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Temporal range: 38–0 
Late Eocene – Recent
Ours brun parcanimalierpyrenees 1.jpg
Brown bear (Ursus arctos)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Infraorder: Arctoidea
Parvorder: Ursida
Tedford, 1976
Family: Ursidae
G. Fischer de Waldheim, 1817
Type genus
Linnaeus, 1758



Spectacled Bears
Ursinae (All other bear species)

Bears are

caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, Europe, and Asia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade
paws with five nonretractile claws, and short tails.

While the

nocturnal and have an excellent sense of smell. Despite their heavy build and awkward gait, they are adept runners, climbers, and swimmers. Bears use shelters, such as caves and logs, as their dens; most species occupy their dens during the winter for a long period of hibernation
, up to 100 days.

Bears have been hunted since

in certain countries. The poaching and international trade of these most threatened populations are prohibited, but still ongoing.


The English word "bear" comes from

Proto-Indo-European word for "brown", so that "bear" would mean "the brown one".[1][2] However, Ringe notes that while this etymology is semantically plausible, a word meaning "brown" of this form cannot be found in Proto-Indo-European. He suggests instead that "bear" is from the Proto-Indo-European word *ǵʰwḗr- ~ *ǵʰwér "wild animal".[3] This terminology for the animal originated as a taboo avoidance term: proto-Germanic tribes replaced their original word for bear—arkto—with this euphemistic expression out of fear that speaking the animal's true name might cause it to appear.[4][5] According to author Ralph Keyes, this is the oldest known euphemism.[6]

Bear taxon names such as

Helarctos come from the ancient Greek ἄρκτος (arktos), meaning bear,[7] as do the names "arctic" and "antarctic", via the name of the constellation Ursa Major, the "Great Bear", prominent in the northern sky.[8]

Bear taxon names such as Ursidae and Ursus come from Latin Ursus/Ursa, he-bear/she-bear.

saint's name, means "little she-bear" (diminutive of Latin ursa). In Switzerland, the male first name "Urs" is especially popular, while the name of the canton and city of Bern is derived from Bär, German for bear. The Germanic name Bernard (including Bernhardt and similar forms) means "bear-brave", "bear-hardy", or "bold bear".[9][10] The Old English name Beowulf is a kenning, "bee-wolf", for bear, in turn meaning a brave warrior.[11]


The family Ursidae is one of nine families in the suborder Caniformia, or "doglike" carnivorans, within the order Carnivora. Bears' closest living relatives are the pinnipeds, canids, and musteloids.[12] Modern bears comprise eight species in three subfamilies: Ailuropodinae (monotypic with the giant panda), Tremarctinae (monotypic with the spectacled bear), and Ursinae (containing six species divided into one to three genera, depending on the authority). Nuclear chromosome analysis show that the karyotype of the six ursine bears is nearly identical, each having 74 chromosomes (see Ursid hybrid), whereas the giant panda has 42 chromosomes and the spectacled bear 52. These smaller numbers can be explained by the fusing of some chromosomes, and the banding patterns on these match those of the ursine species, but differ from those of procyonids, which supports the inclusion of these two species in Ursidae rather than in Procyonidae, where they had been placed by some earlier authorities.[13]


Plithocyon armagnacensis skull, a member of the extinct subfamily Hemicyoninae from the Miocene

The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including

Bering land bridge may have been possible during a major sea level low stand as early as the late Eocene (about 37 Mya) and continuing into the early Oligocene.[15] European genera morphologically very similar to Allocyon, and to the much younger American Kolponomos (about 18 Mya),[16] are known from the Oligocene, including Amphicticeps and Amphicynodon.[15] There has been various morphological evidence linking amphicynodontines with pinnipeds, as both groups were semi-aquatic, otter-like mammals.[17][18][19] In addition to the support of the pinniped–amphicynodontine clade, other morphological and some molecular evidence supports bears being the closest living relatives to pinnipeds.[20][21][22][18][23][19]

