Physical Description of Brown Bear

Brown bears have very large and curved claws, those present on the forelimbs being longer than those on the hind limbs. They may reach 5 to 6 centimetres (2.0 to 2.4 in) and sometimes 7 to 10 centimetres (2.8 to 3.9 in) along the curve. They are generally dark with a light tip, with some forms having completely light claws. Brown bear claws are longer and straighter than those of American black bears. The claws are blunt, while those of a black bear are sharp.

Adults have massive, heavily built concave skulls, which are large in proportion to the body. The forehead is high and rises steeply. The projections of the skull are well developed when compared to those of Asian black bears: the latter have sagittal crests not exceeding more than 19–20% of the total length of the skull, while the former have sagittal crests comprising up to 40–41% of the skull's length.

Skull projections are more weakly developed in females than in males. The braincase is relatively small and elongated. There is a great deal of geographical variation in the skull, and presents itself chiefly in dimensions. Grizzlies, for example, tend to have flatter profiles than European and coastal American brown bears. Skull lengths of Russian bears tend to be 31.5 to 45.5 centimetres (12.4 to 17.9 in) for males, and 27.5 to 39.7 centimetres (10.8 to 15.6 in) for females. The width of the zygomatic arches in males is 17.5 to 27.7 centimetres (6.9 to 11 in), and 14.7 to 24.7 centimetres (5.8 to 9.7 in) in females.

Brown bears have very strong teeth: the incisors are relatively big and the canine teeth are large, the lower ones being strongly curved. The first three molars of the upper jaw are underdeveloped and single crowned with one root. The second upper molar is smaller than the others, and is usually absent in adults. It is usually lost at an early age, leaving no trace of the alveolus in the jaw. The first three molars of the lower jaw are very weak, and are often lost at an early age. Although they have powerful jaws, brown bear jaws are incapable of breaking large bones with the ease of spotted hyenas.

The dimensions of brown bears fluctuate very greatly according to sex, age, individual, geographic location, and season. The normal range of physical dimensions for a brown bear is a head-and-body length of 1.7 to 2.8 meters (5.6 to 9.2 ft) and a shoulder height of 90 to 150 centimeters (35–60 in). The smallest subspecies is the Eurasian brown bear, whose mature females weigh as little as 90 kg (200 lb). Barely larger, grizzly bears from the Yukon region (which are a third smaller than most grizzlies) can weigh as little as 100 kg (220 lb) in the spring and the Syrian brown bear, with mature females weighing as little as 150 kg (330 lb).

The largest subspecies are the Kodiak bear, Siberian brown bear, and the bears from coastal Russia, Alaska, and British Columbia. It is not unusual for large males in coastal regions to stand over 3 m (9.8 ft) while on their hind legs, and to weigh up to 680 kg (1,500 lb). The heaviest recorded brown bear weighed over 1,150 kilograms (2,500 lb). Brown bears have long, thick fur, with a moderately long mane at the back of the neck. In India, brown bears can be reddish with silver tips, while in China, brown bears are bicolored with a yellow-brown or whitish cape across the shoulders.

North American grizzlies can be dark brown (almost black) to cream (almost white) or yellowish brown. Black hairs usually have white tips. The winter fur is very thick and long, especially in northern subspecies, and can reach 11 to 12 centimetres (4 to 5 in) at the withers. The winter hairs are thin, yet rough to the touch. The summer fur is much shorter and sparser, and its length and density varies geographically.

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Grizzly – The Polar Bear Hybrid

A grizzly–polar bear hybrid (also pizzly bear, prizzly bear or grolar bear) is a rare ursid hybrid that has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA for a strange-looking bear that had been shot near Sachs Harbour, Northwest Territories on Banks Island in the Canadian Arctic. Ursid hybrids, a term that designates any hybrid of two species within the family Ursidae, include several other types of polar bear hybrids. Polar bear hybrids with grizzly bears in the wild have been reported and shot in the past as well, but DNA techniques were not available to verify the bears' ancestry.

With three confirmed cases and other suspected sightings, zoologists are hypothesizing how wild hybrids might come into being. Although the two species are genetically similar and often found in the same territories, they tend to avoid each other in the wild. They also fill different ecological niches. Grizzlies (and also Kodiak bears and "Alaskan brown bears", which are all subspecies of the brown bear, Ursus arctos), tend to live and breed on land. Polar bears prefer the water and ice, usually breeding on the ice. The yellowish-white MacFarlane's bear, a mysterious animal known only from one specimen acquired in 1864, seems to attest that grizzly-polar bear hybrids may have always occurred from time to time. Another theory suggests that the polar bears have been driven southward by the melting of the ice cap, bringing them into closer contact with grizzly bears.

On 8 April 2010, David Kuptana, an Inuvialuit hunter from the nearby community of Ulukhaktok on Victoria Island shot what he thought was a polar bear. After inspecting the bear and having DNA testing done, it was found that the bear's mother was a grizzly-polar hybrid and the father was a grizzly bear. The Department of Environment and Natural Resources for the NWT said that it "...may be the first recorded second-generation polar-grizzly bear hybrid found in the wild." The bear possesses physical characteristics intermediate between grizzlies and polar bears, such as brown fur on its paws, long claws and a grizzly-like head.

