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Bears are
carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...
n
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s of the family Ursidae. They are classified as 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 151px, Portion of a human skeleton, showing plantigrade habit In terrestrial animals, plantigrade locomotion means walking with the toes and metatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrial mammals. T ...
paws with five nonretractile claws, and short tails. While the
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
is mostly
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...
, and the
giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear (or simply the panda), is a bear species endemic to China. It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes us ...
feeds almost entirely on bamboo, the remaining six species are omnivorous with varied diets. With the exception of courting individuals and mothers with their young, bears are typically solitary animals. They may be diurnal or
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
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 Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
, up to 100 days. Bears have been hunted since
prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of ...
times for their meat and fur; they have been used for bear-baiting and other forms of entertainment, such as being made to dance. With their powerful physical presence, they play a prominent role in the arts, mythology, and other cultural aspects of various human societies. In modern times, bears have come under pressure through encroachment on their habitats and illegal trade in bear parts, including the Asian
bile bear Bile bears, sometimes called battery bears, are bears kept in captivity to harvest their bile, a digestive fluid produced by the liver and stored in the gallbladder, which is used by some traditional Asian medicine practitioners. It is estimated ...
market. The
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
lists six bear species as
vulnerable Vulnerable may refer to: General * Vulnerability * Vulnerability (computing) * Vulnerable adult * Vulnerable species Music Albums * ''Vulnerable'' (Marvin Gaye album), 1997 * ''Vulnerable'' (Tricky album), 2003 * ''Vulnerable'' (The Used album) ...
or endangered, and even least concern species, such as the brown bear, are at risk of extirpation in certain countries. The poaching and international trade of these most threatened populations are prohibited, but still ongoing.


Etymology

The English word "bear" comes from
Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...
' and belongs to a family of names for the bear in Germanic languages, such as Swedish ', also used as a first name. This form is conventionally said to be related to a Proto-Indo-European word for "brown", so that "bear" would mean "the brown one". 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". 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. According to author Ralph Keyes, this is the oldest known
euphemism A euphemism () is an innocuous word or expression used in place of one that is deemed offensive or suggests something unpleasant. Some euphemisms are intended to amuse, while others use bland, inoffensive terms for concepts that the user wishes ...
. Bear taxon names such as Arctoidea and '' Helarctos'' come from the ancient Greek ἄρκτος (''arktos''), meaning bear, as do the names " arctic" and "
antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...
", via the name of the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...
Ursa Major, the "Great Bear", prominent in the northern sky. Bear taxon names such as Ursidae and ''Ursus'' come from Latin ''Ursus/Ursa'', he-bear/she-bear. The female first name " Ursula", originally derived from a Christian
saint In religious belief, a saint is a person who is recognized as having an exceptional degree of Q-D-Š, holiness, likeness, or closeness to God. However, the use of the term ''saint'' depends on the context and Christian denomination, denominat ...
'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 german: Berner(in)french: Bernois(e) it, bernese , neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen , website ...
is derived from ''Bär'', German for bear. The Germanic name Bernard (including Bernhardt and similar forms) means "bear-brave", "bear-hardy", or "bold bear". The Old English name
Beowulf ''Beowulf'' (; ang, Bēowulf ) is an Old English epic poem in the tradition of Germanic heroic legend consisting of 3,182 alliterative lines. It is one of the most important and most often translated works of Old English literature. The ...
is a kenning, "bee-wolf", for bear, in turn meaning a brave warrior.


Taxonomy

The family Ursidae is one of nine families in the suborder
Caniformia Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs (wolves, foxes, etc.), bears, raccoons, and mustelids. The Pinnipedia (seals, walruses and sea lions) are also assigned to this group. ...
, or "doglike" carnivorans, within the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...
. Bears' closest living relatives are the pinnipeds, canids, and musteloids. Modern bears comprise eight species in three subfamilies: Ailuropodinae (monotypic with the
giant panda The giant panda (''Ailuropoda melanoleuca''), also known as the panda bear (or simply the panda), is a bear species endemic to China. It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes us ...
), 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 A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...
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 Procyonidae is a New World family of the order Carnivora. It comprises the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous. Character ...
, where they had been placed by some earlier authorities.


