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Bears are carnivoran
mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
s of the family Ursidae (). They are classified as caniforms, or doglike carnivorans. Although only eight
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of bears are extant, they are widespread, appearing in a wide variety of
habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
s throughout most of the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...
and partially in the Southern Hemisphere. Bears are found on the continents of
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
,
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, and
Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...
. 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 polar bear is mostly carnivorous, and the giant panda is mostly herbivorous, the remaining six species are omnivorous with varying 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 a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...
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 prehistoric times for their meat and fur; they have also 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 The arts or creative arts are a vast range of human practices involving creative expression, storytelling, and cultural participation. The arts encompass diverse and plural modes of thought, deeds, and existence in an extensive range of m ...
, 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 market. The
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
lists six bear species as vulnerable or
endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
, and even
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
species, such as the brown bear, are at risk of extirpation in certain countries. The
poaching Poaching is the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the huntin ...
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 , or ), 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 developed from the languages brought to Great Britain by Anglo-S ...
' and belongs to a family of names for the bear in
Germanic languages The Germanic languages are a branch of the Indo-European languages, Indo-European language family spoken natively by a population of about 515 million people mainly in Europe, North America, Oceania, and Southern Africa. The most widely spoke ...
, such as Swedish ', also used as a first name. This form is conventionally said to be related to a
Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. No direct record of Proto-Indo-European exists; its proposed features have been derived by linguistic reconstruction from documented Indo-Euro ...
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. Bear taxon names such as
Arctoidea Arctoidea is an Order (biology), infraorder of mostly Carnivore, carnivorous mammals which include the extinct Hemicyoninae, Hemicyonidae (dog-bears), and the extant Musteloidea (weasels, raccoons, skunks, red pandas), Pinniped, Pinnipedia (seals ...
and '' Helarctos'' come from the ancient Greek ἄρκτος (''arktos''), meaning bear, as do the names "
arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...
" and "
antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...
", 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 first constellati ...
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 Christianity, Christian belief, a saint is a person who is recognized as having an exceptional degree of sanctification in Christianity, holiness, imitation of God, likeness, or closeness to God in Christianity, God. However, the use of the ...
'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 Bern (), or Berne (), ; ; ; . is the ''de facto'' Capital city, capital of Switzerland, referred to as the "federal city".; ; ; . According to the Swiss constitution, the Swiss Confederation intentionally has no "capital", but Bern has gov ...
is by legend 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 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, or "doglike" carnivorans, within the order Carnivora. Bears' closest living relatives are the
pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose onl ...
s, canids, and musteloids. (Some scholars formerly argued that bears are directly derived from canids and should not be classified as a separate family.) 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.


Evolution

The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including '' Parictis'' (late
Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...
to early middle
Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
, 38–18  Mya) and the slightly younger ''Allocyon'' (early
Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
, 34–30 Mya), both from North America. These animals looked very different from today's bears, being small and
raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...
-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
pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose onl ...
s, 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'' (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, 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. 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'' 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 sun bear (''Helarctos malayanus'') is a bear species in the Family (biology), family Ursidae found in the tropical forests of Southeast Asia. It is the only species in the genus ''Helarctos'' and the smallest bear species, standing nearly ...
, 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 The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
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, which is based on the molecular phylogenetic analysis of six genes in Flynn (2005) with the musteloids updated following the multigene analysis of Law et al. (2018). 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, 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. 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. Below is the cladogram based on McKenna and Bell (1997) classification:


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 North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...
and South American short-faced bears 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 Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
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 and the
pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...
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. 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 Bamboos are a diverse group of mostly evergreen perennial plant, perennial flowering plants making up the subfamily (biology), subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in th ...
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, 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 (anatomy), 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 ...
of bears appears to be the most basal of the caniforms. They possess air pouches connected to the
pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...
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 The cecum ( caecum, ; plural ceca or caeca, ) is a pouch within the peritoneum that is considered to be the beginning of the large intestine. It is typically located on the right side of the body (the same side of the body as the appendix (a ...
. Even the herbivorous giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes. Its ability to digest
cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...
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 The sun bear (''Helarctos malayanus'') is a bear species in the Family (biology), family Ursidae found in the tropical forests of Southeast Asia. It is the only species in the genus ''Helarctos'' and the smallest bear species, standing nearly ...
'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 is restricted to North America, and the polar bear is restricted to the Arctic Ocean. 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 a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...
, 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
scar A scar (or scar tissue) is an area of fibrosis, fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other Organ (anatomy), organs, and biological tissue, t ...
ring, 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 to locate other foods, encounter mates, avoid rivals and recognize their cubs.


