Temporal range: 38–0 Ma Late Eocene – Recent
|Brown bear, Ursus arctos in Norway|
G. Fischer de Waldheim, 1817
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found in the continents of North America, South America, Europe, and Asia.
Common characteristics of modern bears include a large body with stocky legs, a long snout, shaggy hair, plantigrade paws with five nonretractile claws, and a short tail. While the polar bear is mostly carnivorous and the giant panda feeds almost entirely on bamboo, the remaining six species are omnivorous, with largely varied diets including both plants and animals.
With the exceptions of courting individuals and mothers with their young, bears are typically solitary animals. They are generally diurnal, but may be active during the night (nocturnal) or twilight (crepuscular), particularly around humans. Bears are aided by an excellent sense of smell, and despite their heavy build and awkward gait, they can run quickly and are adept climbers and swimmers. In autumn some bear species forage large amounts of fermented fruits which affects their behaviour. Bears use shelters such as caves and burrows as their dens, which are occupied by most species during the winter for a long period of sleep similar to hibernation.
Bears have been hunted since prehistoric times for their meat and fur. To this day, they play a prominent role in the arts, mythology, and other cultural aspects of various human societies. In modern times, the bear's existence has been pressured through the encroachment on its habitats and the illegal trade of bears and bear parts, including the Asian bile bear market. The IUCN lists six bear species as vulnerable 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.
The English word "bear" comes from Old English bera and belongs to a family of names for the bear in Germanic languages, in origin from an adjective meaning "brown". In Scandinavia the word for bear is björn (or bjørn), and is a relatively common given name for males. The use of this name is ancient and has been found mentioned in several runestone inscriptions. In Germanic culture, the bear was a symbol of the warrior, as evident from the Old English term beorn which can take the meaning of both "bear" and "warrior".
The reconstructed Proto-Indo-European name of the bear is *h₂ŕ̥tḱos, whence Sanskrit r̥kṣa, Avestan arša, Greek ἄρκτος (arktos), Latin ursus, Welsh arth (whence perhaps "Arthur"), Albanian ari, Armenian arj. Also compared is Hittite ḫartagga-, the name of a monster or predator. In the binomial name of the brown bear, Ursus arctos, Linné simply combined the Latin and Greek names.
The Proto-Indo-European word for bear, *h₂ŕ̥tḱos seems to have been subject to taboo deformation or replacement in some languages (as was the word for wolf, wlkwos), resulting in the use of numerous unrelated words with meanings like "brown one" (English bruin) and "honey-eater" (Slavic medved). Thus some Indo-European language groups do not share the same PIE root. The theory of the bear taboo is taught to almost all beginning students of Indo-European and historical linguistics; the putative original PIE word for bear is itself descriptive, because a cognate word in Sanskrit is rakṣas, meaning "harm, injury".
The following synapomorphic (derived) traits set bears apart from related families:
- presence of an alisphenoid canal
- paroccipital processes that are large and not fused to the auditory bullae
- auditory bullae are not enlarged
- lacrimal bone is vestigial
- cheek teeth are bunodont and hence indicative of a broad, hypocarnivorous (non-strictly meat-eating) diet (although hypercarnivorous (strictly meat-eating) taxa are known from the fossil record)
- carnassials are flattened
Additionally, members of this family possess posteriorly oriented M2 postprotocrista molars, elongated m2 molars, and a reduction of the premolars.
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 upon authority).
The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including Parictis (late Eocene to early middle Miocene, 38–18 million years (Ma) ago) and the slightly younger Allocyon (early Oligocene, 34–30 Ma), both from North America. These animals looked very different from today's bears, being small and raccoon-like in overall appearance, and a diet 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 (~37 Ma) and continuing into the early Oligocene. European genera morphologically very similar to Allocyon, and also the much younger American Kolponomos (~18 Ma), are known from the Oligocene, including Amphicticeps and Amphicynodon.Cephalogale is the oldest-known member of the subfamily Hemicyoninae which first appeared during the middle Oligocene in Eurasia ~30 Ma ago. The subfamily also includes the younger genera Phoberocyon (~ 20–15 Ma), and Plithocyon (~ 15–7 Ma).
A Cephalogale-like species gave rise to the genus Ursavus during the early Oligocene (30–28 Ma); 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 Ma).