Evolution

The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including '' Parictis'' (late Eocene to early middle Miocene, 38–18 
Mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * Burmese ...
) and the slightly younger ''Allocyon'' (early
Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
, 34–30 Mya), both from North America. These animals looked very different from today's bears, being small and raccoon-like in overall appearance, with diets perhaps more similar to that of a badger. ''Parictis'' does not appear in Eurasia and Africa until the Miocene. It is unclear whether late-Eocene ursids were also present in Eurasia, although faunal exchange across the 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. European genera morphologically very similar to ''Allocyon'', and to the much younger American '' Kolponomos'' (about 18 Mya), are known from the Oligocene, including ''Amphicticeps'' and '' Amphicynodon''. There has been various morphological evidence linking amphicynodontines with pinnipeds, as both groups were semi-aquatic, otter-like mammals. 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. 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. The subfamily includes the younger genera ''
Phoberocyon ''Phoberocyon'' is a large extinct genus of hemicyonine bear, found primarily in North America during the Miocene. It lived from 28.4 to 13.7 mya, existing for approximately . One species, ''P. hispanicus'', is known from Miocene Spain , im ...
'' (20–15 Mya), and ''
Plithocyon ''Plithocyon'' is an extinct genus of hemicyonine bear of the Miocene epoch, endemic to North America and Europe. It lived from ~15.97—11.61 Ma, existing for approximately . Fossil distribution Sites and age of some specimens: *Hemicyon Qua ...
'' (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, 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. The New World short-faced bears (Tremarctinae) differentiated from Ursinae following a dispersal event into North America during the mid-Miocene (about 13 Mya). They invaded South America (≈2.5 or 1.2 Ma) following formation of the
Isthmus of Panama The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...
. 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''). 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 Ursus is Latin for bear. It may also refer to: Animals * ''Ursus'' (mammal), a genus of bears People * Ursus of Aosta, 6th-century evangelist * Ursus of Auxerre, 6th-century bishop * Ursus of Solothurn, 3rd-century martyr * Ursus (''praefectus ...
'' 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 The Asian black bear (''Ursus thibetanus''), also known as the Asiatic black bear, moon bear and white-chested bear, is a medium-sized bear species native to Asia that is largely adapted to an arboreal lifestyle. It lives in the Himalayas, sout ...
. 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 The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...
); and the brown bears (which includes the
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
). Modern brown bears evolved from ''U. minimus'' via '' Ursus etruscus'', which itself is ancestral to the extinct Pleistocene cave bear. Species of Ursinae have migrated repeatedly into North America from Eurasia as early as 4 Mya during the early Pliocene. 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.


Phylogeny

The relationship of the bear family with other carnivorans is shown in the following
phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
, which is based on the molecular phylogenetic analysis of six genes in Flynn, 2005. Note that although they are called "bears" in some languages, red pandas and raccoons and their close relatives are not bears, but rather musteloids. 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: Amphicynodontinae, Hemicyoninae, Ursavinae,
Agriotheriinae ''Agriotherium'' is an extinct genus of bears whose fossils are found in Miocene through Pleistocene-aged strata of North America, Europe, Africa, and Asia. This long-lived genus persisted from at least ~11.6–2.5 Mya. Materials from the late-s ...
, Ailuropodinae, Tremarctinae, and Ursinae. Below is a cladogram of the subfamilies of bears after McLellan and Reiner (1992) and Qiu ''et al''. (2014): 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". Amphicynodontinae under this classification were classified as stem- pinnipeds in the superfamily
Phocoidea The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae (). They are sometimes called crawling seals to distinguish them from th ...
. In the McKenna and Bell classification both bears and pinnipeds are in a parvorder of
carnivora Carnivora is a Clade, monophyletic order of Placentalia, placental mammals consisting of the most recent common ancestor of all felidae, cat-like and canidae, dog-like animals, and all descendants of that ancestor. Members of this group are f ...
n mammals known as Ursida, along with the extinct bear dogs of the family Amphicyonidae. Below is the cladogram based on McKenna and Bell (1997) classification: The phylogeny of extant bear species is shown in a cladogram based on complete
mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...
sequences from Yu ''et al''. (2007) 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.