The raccoon-sized, dog-like Cephalogale is the oldest-known member of the subfamily Hemicyoninae, which first appeared during the middle Oligocene in Eurasia about 30 Mya.[15] The subfamily includes the younger genera Phoberocyon (20–15 Mya), and Plithocyon (15–7 Mya). A Cephalogale-like species gave rise to the genus Ursavus during the early Oligocene (30–28 Mya); this genus proliferated into many species in Asia and is ancestral to all living bears. Species of Ursavus subsequently entered North America, together with Amphicynodon and Cephalogale, during the early Miocene (21–18 Mya). Members of the living lineages of bears diverged from Ursavus between 15 and 20 Mya,[24][25] likely via the species Ursavus elmensis. Based on genetic and morphological data, the Ailuropodinae (pandas) were the first to diverge from other living bears about 19 Mya, although no fossils of this group have been found before about 11 Mya.[26][27]

The New World short-faced bears (Tremarctinae) differentiated from Ursinae following a dispersal event into North America during the mid-Miocene (about 13 Mya).[26] They invaded South America (≈2.5 or 1.2 Ma) following formation of the Isthmus of Panama.[28] Their earliest fossil representative is Plionarctos in North America (c. 10–2 Ma). This genus is probably the direct ancestor to the North American short-faced bears (genus Arctodus), the South American short-faced bears (Arctotherium), and the spectacled bears, Tremarctos, represented by both an extinct North American species (T. floridanus), and the lone surviving representative of the Tremarctinae, the South American spectacled bear (T. ornatus).[15]

in Europe

The subfamily Ursinae experienced a dramatic proliferation of taxa about 5.3–4.5 Mya, coincident with major environmental changes; the first members of the genus

Ursus appeared around this time. The sloth bear is a modern survivor of one of the earliest lineages to diverge during this radiation event (5.3 Mya); it took on its peculiar morphology, related to its diet of termites and ants, no later than by the early Pleistocene. By 3–4 Mya, the species Ursus minimus appears in the fossil record of Europe; apart from its size, it was nearly identical to today's Asian black bear. It is likely ancestral to all bears within Ursinae, perhaps aside from the sloth bear. Two lineages evolved from U. minimus: the black bears (including the sun bear, the Asian black bear, and the American black bear); and the brown bears (which includes the polar bear). Modern brown bears evolved from U. minimus via Ursus etruscus, which itself is ancestral to the extinct Pleistocene cave bear.[26] Species of Ursinae have migrated repeatedly into North America from Eurasia as early as 4 Mya during the early Pliocene.[29][30] The polar bear is the most recently evolved species and descended from a population of brown bears that became isolated in northern latitudes by glaciation 400,000 years ago.[31]


The relationship of the bear family with other carnivorans is shown in the following

molecular phylogenetic analysis of six genes in Flynn, 2005.[32]




African golden wolf



Brown bear

Common seal


Red panda

Striped skunk

Common raccoon

Steppe polecat

Note that although they are called "bears" in some languages, red pandas and raccoons and their close relatives are not bears, but rather musteloids.[32]

There are two phylogenetic hypotheses on the relationships among extant and fossil bear species. One is all species of bears are classified in seven subfamilies as adopted here and related articles:

Agriotheriinae, Ailuropodinae, Tremarctinae, and Ursinae.[33][34][35][36] Below is a cladogram of the subfamilies of bears after McLellan and Reiner (1992)[33] and Qiu et al. (2014):[36][clarification needed



Amphicynodontinae Kolponomos NT.jpg






Recherches pour servir à l'histoire naturelle des mammifères (Pl. 50) (white background).jpg

Spectacled bear (1829).jpg

Ursus arctos - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

The second alternative phylogenetic hypothesis was implemented by McKenna et al. (1997) to classify all the bear species into the superfamily Ursoidea, with Hemicyoninae and Agriotheriinae being classified in the family "Hemicyonidae".