Members of living lineages of bears diverged from Ursavus ~20 Ma ago, likely via the species Ursavus elmensis. Based on genetic and morphological data, the subfamily Ailuropodinae (pandas) was the first to diverge from other living bears ~19 Ma ago, although no fossils of this group have been found pre-dating about 5 Ma.
The New World short-faced bears (Tremarctinae) differentiated from Ursinae following a dispersal event into North America during the mid Miocene (~13 Ma). They invaded South America (~1 Ma) following formation of the Isthmus of Panama. Their earliest fossil representative is Plionarctos in North America (~ 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).Ursinae experienced a dramatic proliferation of taxa ~5.3-4.5 Ma ago coincident with major environmental changes, with the first members of the genus Ursus also appearing around this time. The sloth bear is a modern survivor of one of the earliest lineages to diverge during this radiation event (~5.3 Ma); it took on its peculiar morphology related to its diet on termites and ants no later than by the early Pleistocene. By 3–4 Ma ago, the species Ursus minimus appears in the fossil record of Europe, which apart from size is nearly identical to today's Asiatic 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 Asiatic black bear, and the American black bear), and the brown bears. Modern brown bears evolved from U. minimus via Ursus etruscus, which itself is ancestral to both the extinct Pleistocene cave bear and today's brown and polar bears. Species of Ursinae have migrated repeatedly into N. America from Eurasia as early as 4 Ma ago during the early Pliocene.
The fossil record of bears is exceptionally good. Direct ancestor-descendent relationships between individual species are often fairly well established, with sufficient intermediate forms known to make the precise cut-off between an ancestral and its daughter species subjective.
Taxonomic revisions of living bear species
The giant panda's taxonomy (subfamily Ailuropodinae) has long been debated. Its original classification by Armand David in 1869 was within the bear genus Ursus, but in 1870 it was reclassified by Alphonse Milne-Edwards to the raccoon family. In recent studies, the majority of DNA analyses suggest that the giant panda has a much closer relationship to other bears and should be considered a member of the family Ursidae. Estimates of divergence dates place the giant panda as the most ancient offshoot among living taxa within Ursidae, having split from other bears 17.9 to 22.1 Ma ago. The red panda was included within Ursidae in the past. However, more recent research does not support such a conclusion and instead places it in its own family Ailuridae, in superfamily Musteloidea along with Mustelidae, Procyonidae, and Mephitidae. Multiple similarities between the two pandas, including the presence of false thumbs, are thus thought to represent an example of convergent evolution for feeding primarily on bamboo.
There is also evidence that, unlike their neighbors elsewhere, the brown bears of Alaska's ABC islands are more closely related to polar bears than they are to other brown bears in the world. Researchers Gerald Shields and Sandra Talbot of the University of Alaska Fairbanks Institute of Arctic Biology studied the DNA of several samples of the species and found that their DNA is different from that of other brown bears. The researchers discovered that their DNA was unique compared to brown bears anywhere else in the world. The discovery has shown that while all other brown bears share a brown bear as their closest relative, those of Alaska's ABC Islands differ and share their closest relation with the polar bear. There is also the very rare Tibetan blue bear, which is a type of brown bear. This animal has never been photographed.