Physical characteristics


Size

The bear family includes the most massive extant terrestrial members of the order Carnivora. The polar bear is considered to be the largest extant species, with adult males weighing and measuring in total length. The smallest species is the sun bear, which ranges in weight and in length. Prehistoric North and
South American short-faced bear ''Arctotherium'' ("''bear beast''") is an extinct genus of the Pleistocene short-faced bears endemic to Central and South America. ''Arctotherium'' migrated from North America to South America during the Great American Interchange, following the f ...
s were the largest species known to have lived. The latter estimated to have weighed and stood tall. 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.


Morphology

Bears are generally bulky and robust animals with short tails. They are sexually dimorphic with regard to size, with males typically being larger. Larger species tend to show increased levels of sexual dimorphism in comparison to smaller species. Relying as they do on strength rather than speed, bears have relatively short limbs with thick bones to support their bulk. The
shoulder blades The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either ...
and the
pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...
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, to excavate dens, to dig out burrowing animals, to turn over rocks and logs to locate prey, and to club large creatures. Unlike most other land carnivorans, bears are
plantigrade 151px, Portion of a human skeleton, showing plantigrade habit In terrestrial animals, plantigrade locomotion means walking with the toes and metatarsals flat on the ground. It is one of three forms of locomotion adopted by terrestrial mammals. T ...
. 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. 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. 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. 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
color vision Color vision, a feature of visual perception, is an ability to perceive differences between light composed of different wavelengths (i.e., different spectral power distributions) independently of light intensity. Color perception is a part of ...
, perhaps to help them distinguish ripe nuts and fruits. They are unique among carnivorans in not having touch-sensitive whiskers on the muzzle; however, they have an excellent 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. The skulls of bears are massive, providing anchorage for the powerful masseter and temporal jaw muscles. The canine teeth are large but mostly used for display, and the molar teeth flat and crushing. Unlike most other members of the Carnivora, bears have relatively undeveloped carnassial teeth, and their teeth are adapted for a diet that includes a significant amount of vegetable matter. Considerable variation occurs in dental formula even within a given species. This may indicate bears are still in the process of evolving from a mainly meat-eating diet to a predominantly herbivorous one. Polar bears appear to have secondarily re-evolved carnassial-like cheek teeth, as their diets have switched back towards carnivory. Sloth bears lack lower central incisors and use their protrusible lips for sucking up the termites on which they feed. The general dental formula for living bears is: . The structure of the
larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...
of bears appears to be the most
basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...
of the caniforms. They possess air pouches connected to the pharynx which may amplify their vocalizations. Bears have a fairly simple digestive system typical for carnivorans, with a single stomach, short undifferentiated intestines and no cecum. 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. 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.


Distribution and habitat

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. The sun bear's range extends below the equator in Southeast Asia. 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. 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 The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...
is restricted to North America, and the
polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...
is restricted to the Arctic Sea. All the remaining species of bear are Asian. 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. Bears may dig their dens in hillsides or use caves, hollow logs and dense vegetation for shelter.


Behavior and ecology

Brown and American black bears are generally diurnal, meaning that they are active for the most part during the day, though they may forage substantially by night. Other species may be
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
, active at night, though female sloth bears with cubs may feed more at daytime to avoid competition from conspecifics and nocturnal predators. Bears are overwhelmingly solitary and are considered to be the most asocial of all the Carnivora. The only times bears are encountered in groups are mothers with young or occasional seasonal bounties of rich food (such as salmon runs). Fights between males can occur and older individuals may have extensive scarring, which suggests that maintaining dominance can be intense. With their acute sense of smell, bears can locate carcasses from several kilometres away. They use
olfaction The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it ...
to locate other foods, encounter mates, avoid rivals and recognize their cubs.