Phocoidea.[37] In the McKenna and Bell classification both bears and pinnipeds are in a parvorder of carnivoran mammals known as Ursida, along with the extinct bear dogs of the family Amphicyonidae.[37] Below is the cladogram based on McKenna and Bell (1997) classification:[37][clarification needed



Daphoenodon superbus by R. B. Horsfall (coloured).png



Amphicynodontidae Kolponomos NT.jpg

Common seal








Recherches pour servir à l'histoire naturelle des mammifères (Pl. 50) (white background).jpg

Spectacled bear (1829).jpg

Ursus arctos - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

The phylogeny of extant bear species is shown in a cladogram based on complete mitochondrial DNA sequences from Yu et al. (2007)[38] The giant panda, followed by the spectacled bear, are clearly the oldest species. The relationships of the other species are not very well resolved, though the polar bear and the brown bear form a close grouping.[13]


Ursus arctos - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

Lossy-page1-2518px-Ursus maritimus - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

Ursus thibetanus - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam -(white background).jpg

Ursus americanus - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

Ursus malayanus - 1700-1880 - Print - Iconographia Zoologica - Special Collections University of Amsterdam - (white background).jpg

Tremarctos ornatus 1824 (flipped).jpg

Spectacled bear (1829).jpg

Recherches pour servir à l'histoire naturelle des mammifères (Pl. 50) (white background).jpg

Physical characteristics


Polar bear (left) and sun bear, the largest and smallest species respectively, on average

The bear family includes the most massive extant terrestrial members of the order Carnivora.

South American short-faced bears were the largest species known to have lived. The latter estimated to have weighed 1,600 kg (3,500 lb) and stood 3.4 m (11 ft 2 in) tall.[43][44] Body weight varies throughout the year in bears of temperate and arctic climates, as they build up fat reserves in the summer and autumn and lose weight during the winter.[45]


Unlike most other carnivorans, bears have plantigrade feet. Drawing by Richard Owen
, 1866.

Bears are generally bulky and robust animals with short tails. They are sexually dimorphic with regard to size, with males typically being larger.[46][47] Larger species tend to show increased levels of sexual dimorphism in comparison to smaller species.[47] Relying as they do on strength rather than speed, bears have relatively short limbs with thick bones to support their bulk. The shoulder blades and the pelvis are correspondingly massive. The limbs are much straighter than those of the big cats as there is no need for them to flex in the same way due to the differences in their gait. The strong forelimbs are used to catch prey, excavate dens, dig out burrowing animals, turn over rocks and logs to locate prey, and club large creatures.[45]

quadrupeds, bears can stand and sit as humans do, as demonstrated by this American black bear

Unlike most other land carnivorans, bears are plantigrade. They distribute their weight toward the hind feet, which makes them look lumbering when they walk. They are capable of bursts of speed but soon tire, and as a result mostly rely on ambush rather than the chase. Bears can stand on their hind feet and sit up straight with remarkable balance. Their front paws are flexible enough to grasp fruit and leaves. Bears' non-retractable claws are used for digging, climbing, tearing, and catching prey. The claws on the front feet are larger than those on the back and may be a hindrance when climbing trees; black bears are the most arboreal of the bears, and have the shortest claws. Pandas are unique in having a bony extension on the wrist of the front feet which acts as a thumb, and is used for gripping bamboo shoots as the animals feed.[45]

Most mammals have agouti hair, with each individual hair shaft having bands of color corresponding to two different types of melanin pigment. Bears however have a single type of melanin and the hairs have a single color throughout their length, apart from the tip which is sometimes a different shade. The coat consists of long guard hairs, which form a protective shaggy covering, and short dense hairs which form an insulating layer trapping air close to the skin. The shaggy coat helps maintain body heat during winter hibernation and is shed in the spring leaving a shorter summer coat. Polar bears have hollow, translucent guard hairs which gain heat from the sun and conduct it to the dark-colored skin below. They have a thick layer of blubber for extra insulation, and the soles of their feet have a dense pad of fur.[45] While bears tend to be uniform in color, some species may have markings on the chest or face and the giant panda has a bold black-and-white pelage.[48]

Bears have small rounded ears so as to minimize heat loss, but neither their hearing or sight are particularly acute. Unlike many other carnivorans they have

sense of smell, better than that of the dog, or possibly any other mammal. They use smell for signalling to each other (either to warn off rivals or detect mates) and for finding food. Smell is the principal sense used by bears to locate most of their food, and they have excellent memories which helps them to relocate places where they have found food before.[45]


amplify their vocalizations.[51]