- Family Ursidae
- Subfamily Ailuropodinae
- † Ailurarctos
- † Ailurarctos lufengensis
- † Ailurarctos yuanmouenensis
- Ailuropoda (pandas)
- † Ailurarctos
- Subfamily Tremarctinae
- Tremarctos (Spectacled bears)
- † Arctodus
- † Arctodus simus
- † Arctodus pristinus
- † Arctotherium
- † Arctotherium angustidens
- † Arctotherium bonariense
- † Arctotherium brasilense
- † Arctotherium latidens
- † Arctotherium tarijense
- † Arctotherium vetustum
- † Arctotherium wingei
- † Plionarctos
- † Plionarctos edensis
- † Plionarctos harroldorum
- Subfamily Ursinae
- † Agriotherium
- † Agriotherium inexpetans
- † Agriotherium schneideri
- † Agriotherium sivalensis
- † Indarctos
- † Indarctos anthraciti
- † Indarctos arctoides
- † Indarctos atticus
- † Indarctos nevadensis
- † Indarctos oregonensis
- † Indarctos salmontanus
- † Indarctos vireti
- † Indarctos zdanskyi
- † Ursavus
- † Ursavus brevirhinus
- † Ursavus depereti
- † Ursavus elmensis
- † Ursavus pawniensis
- † Ursavus primaevus
- † Ursus abstrusus
- Ursus americanus, American black bear
- Ursus americanus altifrontalis, Olympic black bear
- Ursus americanus amblyceps, New Mexico black bear
- Ursus americanus americanus, Eastern black bear
- Ursus americanus californiensis, California black bear
- Ursus americanus carlottae, Haida Gwaii black bear or Queen Charlotte black bear
- Ursus americanus cinnamomum, cinnamon bear
- Ursus americanus emmonsii, Glacier bear
- Ursus americanus eremicus, Mexican black bear
- Ursus americanus floridanus, Florida black bear
- Ursus americanus hamiltoni, Newfoundland black bear
- Ursus americanus kermodei, Kermode bear or spirit bear
- Ursus americanus luteolus, Louisiana black bear
- Ursus americanus machetes, West Mexico black bear
- Ursus americanus perniger, Kenai black bear
- Ursus americanus pugnax, Dall black bear
- Ursus americanus vancouveri, Vancouver Island black bear
- Ursus arctos, brown bear
- Ursus arctos arctos, Eurasian brown bear
- Ursus arctos alascensis
- Ursus arctos beringianus, Kamchatka brown bear or Far Eastern brown bear
- † Ursus arctos californicus, California golden bear
- † Ursus arctos crowtheri, Atlas bear
- † Ursus arctos dalli
- Ursus arctos gobiensis, Gobi bear (very rare)
- Ursus arctos horribilis, grizzly bear
- Ursus arctos isabellinus, Himalayan brown bear or Himalayan red bear
- Ursus arctos lasiotus, Ussuri brown bear or black grizzly
- Ursus arctos middendorffi, Kodiak bear
- † Ursus arctos nelsoni, Mexican grizzly bear
- Ursus arctos piscator, Bergman's bear (extinct?)
- Ursus arctos pruinosus, Tibetan blue bear or Tibetan bear or Himalayan blue bear
- Ursus arctos sitkensis
- Ursus arctos syriacus Syrian (brown) bear
- † Ursus deningeri
- † Ursus etruscus
- † Ursus inopinatus, MacFarlane's bear (cryptid; if an authentic species, extinct)
- † Ursus minimus
- Ursus maritimus, polar bear
- † Ursus rossicus
- † Ursus sackdillingensis
- † Ursus spelaeus, cave bear
- Ursus thibetanus, Asian black bear
- † Agriotherium
- † Kolponomos
- † Kolponomos clallamensis
- † Kolponomos newportensis
- Subfamily Ailuropodinae
The genera Melursus and Helarctos are sometimes also included in Ursus. The Asiatic black bear and the polar bear used to be placed in their own genera, Selenarctos and Thalarctos which are now placed at subgenus rank.
A number of hybrids have been bred between American black, brown, and polar bears (see Ursid hybrids).
Bears are generally bulky and robust animals with relatively short legs. Bears are sexually dimorphic with regard to size, with the males being larger. Larger species tend to show increased levels of sexual dimorphism in comparison to smaller species, and where a species varies in size across its distribution individuals from larger sized areas tend also to vary more. Bears are the most massive terrestrial members of the order Carnivora, with some Polar Bears and Brown Bears weighing over 750 kilograms (1,650 lb). As to which species is the largest may depend on whether the assessment is based on which species has the largest individuals (brown bears) or on the largest average size (polar bears). The smallest bears are the Sun Bears of Asia, which weigh an average of 65 kilograms (143 lb) for the males and 45 kilograms (99 lb) for the females.
Unlike other land carnivorans, bears are plantigrade. They distribute their weight toward the hind feet which makes them look lumbering when they walk. They are still quite fast with the brown bear reaching 30 miles per hour (48 km/h) although they are still slower than felines and canines. Bears can stand on their hind feet and sit up straight with remarkable balance. Bears have non-retractable claws which are used for digging, climbing, tearing and catching prey. Their ears are rounded.
Bears have an excellent sense of smell, a better sense of smell than the dogs (Canidae), or possibly any other mammal. This sense of smell is used for signalling between bears (either to warn off rivals or detect mates) and for finding food. Smell is the principal sense used by bears to find most of their diet.