Feeding

Most bears are opportunistic
omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
s and consume more plant than animal matter, and appears to have evolved from an ancestor which was a low-protein macronutrient omnivore. They eat anything from leaves, roots, and berries to insects,
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...
, fresh meat, and fish, and have digestive systems and teeth adapted to such a diet. 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. For example, Asiatic black bears in Taiwan consume large numbers of
acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera ''Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and borne ...
s when these are most common, and switch to ungulates at other times of the year. When foraging for plants, bears choose to eat them at the stage when they are at their most nutritious and digestible, typically avoiding older grasses, sedges and leaves. Hence, in more northern temperate areas, browsing and grazing is more common early in spring and later becomes more restricted. Knowing when plants are ripe for eating is a learned behavior. Berries may be foraged in bushes or at the tops of trees, and bears try to maximize the number of berries consumed versus foliage. In autumn, some bear species forage large amounts of naturally fermented fruits, which affects their behavior. Smaller bears climb trees to obtain
mast Mast, MAST or MASt may refer to: Engineering * Mast (sailing), a vertical spar on a sailing ship * Flagmast, a pole for flying a flag * Guyed mast, a structure supported by guy-wires * Mooring mast, a structure for docking an airship * Radio mast ...
(edible reproductive parts, such as acorns). Such masts can be very important to the diets of these species, and mast failures may result in long-range movements by bears looking for alternative food sources. Brown bears, with their powerful digging abilities, commonly eat roots. The panda's diet is over 99% bamboo, of 30 different species. Its strong jaws are adapted for crushing the tough stems of these plants, though they prefer to eat the more nutritious leaves.
Bromeliad The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
s can make up to 50% of the diet of the spectacled bear, which also has strong jaws to bite them open. 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. Some individuals become addicted to sweets in garbage inside towns where tourism-related waste is generated throughout the year. Some species may raid the nests of wasps and
bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...
s for the
honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
and immature insects, in spite of stinging from the adults. Sun bears use their long tongues to lick up both insects and honey. 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. The brown bear and both species of black bears sometimes take large ungulates, such as deer and bovids, mostly the young and weak. These animals may be taken by a short rush and ambush, though hiding young may be stiffed out and pounced on. The polar bear mainly preys on seals, stalking them from the ice or breaking into their dens. They primarily eat the highly digestible blubber. 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. Predatory behavior in bears is typically taught to the young by the mother. Bears are prolific
scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...
s and kleptoparasites, stealing food caches from rodents, and carcasses from other predators. For hibernating species, weight gain is important as it provides nourishment during winter dormancy. A brown bear can eat of food and gain of fat a day prior to entering its den.


Communication

Bears produce a number of vocal and non-vocal sounds. Tongue-clicking, grunting or chuffing many be made in cordial situations, such as between mothers and cubs or courting couples, while moaning, huffing, snorting or blowing air is made when an individual is stressed. Barking is produced during times of alarm, excitement or to give away the animal's position. Warning sounds include jaw-clicking and lip-popping, while teeth-chatters, bellows, growls, roars and pulsing sounds are made in aggressive encounters. Cubs may squeal, bawl, bleat or scream when in distress and make motor-like humming when comfortable or nursing. Bears sometimes communicate with visual displays such as standing upright, which exaggerates the individual's size. The chest markings of some species may add to this intimidating display. Staring is an aggressive act and the facial markings of spectacled bears and giant pandas may help draw attention to the eyes during
agonistic An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agoni ...
encounters. Individuals may approach each other by stiff-legged walking with the head lowered. Dominance between bears is asserted by making a frontal orientation, showing the canine teeth, muzzle twisting and neck stretching. A subordinate may respond with a lateral orientation, by turning away and dropping the head and by sitting or lying down. Bears may mark territory by rubbing against trees and other objects which may serve to spread their scent. This is usually accompanied by clawing and biting the object. Bark may be spread around to draw attention to the marking post. Pandas are known to mark objects with urine and a waxy substance from their anal glands. Polar bears leave behind their scent in their tracks which allow individuals to keep track of one another in the vast Arctic wilderness.