Feeding

Most bears are opportunistic omnivores and consume more plant than animal matter, and appear to have evolved from an ancestor which was a low-protein macronutrient omnivore. They eat anything from leaves, roots, and berries to
insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...
s, carrion, 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 Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...
consume large numbers of
acorn The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), en ...
s when these are most common, and switch to
ungulate Ungulates ( ) are members of the diverse clade Euungulata ("true ungulates"), which primarily consists of large mammals with Hoof, hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined ...
s 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
grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...
es, 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 (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 (biology), family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the Tropics, tropical Americas, with several species found in the American subtropics and on ...
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
ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...
s,
termite Termites are a group of detritivore, detritophagous Eusociality, eusocial cockroaches which consume a variety of Detritus, decaying plant material, generally in the form of wood, Plant litter, leaf litter, and Humus, soil humus. They are dist ...
s, 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 bees for the
honey Honey is a sweet and viscous substance made by several species of 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 pl ...
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
rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...
s 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 sniffed 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 with raw strength, including bites and paw swipes, and bears do not display the specialized killing methods of felids and canids. Predatory behavior in bears is typically taught to the young by the mother. Bears are prolific scavengers and
kleptoparasite Kleptoparasitism (originally spelt clepto-parasitism, meaning "parasitism by theft") is a form of feeding in which one animal deliberately takes food from another. The strategy is Evolutionarily stable strategy, evolutionarily stable when stealin ...
s, 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 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 also communicate with their scent by urinating on or rubbing against trees and other objects. This is usually accompanied by clawing and biting the object. Bark may be spread around to draw attention to the marking post. Pandas establish territories by marking 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 and
serial monogamy Monogamy ( ) is a social relation, relationship of Dyad (sociology), two individuals in which they form a mutual and exclusive intimate Significant other, partnership. Having only one partner at any one time, whether for life or #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 pregn ...
typically lasts six to nine months, including delayed implantation, 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 two to three 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, 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 three to six 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 and the grizzly bear, 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. In order for their heart rate to slow down to this level during hibernation, a protein found in striated muscle, like the heart, called myosin must enter a super-relaxed state. In the super-relaxed state, the consumption of ATP is kept very low, allowing the bear to make it through the winter without losing all of its energy due to the basic functions such as pumping blood through the body. 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. While larger bears have a larger supply of body fat to keep them alive through hibernation, researchers found that smaller bears were able to hibernate longer than their larger counterparts due to them being able to sustain a lower body temperature, which translates to less energy being spent on keeping their bodies warm. 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.
Felid Felidae ( ) is the Family (biology), family of mammals in the Order (biology), order Carnivora colloquially referred to as cats. A member of this family is also called a felid ( ). The 41 extant taxon, extant Felidae species exhibit the gre ...
s like the
tiger The tiger (''Panthera tigris'') is a large Felidae, cat and a member of the genus ''Panthera'' native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur with black, mostly vertical stripes. It is ...
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'' sp., '' Strongyloides'' 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 market, though hunting is now banned, largely replaced by farming. The
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
lists six bear species as vulnerable; even the two
least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
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, 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 an The arts, art form, consisting of sequences of body movements with aesthetic and often Symbol, symbolic value, either improvised or purposefully selected. Dance can be categorized and described by its choreography, by its repertoir ...
, and were kept for baiting in Europe from at least the 16th century. There were five bear-baiting gardens in Southwark, London, at that time; archaeological remains of three of these have survived. Across Europe, nomadic Romani bear handlers called
Ursari The Ursari (generally read as "Bear-leader, bear leaders" or "bear handlers"; from the , meaning "bear"; singular: ''ursar''; Bulgarian language, Bulgarian: урсари, ''ursari'') or Richinara are the traditionally nomadic occupational group ...
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, 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, 1822 File:Theodor Aman - Ursarul.jpg, A nomadic '' ursar'', a Romani 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, though this is disputed by archaeologists. It is possible that bear worship existed in early Chinese and Ainu cultures. The prehistoric
Finns Finns or Finnish people (, ) are a Baltic Finns, Baltic Finnic ethnic group native to Finland. Finns are traditionally divided into smaller regional groups that span several countries adjacent to Finland, both those who are native to these cou ...
, Siberian peoples and more recently
Koreans Koreans are an East Asian ethnic group native to the Korean Peninsula. The majority of Koreans live in the two Korean sovereign states of North and South Korea, which are collectively referred to as Korea. As of 2021, an estimated 7.3 m ...
considered the bear as the spirit of their forefathers. Artio (''Dea Artio'' in the Gallo-Roman religion) was a Celtic bear goddess. Evidence of her worship has notably been found at
Bern Bern (), or Berne (), ; ; ; . is the ''de facto'' Capital city, capital of Switzerland, referred to as the "federal city".; ; ; . According to the Swiss constitution, the Swiss Confederation intentionally has no "capital", but Bern has gov ...
, itself named for the bear. Her name is derived from the Celtic word for "bear", ''artos''. In
ancient Greece Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...
, the archaic cult of
Artemis In ancient Greek religion and Greek mythology, mythology, Artemis (; ) is the goddess of the hunting, hunt, the wilderness, wild animals, transitions, nature, vegetation, childbirth, Kourotrophos, care of children, and chastity. In later tim ...
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 Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
. 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 ( years ago) ( ), also called the Old Stone Age (), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost the entire period of human prehist ...
times, in the widespread Cosmic Hunt 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". 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 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 Theodore Roosevelt Jr. (October 27, 1858 – January 6, 1919), also known as Teddy or T.R., was the 26th president of the United States, serving from 1901 to 1909. Roosevelt previously was involved in New York (state), New York politics, incl ...
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 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 first constellati ...
of Ursa Major as depicted in Urania's Mirror, 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 The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
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 * 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 Predatory animals Taxa named by Gotthelf Fischer von Waldheim Ursoidea