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. The canine teeth are large, and the molar teeth flat and crushing. There is considerable variation in dental formula even within a given species. It has been suggested that this indicates bears are still in the process of evolving from a carnivorous to a predominantly herbivorous diet. Polar bears appear to have secondarily re-evolved fully functional carnassials, as their diet has switched back towards carnivory. The dental formula for living bears is: Unknown extension tag "math"
Distribution and habitat
The bears are mostly found in the northern hemisphere, with a single species, the spectacled bear, occurring in South America. The Atlas Bear, a subspecies of the Brown Bear, was the only bear native to Africa. It was distributed in North Africa from Morocco to Libya, but has been extinct since around the 1870s. All the other species are found in North America, Asia and Europe. The most widespread species is the Brown Bear, which occurs from Western Europe eastwards through Asia to the western areas of North America. The American Black Bear is restricted to North America, and the Polar bear is restricted to the Arctic Sea. All the remaining species are Asian.
With the exception of the Polar Bear the bears are mostly forest species. Some species, particularly the Brown Bear, may inhabit or seasonally use other areas such as alpine scrub or tundra.
While many people think that bears are nocturnal, they are in fact generally diurnal, active for the most part during the day. The belief that they are nocturnal apparently comes from the habits of bears that live near humans which engage in some nocturnal activities, such as raiding trash cans or crops while avoiding humans. The sloth bear of Asia is the most nocturnal of the bears, but this varies by individual and females with cubs are often diurnal in order to avoid competition with males and nocturnal predators. Bears are overwhelmingly solitary and are considered to be the most asocial of all the Carnivora. Liaisons between breeding bears are brief, and the only times bears are encountered in small groups are mothers with young or occasional seasonal bounties of rich food (such as salmon runs).
Bears produce a variety of vocalizations such as:
- Moaning: produced mostly as mild warnings to potential threats or in fear.
- Barking: produced during times of alarm, excitement or to give away the animal's position.
- Huffing: made during courtship or between mother and cubs to warn of danger.
- Growling: produced as strong warnings to potential threats or in anger.
- Roaring: used much for the same reasons as growls and also to proclaim territory and for intimidation.
Diet and interspecific interactions
Their carnivorous reputation non-withstanding, most bears have adopted a diet of more plant than animal matter and are completely opportunistic omnivores. Some bears will climb trees in order to obtain mast (edible vegatative or reproductive parts such as acorns); smaller species which are more able to climb include a greater amount of this in their diet. Such masts can be very important to the diet of these species, and mast failures may result in long range movements by bears looking for alternative sources of food. One exception is the polar bear, which has adopted a diet mainly of marine mammals to survive in the Arctic. The other exception is the giant panda which has adopted a diet mainly of bamboo. Stable isotope analysis of the extinct giant short-faced bear (Arctodus simus) shows that it was also an exclusive meat eater, probably a scavenger. The sloth bear, though not as specialized as the previous two species, has lost several front teeth usually seen in bears and developed a long, suctioning tongue in order to feed on the ants, termites and other burrowing insects that they favour. At certain times of the year these insects can make up 90% of their diet. All bears will feed on any food source that becomes available, and the nature of that varies seasonally. A study of Asiatic black bears in Taiwan found that they would consume large numbers of acorns when they were most common, and switch to ungulates in other times of the year.
When taking warm-blooded animals, bears will typically take small or young animals, as they are easier to catch. Although (besides polar bears) both species of black bear and the brown bear can sometimes take large prey, such as ungulates. Often, bears will feed on other large animals when they encounter a carcass, whether or not the carcass is claimed by or is the kill of another predator. This competition is the main source of interspecies conflict. Bears are typically the apex predators in their range due to their size and power, and can defend a carcass against nearly all comers. Mother bears also can usually defend their cubs against other predators. The tiger is the only known predator known to regularly prey on adult bears, including sloth bears, Asiatic black bears, giant pandas, sun bears and small brown bears.
The age at which bears reach sexual maturity is highly variable, both between and within species. Sexual maturity is dependent on body condition, which is in turn dependent upon the food supply available to the growing individual. In the females of smaller species may have young in as little as two years, whereas the larger species may not rear young until they are four or even nine years old. First breeding may be even later in males, where competition for mates may leave younger males without access to females.