Reproduction and development

The mating system of bears has variously been described as a form of polygyny,
promiscuity Promiscuity is the practice of engaging in sexual activity frequently with different Sexual partner, partners or being indiscriminate in the choice of sexual partners. The term can carry a moral judgment. A common example of behavior viewed as pro ...
and serial monogamy. During the breeding season, males take notice of females in their vicinity and females become more tolerant of males. A male bear may visit a female continuously over a period of several days or weeks, depending on the species, to test her reproductive state. During this time period, males try to prevent rivals from interacting with their mate. Courtship may be brief, although in some Asian species, courting pairs may engage in wrestling, hugging, mock fighting and vocalizing. Ovulation is induced by mating, which can last up to 30 minutes depending on the species.
Gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...
typically lasts 6–9 months, including
delayed implantation Embryonic diapause (from late 19th century English: dia- ‘through’ + pause- 'delay') (aka delayed implantation in mammals) is an evolutionary reproductive strategy used by several animal species across a number of kingdoms, including approximate ...
, and litter size numbers up to four cubs. Giant pandas may give birth to twins but they can only suckle one young and the other is left to die. In northern living species, birth takes place during winter dormancy. Cubs are born blind and helpless with at most a thin layer of hair, relying on their mother for warmth. The milk of the female bear is rich in fat and antibodies and cubs may suckle for up to a year after they are born. By 2–3 months, cubs can follow their mother outside the den. They usually follow her on foot, but sloth bear cubs may ride on their mother's back. Male bears play no role in raising young.
Infanticide Infanticide (or infant homicide) is the intentional killing of infants or offspring. Infanticide was a widespread practice throughout human history that was mainly used to dispose of unwanted children, its main purpose is the prevention of reso ...
, where an adult male kills the cubs of another, has been recorded in polar bears, brown bears and American black bears but not in other species. Males kill young to bring the female into estrus. Cubs may flee and the mother defends them even at the cost of her life. In some species, offspring may become independent around the next spring, though some may stay until the female successfully mates again. Bears reach sexual maturity shortly after they disperse; at around 3–6 years depending on the species. Male Alaskan brown bears and polar bears may continue to grow until they are 11 years old. Lifespan may also vary between species. The brown bear can live an average of 25 years.


Hibernation

Bears of northern regions, including the
American black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...
and the
grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...
, hibernate in the winter. During hibernation, the bear's metabolism slows down, its body temperature decreases slightly, and its heart rate slows from a normal value of 55 to just 9 beats per minute. Bears normally do not wake during their hibernation, and can go the entire period without eating, drinking, urinating, or defecating. A fecal plug is formed in the colon, and is expelled when the bear wakes in the spring. If they have stored enough body fat, their muscles remain in good condition, and their protein maintenance requirements are met from recycling waste urea. Female bears give birth during the hibernation period, and are roused when doing so.


Mortality

Bears do not have many predators. The most important are humans, and as they started cultivating crops, they increasingly came in conflict with the bears that raided them. Since the invention of firearms, people have been able to kill bears with greater ease. Felids like the tiger may also prey on bears, particularly cubs, which may also be threatened by canids. Bears are parasitized by eighty species of parasites, including single-celled protozoans and gastro-intestinal worms, and nematodes and flukes in their heart, liver, lungs and bloodstream. Externally they have ticks, fleas and lice. A study of American black bears found seventeen species of endoparasite including the protozoan '' Sarcocystis'', the parasitic worm '' Diphyllobothrium mansonoides'', and the nematodes '' Dirofilaria immitis'', '' Capillaria aerophila'', ''
Physaloptera Systematics ''Physaloptera'' is a genus of parasitic nematodes in the family Physalopteridae. Species include: *''Physaloptera dilatata''Muniz-Pereira et al., 2009, p. 11 *''Physaloptera dispar'' *''Physaloptera hispida''Kinsella, 1974, p ...
'' sp., ''
Strongyloides ''Strongyloides'' (from Greek ''strongylos'', round, + ''eidos'', resemblance), anguillula, or threadworm is a genus of small nematode parasites, belonging to the family Strongylidae, commonly found in the small intestine of mammals (particularl ...
'' sp. and others. Of these, ''D. mansonoides'' and adult ''C. aerophila'' were causing pathological symptoms. By contrast, polar bears have few parasites; many parasitic species need a secondary, usually terrestrial, host, and the polar bear's life style is such that few alternative hosts exist in their environment. The protozoan '' Toxoplasma gondii'' has been found in polar bears, and the nematode '' Trichinella nativa'' can cause a serious infection and decline in older polar bears. Bears in North America are sometimes infected by a '' Morbillivirus'' similar to the canine distemper virus. They are susceptible to infectious canine hepatitis (CAV-1), with free-living black bears dying rapidly of encephalitis and hepatitis.


