling bamboo.

Lion (panthera leo)
Britannica Quiz
Deadliest Animals Quiz

Most bears, including the American and Asiatic black bears (Ursus americanus and U. thibetanus), eat large amounts of food before entering a den for a period of deep sleep during the winter. The polar bear digs a den in the snow, whereas grizzlies build large mounds of dirt in front of their dens. Bears, however, lack the physiological characteristics (lower heart rate, body temperature, breathing rate, and blood pressure) exhibited by animals that truly hibernate.

Male polar bears sometimes congregate, but otherwise bears are solitary except during the mating season. Then they tend to congregate, pair off, and mate in seclusion. The male leaves the female soon after mating and plays no role in raising the young. Gestation periods vary, the fertilized egg remaining dormant in the uterus (delayed implantation), which ensures the birth of young while the female is in the winter den and guarantees that the cubs will emerge from the den in the spring, when food is abundant. Ursids breed once per year at most, and many bears breed only every two to four years. The breeding season is usually in late spring or early summer. Delayed implantation results in most births occurring in January or February. Newborn bears weigh about half a kilogram (one pound) and are about 23 cm (9 inches) long from the nose to the tip of the short tail. Twins are most common in bears, but up to five young may be produced. The cubs nurse for a few months and stay with the female until the next breeding (about a year and a half or more after birth). Most young, however, can get along on their own by about six months of age. Bears reach breeding condition at three and a half to six years of age, males usually maturing later than females. Longevity of bears in the wild ranges from 15 to 30 years, but in captivity they can live considerably longer.

Are you a student?
Get a special academic rate on Britannica Premium.

Because of their large size, bears have few natural enemies in the wild. Most mortality occurs because of hunting by humans. On occasion, bears that fail to accumulate enough fat to last throughout the winter may die of starvation. Young bears are more vulnerable to predation because of their smaller size and thus may be killed by other carnivores such as wolves or cougars but most importantly by other bears, especially males. For this reason, females with cubs are highly protective of their young in the vicinity of males.

Home ranges occupied by individual bears vary in size depending on the abundance of food, and larger areas are used when food is in short supply. Although highly variable among geographic areas and even among seasons, American black bears roam areas of 40 to 200 square km (15 to 77 square miles), grizzlies about 300 to 700 square km (115 to 270 square miles). Some polar bears trek across ranges of more than 125,000 square km (48,000 square miles).