The bear's courtship period is very brief. Bears in northern climates reproduce seasonally, usually after a period of inactivity similar to hibernation, although tropical species breed all year round. Cubs are born toothless, blind, and bald. The cubs of brown bears, usually born in litters of 1–3, will typically stay with the mother for two full seasons. They feed on their mother's milk through the duration of their relationship with their mother, although as the cubs continue to grow, nursing becomes less frequent and cubs learn to begin hunting with the mother. They will remain with the mother for approximately three years, until she enters the next cycle of estrus and drives the cubs off. Bears will reach sexual maturity in five to seven years. Male bears, especially Polar and Brown Bears, will kill and sometimes devour cubs born to another father in order to induce a female to breed again. Female bears are often successful in driving off males in protection of their cubs, despite being rather smaller.
Many bears of northern regions are assumed[by whom?] to hibernate in the winter. While many bear species[which?] do go into a physiological state often colloquially called "hibernation" or "winter sleep", it is not true hibernation. In true hibernators, body temperatures drop to near ambient and heart rate slows drastically, but the animals periodically rouse themselves to urinate or defecate and to eat from stored food. The body temperature of bears, on the other hand, drops only a few degrees from normal and heart rate slows only slightly. They normally do not wake during this "hibernation", and therefore do not eat, drink, urinate or defecate the entire period. Higher body heat and being easily roused may be adaptations, because females give birth to their cubs during this winter sleep.
Relationship with humans
Some species, such as the polar bear, American black bear, sloth bear and the brown bear, are dangerous to humans, especially in areas where they have become used to people. All bears are physically powerful and are likely capable of fatally attacking a person, but they, for the most part, are shy, are easily frightened and will avoid humans. Injuries caused by bears are rare, but are often widely reported. The danger that bears pose is often vastly exaggerated, in part by the human imagination. However, when a mother feels her cubs are threatened, she will behave ferociously. It is recommended to give all bears a wide berth because they are behaviorally unpredictable.
Bears may also come into conflict with humans where they raid crops or attack livestock. These problems may be the work of only a few bears but create a climate of conflict as farmers and ranchers may perceive all losses as due to bears and advocate the preventive removal of all bears. Mitigation methods may be used to reduce bear damage to crops, and reduce local antipathy towards bears.
Laws have been passed in many areas of the world to protect bears from hunters' habitat destruction. Public perception of bears is often very positive, as people identify with bears due to their omnivorous diet, ability to stand on two legs, and symbolic importance, and there is widespread support for bear protection, at least in more affluent societies. In more rural and poorer regions attitudes may be more shaped by the dangers posed by bears and the economic costs that they incur to farmers and ranchers. Some populated areas with bear populations have also outlawed the feeding of bears, including allowing them access to garbage or other food waste. Bears in captivity have been trained to dance, box, or ride bicycles; however, this use of the animals became controversial in the late 20th century. Bears were kept for baiting in Europe at least since the 16th century.
Some cultures use bears for 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. The peoples of China, Japan, and Korea use bears' body parts and secretions (notably their gallbladders and bile) as part of traditional Chinese medicine. It is believed more than 12,000 bile bears are kept on farms, farmed for their bile, in China, Vietnam and South Korea. Bear meat must be cooked thoroughly as it can often be infected with Trichinella spiralis, which can cause trichinosis.
The female first name "Ursula", originally derived from a Christian saint's name and common in English- and German-speaking countries, means "little she-bear" (diminutive of Latin ursa). In Switzerland the male first name "Urs" is especially popular, while the name of the canton and city of Bern is derived from Bär, German for bear.
In Scandinavia, the male personal names Björn (Sweden, Iceland) and Bjørn (Norway, Denmark) meaning "bear" are relatively common. In Finland, male personal name Otso is an old poetic name for bear, similar to Kontio.
In East European Jewish communities, the name "Ber" (בער) — Yiddish cognate of "Bear" — has been attested as a common male first name, at least since the 18th century, and was among others the name of several prominent Rabbis. The Yiddish "Ber" is still in use among Orthodox Jewish communities in Israel, the US and other countries. With the transition from Yiddish to Hebrew under the influence of zionism, the Hebrew word for "bear", "Dov" (דב), was taken up in contemporary Israel and is at present among the commonly used male first names in that country.
Organizations regarding bears
There are at least two authoritative organizations for seeking scientific information on bear species of the world. These focus on, for example, the species' natural history, management, and conservation. The International Association for Bear Research & Management is also known as the International Bear Association (IBA). The Bear Specialist Group of the Species Survival Commission is part of the International Union for the Conservation of Nature.