Relationship with humans


Conservation

In modern times, bears have come under pressure through encroachment on their habitats and illegal trade in bear parts, including the Asian
bile bear Bile bears, sometimes called battery bears, are bears kept in captivity to harvest their bile, a digestive fluid produced by the liver and stored in the gallbladder, which is used by some traditional Asian medicine practitioners. It is estimated ...
market, though hunting is now banned, largely replaced by farming. The
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
lists six bear species as
vulnerable Vulnerable may refer to: General * Vulnerability * Vulnerability (computing) * Vulnerable adult * Vulnerable species Music Albums * ''Vulnerable'' (Marvin Gaye album), 1997 * ''Vulnerable'' (Tricky album), 2003 * ''Vulnerable'' (The Used album) ...
; even the two least concern species, the brown bear and the American black bear, are at risk of extirpation in certain areas. In general these two species inhabit remote areas with little interaction with humans, and the main non-natural causes of mortality are hunting, trapping, road-kill and depredation. Laws have been passed in many areas of the world to protect bears from habitat destruction. Public perception of bears is often positive, as people identify with bears due to their omnivorous diets, their ability to stand on two legs, and their symbolic importance. Support for bear protection is widespread, at least in more affluent societies. The giant panda has become a worldwide symbol of conservation. The
Sichuan Giant Panda Sanctuaries The Sichuan Giant Panda Sanctuaries () located in southwest Sichuan province of China, is the home to more than 30% of the world's giant pandas and is among the most important sites for the captive breeding of these pandas. It covers 9245 km2 ...
, which are home to around 30% of the wild panda population, gained a UNESCO World Heritage Site designation in 2006. Where bears raid crops or attack livestock, they may come into conflict with humans. In poorer rural regions, attitudes may be more shaped by the dangers posed by bears, and the economic costs they cause to farmers and ranchers.


Attacks

Several bear species are dangerous to humans, especially in areas where they have become used to people; elsewhere, they generally avoid humans. Injuries caused by bears are rare, but are widely reported. Bears may attack humans in response to being startled, in defense of young or food, or even for predatory reasons.


Entertainment, hunting, food and folk medicine

Bears in captivity have for centuries been used for entertainment. They have been trained to
dance Dance is a performing art form consisting of sequences of movement, either improvised or purposefully selected. This movement has aesthetic and often symbolic value. Dance can be categorized and described by its choreography, by its repertoir ...
, and were kept for baiting in Europe at least since the 16th century. There were five bear-baiting gardens in
Southwark Southwark ( ) is a district of Central London situated on the south bank of the River Thames, forming the north-western part of the wider modern London Borough of Southwark. The district, which is the oldest part of South London, developed ...
, London, at that time; archaeological remains of three of these have survived. Across Europe, nomadic
Romani Romani may refer to: Ethnicities * Romani people, an ethnic group of Northern Indian origin, living dispersed in Europe, the Americas and Asia ** Romani genocide, under Nazi rule * Romani language, any of several Indo-Aryan languages of the Roma ...
bear handlers called Ursari lived by busking with their bears from the 12th century. Bears have been hunted for sport, food, and folk medicine. Their meat is dark and stringy, like a tough cut of beef. In
Cantonese cuisine Cantonese or Guangdong cuisine, also known as Yue cuisine ( or ) is the cuisine of Guangdong province of China, particularly the provincial capital Guangzhou, and the surrounding regions in the Pearl River Delta including Hong Kong and Maca ...
, bear paws are considered a delicacy. Bear meat should be cooked thoroughly, as it can be infected with the parasite '' Trichinella spiralis''. The peoples of eastern Asia use bears' body parts and secretions (notably their gallbladders and bile) as part of traditional Chinese medicine. More than 12,000 bears are thought to be kept on farms in China, Vietnam, and South Korea for the production of bile. Trade in bear products is prohibited under CITES, but bear bile has been detected in shampoos, wine and herbal medicines sold in Canada, the United States and Australia. File:The dancing bear by William Frederick Witherington.jpg, ''The Dancing Bear'' by
William Frederick Witherington William Frederick Witherington (26 May 1785 – 10 April 1865) was an English painter and academic. Born in London, he entered the Royal Academy Schools in 1805. Except for one year he exhibited annually at the Royal Academy from 1811 until his ...
, 1822 File:Theodor Aman - Ursarul.jpg, A nomadic '' ursar'', a
Romani Romani may refer to: Ethnicities * Romani people, an ethnic group of Northern Indian origin, living dispersed in Europe, the Americas and Asia ** Romani genocide, under Nazi rule * Romani language, any of several Indo-Aryan languages of the Roma ...
bear-busker. Drawing by Theodor Aman, 1888