Bears have a fairly simple digestive system typical for carnivorans, with a single stomach, short undifferentiated intestines and no cecum.[52][53] Even the herbivorous giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes. Its ability to digest cellulose is ascribed to the microbes in its gut.[54] Bears must spend much of their time feeding in order to gain enough nutrition from foliage. The panda, in particular, spends 12–15 hours a day feeding.[55]

Distribution and habitat

The spectacled bear is the only species found in South America.[56]

Extant bears are found in sixty countries primarily in the Northern Hemisphere and are concentrated in Asia, North America, and Europe. An exception is the spectacled bear; native to South America, it inhabits the Andean region.[56] The sun bear's range extends below the equator in Southeast Asia.[57] The Atlas bear, a subspecies of the brown bear was distributed in North Africa from Morocco to Libya, but it became extinct around the 1870s.[58]

The brown bear photographed near the Russian border in the forests of Kainuu, Finland

The most widespread species is the brown bear, which occurs from Western Europe eastwards through Asia to the western areas of North America. The American black bear is restricted to North America, and the polar bear is restricted to the Arctic Sea. All the remaining species of bear are Asian.[56] They occur in a range of habitats which include tropical lowland rainforest, both coniferous and broadleaf forests, prairies, steppes, montane grassland, alpine scree slopes, Arctic tundra and in the case of the polar bear, ice floes.[56][59] Bears may dig their dens in hillsides or use caves, hollow logs and dense vegetation for shelter.[59]

Behavior and ecology

Brown and American black bears are generally

olfaction to locate other foods, encounter mates, avoid rivals and recognize their cubs.[45]



Most bears are opportunistic

berries to insects, carrion, fresh meat, and fish, and have digestive systems and teeth adapted to such a diet.[56] At the extremes are the almost entirely herbivorous giant panda and the mostly carnivorous polar bear. However, all bears feed on any food source that becomes seasonally available.[55] For example, Asiatic black bears in Taiwan consume large numbers of acorns when these are most common, and switch to ungulates at other times of the year.[66]

When foraging for plants, bears choose to eat them at the stage when they are at their most nutritious and digestible, typically avoiding older

Bromeliads can make up to 50% of the diet of the spectacled bear, which also has strong jaws to bite them open.[74]

Brown bear feeding on infrequent, but predictable, salmon migrations in Alaska

The sloth bear is not as specialized as polar bears and the panda, has lost several front teeth usually seen in bears, and developed a long, suctioning tongue to feed on the ants, termites, and other burrowing insects. At certain times of the year, these insects can make up 90% of their diets.[75] Some individuals become addicted to sweets in garbage inside towns where tourism-related waste is generated throughout the year.[76] Some species may raid the nests of wasps and bees for the honey and immature insects, in spite of stinging from the adults.[77] Sun bears use their long tongues to lick up both insects and honey.[78] Fish are an important source of food for some species, and brown bears in particular gather in large numbers at salmon runs. Typically, a bear plunges into the water and seizes a fish with its jaws or front paws. The preferred parts to eat are the brain and eggs. Small burrowing mammals like rodents may be dug out and eaten.[79][67]

Polar bear feeding on a seal on an ice floe north of Svalbard
, Norway. It is the most carnivorous species.

The brown bear and both species of black bears sometimes take large ungulates, such as

bovids, mostly the young and weak.[66][80][79] These animals may be taken by a short rush and ambush, though hiding young may be stiffed out and pounced on.[67][81] The polar bear mainly preys on seals, stalking them from the ice or breaking into their dens. They primarily eat the highly digestible blubber.[82][79] Large mammalian prey is typically killed by a bite to the head or neck, or (in the case of young) simply pinned down and mauled.[67][83] Predatory behavior in bears is typically taught to the young by the mother.[79]

Bears are prolific

kleptoparasites, stealing food caches from rodents, and carcasses from other predators.[53][84] For hibernating species, weight gain is important as it provides nourishment during winter dormancy. A brown bear can eat 41 kg (90 lb) of food and gain 2–3 kg (4–7 lb) of fat a day prior to entering its den.[85]