- Bear hunting
- List of fatal bear attacks in North America
- List of fictional bears
- List of non-fictional bears
- "Slovakia warns of tipsy bears". Archived from the original on 2010-11-18. Retrieved 2008-11-11.
- Pokorny (1959) indo-european.nl
- Votruba, Martin. "Bears". Slovak Studies Program. University of Pittsburgh. Archived from the original on 2010-11-18. Retrieved 2009-03-12.
- "The Brown One, The Honey Eater, The Shaggy Coat, The Destroyer". Cloudline.org. Archived from the original on 2010-11-18. Retrieved 2010-10-16.
- Welsey-Hunt, G.D. & Flynn, J.J. (2005). "Phylogeny of the Carnivora: basal relationships among the Carnivoramorphans, and assessment of the position of ‘Miacoidea’ relative to Carnivora". Journal of Systematic Palaeontology 3 (1): 1–28. doi:10.1017/S1477201904001518.
- Wang, Xiaoming, Malcolm C. McKenna, and Demberelyin Dashzeveg (2005). "Amphicticeps and Amphicynodon (Arctoidea, Carnivora) from Hsanda Gol Formation, Central Mongolia and Phylogeny of Basal Arctoids with Comments on Zoogeography". American Museum Novitates (3483): 57.[dead link]
- Kemp, T.S. (2005). The Origin and Evolution of Mammals. Oxford University Press. ISBN 978-0-19-850760-4.
- Wang Banyue and Qiu Zhanxiang (2005). "Notes on Early Oligocene Ursids (Carnivora, Mammalia) from Saint Jacques, Nei Mongol, China" (PDF). Bulletin of the American Museum of Natural History 279 (279): 116–124. doi:10.1206/0003-0090(2003)279<0116:C>2.0.CO;2. Archived from the original on 2009-11-20.
- Krause, J.; Unger, T.; Noçon, A.; Malaspinas, A.; Kolokotronis, S.; Stiller, M.; Soibelzon, L.; Spriggs, H.; Dear, P. H.; Briggs, A. W.; Bray, S. C. E.; O'Brien, S. J.; Rabeder, G.; Matheus, P.; Cooper, A.; Slatkin, M.; Pääbo, S.; Hofreiter, M. (2008-07-28). "Mitochondrial genomes reveal an explosive radiation of extinct and extant bears near the Miocene-Pliocene boundary". BMC Evolutionary Biology 8 (220): 220. PMC 2518930. PMID 18662376. doi:10.1186/1471-2148-8-220.
- Soibelzon, L. H.; Tonni, E. P.; Bond, M. (October 2005). "The fossil record of South American short-faced bears (Ursidae, Tremarctinae)". Journal of South American Earth Sciences 20 (1–2): 105–113. doi:10.1016/j.jsames.2005.07.005.
- Qiu Zhanxiang (2003). "Dispersals of Neogene Carnivorans between Asia and North America" (PDF). Bulletin American Museum of Natural History 279 (279): 18–31. doi:10.1206/0003-0090(2003)279<0018:C>2.0.CO;2. Archived from the original on 2009-11-20.
- Kurtén, B., 1995. The cave bear story: life and death of a vanished animal, Björn Kurtén, Columbia University Press
- Lindburg, Donald G. (2004). Giant Pandas: Biology and Conservation, pp. 7–9. University of California Press
- Olaf R. P. Bininda-Emonds. "Phylogenetic Position of the Giant Panda". In Lindburg, Donald G. (2004) Giant Pandas: Biology and Conservation, pp. 11–35. University of California Press
- Flynn, J. J.; Nedbal, M. A.; Dragoo, J. W.; Honeycutt, R. L. (2000). "Whence the Red Panda?". Molecular Phylogenetics and Evolution 17 (2): 190–199. PMID 11083933. doi:10.1006/mpev.2000.0819. Retrieved 2009-09-23.
- Flynn, J. J.; 2, J. A.; Zehr, S.; 3, J.; Nedbal, M. A. (2005). "Molecular phylogeny of the carnivora (mammalia): assessing the impact of increased sampling on resolving enigmatic relationships". Systematic Biology 54 (2): 317–337. PMID 16012099. doi:10.1080/10635150590923326. Archived from the original on 2010-11-18. Retrieved 2009-10-08.