Cultural depictions

Bears have been popular subjects in art, literature, folklore and mythology. The image of the mother bear was prevalent throughout societies in North America and Eurasia, based on the female's devotion and protection of her cubs. In many Native American cultures, the bear is a symbol of rebirth because of its hibernation and re-emergence. A widespread belief among cultures of North America and northern Asia associated bears with shaman; this may be based on the solitary nature of both. Bears have thus been thought to predict the future and shaman were believed to have been capable of transforming into bears. There is evidence of prehistoric
bear worship Bear worship (also known as the bear cult or arctolatry) is the religious practice of the worshipping of bears found in many North Eurasian ethnic religions such as among the Sami, Nivkh, Ainu, Basques, Germanic peoples, Slavs and Finns. There a ...
, though this is disputed by archaeologists. It is possible that bear worship existed in early Chinese and Ainu cultures. The prehistoric Finns,
Siberian peoples Siberia, including the Russian Far East, is a vast region spanning the North Asia, northern part of the Asian continent, and forming the Asiatic portion of Russia. As a result of the Russian conquest of Siberia (17th to 19th centuries) and of t ...
and more recently Koreans considered the bear as the spirit of their forefathers. Artio (''Dea Artio'' in the
Gallo-Roman religion Gallo-Roman religion is a fusion of the traditional religious practices of the Gauls, who were originally Celtic speakers, and the Roman and Hellenistic religions introduced to the region under Roman Imperial rule. It was the result of selective ...
) was a
Celtic Celtic, Celtics or Keltic may refer to: Language and ethnicity *pertaining to Celts, a collection of Indo-European peoples in Europe and Anatolia **Celts (modern) *Celtic languages **Proto-Celtic language * Celtic music *Celtic nations Sports Fo ...
bear goddess. Evidence of her worship has notably been found at
Bern german: Berner(in)french: Bernois(e) it, bernese , neighboring_municipalities = Bremgarten bei Bern, Frauenkappelen, Ittigen, Kirchlindach, Köniz, Mühleberg, Muri bei Bern, Neuenegg, Ostermundigen, Wohlen bei Bern, Zollikofen , website ...
, itself named for the bear. Her name is derived from the Celtic word for "bear", ''artos''. In ancient Greece, the archaic cult of Artemis in bear form survived into Classical times at Brauron, where young Athenian girls passed an initiation rite as ''arktoi'' "she bears". The constellations of Ursa Major and Ursa Minor, the great and little bears, are named for their supposed resemblance to bears, from the time of Ptolemy. The nearby star Arcturus means "guardian of the bear", as if it were watching the two constellations. Ursa Major has been associated with a bear for as much as 13,000 years since
Paleolithic The Paleolithic or Palaeolithic (), also called the Old Stone Age (from Greek: παλαιός ''palaios'', "old" and λίθος ''lithos'', "stone"), is a period in human prehistory that is distinguished by the original development of stone too ...
times, in the widespread
Cosmic Hunt The Cosmic Hunt is an old and widely distributed family of cognate myths. They are stories about a large animal that is pursued by hunters, is wounded, and is transformed into a constellation. Variants of the Cosmic Hunt are common in cultures of ...
myths. These are found on both sides of the Bering land bridge, which was lost to the sea some 11,000 years ago. Bears are popular in children's stories, including Winnie the Pooh, Paddington Bear, Gentle Ben and "
The Brown Bear of Norway The Brown Bear of Norway is an Irish fairy tale collected by Patrick Kennedy which appeared in his ''Legendary Fictions of the Irish Celts'' (1866). It was later included by Andrew Lang in his anthology '' The Lilac Fairy Book'' (1910), though La ...
". An early version of " Goldilocks and the Three Bears", was published as "The Three Bears" in 1837 by Robert Southey, many times retold, and illustrated in 1918 by Arthur Rackham. The
Hanna-Barbera Hanna-Barbera Cartoons, Inc. ( ) was an American animation studio and production company which was active from 1957 to 2001. It was founded on July 7, 1957, by William Hanna and Joseph Barbera following the decision of Metro-Goldwyn-Mayer to c ...
character Yogi Bear has appeared in numerous comic books, animated television shows and films. The Care Bears began as greeting cards in 1982, and were featured as toys, on clothing and in film. Around the world, many children—and some adults—have teddy bears, stuffed toys in the form of bears, named after the American statesman Theodore Roosevelt when in 1902 he had refused to shoot an American black bear tied to a tree. Bears, like other animals, may symbolize nations. The Russian Bear has been a common
national personification A national personification is an anthropomorphic personification of a state or the people(s) it inhabits. It may appear in political cartoons and propaganda. Some early personifications in the Western world tended to be national manifestations ...
for Russia from the 16th century onward. Smokey Bear has become a part of American culture since his introduction in 1944, with his message "Only you can prevent forest fires". File:The Three Bears - Project Gutenberg eText 17034.jpg, "The Three Bears", Arthur Rackham's illustration to ''English Fairy Tales'', by Flora Annie Steel, 1918 File:Sidney Hall - Urania's Mirror - Ursa Major.jpg, The
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...
of Ursa Major as depicted in
Urania's Mirror ''Urania's Mirror; or, a view of the Heavens'' is a set of 32 astronomical star chart cards, first published in November 1824. They are illustrations based on Alexander Jamieson's ''A Celestial Atlas'', but the addition of holes punched in them ...
, c. 1825


Organizations

The International Association for Bear Research & Management, also known as the International Bear Association, and the Bear Specialist Group of the Species Survival Commission, a part of the International Union for Conservation of Nature focus on the natural history, management, and conservation of bears. Bear Trust International works for wild bears and other wildlife through four core program initiatives, namely Conservation Education, Wild Bear Research, Wild Bear Management, and Habitat Conservation. Specialty organizations for each of the eight species of bears worldwide include: * Vital Ground, for the brown bear * Moon Bears, for the Asiatic black bear * Black Bear Conservation Coalition, for the North American black bear * Polar Bears International, for the polar bear * Bornean Sun Bear Conservation Centre, for the sun bear * Wildlife SOS, for the sloth bear * Andean Bear Conservation Project, for the Andean bear * Chengdu Research Base of Giant Panda Breeding, for the giant panda


See also

*
List of fictional bears This is a list of fictional bears that appear in video games, film, television, animation, comics and literature. This also includes pandas, but not the unrelated red panda species. The list is limited to notable, named characters. This list is a ...
* List of individual bears


Notes


References


Citations


General and cited references

*


Further reading

* * *


External links


The Bears Project – Information, reports and images of European brown bears and other living species

The Bear Book and Curriculum Guide – a compilation of stories about all eight species of bears worldwide, including STEM lessons rooted in bear research, ecology, and conservation
{{Authority control Articles containing video clips * Extant Eocene first appearances Predators Taxa named by Gotthelf Fischer von Waldheim