- Flynn, J. J.; Nedbal, M. A. (1998). "Abstract". Molecular Phylogenetics and Evolution 9 (3): 414–426. PMID 9667990. doi:10.1006/mpev.1998.0504. Archived from the original on 2010-11-18.. Retrieved 2009-10-08.
- "The Brown Bear: Father of the Polar Bear?, Alaska Science Forum". Gi.alaska.edu. 1996-12-05. Archived from the original on 2010-01-17. Retrieved 2010-10-16.
- Garshelis, David L. (2009). "Family Ursidae (Bears)". In Wilson, Don; Mittermeier, Russell. Handbook of the Mammals of the World. Volume 1: Carnivores. Barcelona: Lynx Edicions. ISBN 978-84-96553-49-1.
- Bunnell, Fred (1984). Macdonald, D., ed. The Encyclopedia of Mammals. New York: Facts on File. p. 87. ISBN 978-0-87196-871-5.
- Mattson, David J. (1998). "Diet and Morphology of Extant and Recently Extinct Northern Bears". Ursus, A Selection of Papers from the Tenth International Conference on Bear Research and Management, Fairbanks, Alaska, July 1995, and Mora, Sweden, September 1995 10: 479–496. JSTOR 3873160.
- Ryan, Christopher; Pack, James C.; Igo, William K.; Billings, Anthony (2007). "Influence of mast production on black bear non-hunting mortalities in West Virginia". Ursus 18 (1): 46–53. doi:10.2192/1537-6176(2007)18[46:IOMPOB]2.0.CO;2.
- Matheus, Paul E. (1995). "Diet and Co-ecology of Pleistocene Short-Faced Bears and Brown Bears in Eastern Beringia". Quaternary Research 44 (3): 447–453. doi:10.1006/qres.1995.1090.
- Joshi, Anup (1997). "Seasonal and Habitat-Related Diets of Sloth Bears in Nepal". Journal of Mammalology 1978 (2): 584–597.
- Hwang, Mei-Hsiu (2002). "Diets of Asiatic black bears in Taiwan, with Methodological and Geographical Comparisons". Ursus 13: 111–125.
- Zager, Peter; Beecham, John (2006). "The role of American black bears and brown bears as predators on ungulates in North America". Ursus 17 (2): 95–108. doi:10.2192/1537-6176(2006)17[95:TROABB]2.0.CO;2.
- Clark, Douglas (2003). "Polar Bear–Human Interactions in Canadian National Parks, 1986–2000". Ursus 14 (1): 65–71.
- Fredriksson, Gabriella (2005). "Human–sun bear conflicts in East Kalimantan, Indonesian Borneo". Ursus 16 (1): 130–137. doi:10.2192/1537-6176(2005)016[0130:HBCIEK]2.0.CO;2.
- Goldstein, Isaac; Paisley, Susanna; Wallace, Robert; Jorgenson, Jeffrey P.; Cuesta, Francisco; Castellanos, Armando (2006). "Andean bear–livestock conflicts: a review". Ursus 17 (1): 8–15. doi:10.2192/1537-6176(2006)17[8:ABCAR]2.0.CO;2.
- Kellert, Stephen (1994). "Public Attitudes toward Bears and Their Conservation". Bears: Their Biology and Management 9 (1): 43–50. JSTOR 3872683. doi:10.2307/3872683.
- Andersone, Žanete; Ozolinš, Jānis (2004). "Public perception of large carnivores in Latvia". Ursus 15 (2): 181–187. doi:10.2192/1537-6176(2004)015<0181:PPOLCI>2.0.CO;2.
- Black, Richard (2007-06-11). "BBC Test kit targets cruel bear trade". BBC News. Archived from the original on 2010-11-18. Retrieved 2010-01-01.
- "Trichinellosis Associated with Bear Meat". Retrieved 2006-10-04.
- "BBC News - Bear meat poisoning in Siberia". 1997-12-21. Retrieved 2006-10-04.
- "Finnish Food Safety Authority: Bear meat must be inspected before serving in restaurants". Retrieved 2006-10-04.
- Bears of the World, Terry Domico, photographs by Terry Domico and Mark Newman, Facts on File, Inc, 1988, hardcover, ISBN 978-0-8160-1536-8.
- The Bear by William Faulkner.
- Brunner, Bernd: Bears — A Brief History. New Haven and London: Yale University Press, 2007.