Biologists affiliated with the American Museum of Natural History and City College of the City University of New York have prepared a new report published in Canadian Field Naturalist that offers the first documented evidence that grizzlies are migrating into polar bear territory. Researchers found that seven grizzlies had been spotted in Wapusk National Park south of Churchill, Manitoba, between 2003 and 2008.

Since the 2006 discovery placed the hybrid into the spotlight, the media have referred to this animal with several portmanteau names, such as pizzly, grolar bear, and polizzly, but there is no consensus on the use of any one of these terms. Canadian wildlife officials have suggested calling the hybrid "nanulak", taken from the Inuit names for polar bear (nanuk) and grizzly bear (aklak). By one convention the name of the sire comes first in such combinations: the offspring of a male polar bear and a female grizzly would be the suggested nanulak or a "pizzly bear", while the offspring of a male grizzly and a female polar bear would be a "grolar bear" or possibly an aknuk. If the remains of MacFarlane's 1864 specimen - which was validly described according to ICZN rules - would be traced and confirmed to be such a hybrid by ancient DNA techniques, the scientific name Ursus × inopinatus would be available for these animals.

Two grizzly–polar bear hybrids were born at Osnabrück Zoo in 2004 (one female and one male), and their physical traits are generally an intermediate between the polar bear and the grizzly bear. For example, their bodies are smaller than polar bears, but larger than grizzlies, while their heads fall between the broader grizzly head and the leaner polar bear head. They have long necks like polar bears, but small shoulder humps like grizzlies. The soles of the hybrids' feet are partially covered in hair; polar bears have hair-covered soles, which act as insulation, and grizzlies have hairless soles. Similarly, the hair of the hybrids exhibits a pattern of hollowness, which blends the traits of both polar bears and grizzlies. In cross section, the hair of polar bears is hollow, while the hair of grizzlies is either solid or has small hollow regions.

This varies according to which part of the grizzly the hair is located. In the hybrid male, the paw hair was solid, but the dark back hair was somewhat hollow, albeit with "smaller empty regions than found in polar bear hair". The hair of the female hybrid, "contains a range of hollow regions". The hybrids demonstrated behavior more similar to polar bears than grizzlies. They stamped toys similar to how polar bears break ice, and hurled bags to the side "as polar bears may hurl prey". Grizzlies given the same bags do not demonstrate this hurling behavior. The hybrids were also observed lying down similar to polar bears: on their stomachs with rear legs splayed.

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Subspecies of Brown Bear

There is little agreement on classification of brown bears. Some systems have proposed as many as 90 subspecies, while recent DNA analysis has identified as few as five clades. DNA analysis recently revealed that the identified subspecies of brown bears, both Eurasian and North American, are genetically quite homogeneous, and that their genetic phylogeography does not correspond to their traditional taxonomy. As of 2005, 16 subspecies have been recognized. The subspecies have been listed as follows: 

East Siberian brown bear	Eurasian Brown Bear	Grizzly Bear
Himalayan Brown Bear	Kamchatka Brown Bear	Kodiak Bear
Syrian Brown Bear	Tibetan Blue Bear	Ussuri Brown Bear

Other subspecies of Brown Bear

Subspecies Name	Distribution	Description
Ursus Arctos Nelsoni – Mexican Grizzly Bear (Extinct)	Northern Mexico, including Chihuahua, Coahuila, and Sonora, southwestern United States including southern ranges of Texas, Arizona, and New Mexico	This bear is believed extinct due to cattle ranching in both the United States and Mexico. Distinct in its ability to survive arid conditions, it could live in both montane pine forests of Mexico and canyonlands of Sonoran Desert.
Ursus arctos sitkensis	Baranof Island	Appearing to be more closely related to the polar bear than to other brown bears, this species is called "clade I" by Waits, and others., and is part of the subspecies identified as U. a. sitkensis, by Hall and as U. a. dalli by Kurtén.
Ursus arctos marsicanus Marsican brown bear	Marsica (a small zone in Central Italy)	No Description
Ursus arctos stikeenensis	No information	No Description
Ursus arctos alascensis	Alaska	No Description
Ursus arctos californicus – California golden bear	California	No Description
Ursus arctos crowtheri – Atlas bear	California	No Description
Ursus arctos dalli	No information	No Description

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Ursus Arctos, The Brown Bear

The brown bear (Ursus arctos) is a large bear distributed across much of northern Eurasia and North America. It can weigh from 300 to 780 kilograms (660 to 1,700 lb) and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land-based predator.

There are several recognized subspecies within the brown bear species. In North America, two types are generally recognized, the coastal brown bear and the inland grizzly, and the two types could broadly define all brown bear subspecies. Grizzlies weigh as little as 350 lb (159 kg) in Yukon, while a brown bear, living on a steady, nutritious diet of spawning salmon, from coastal Alaska and Russia can weigh 1,500 lb (682 kg). The exact number of overall brown subspecies remains in debate. 

While the brown bear's range has shrunk, and it has faced local extinctions, it remains listed as a least concern species by the IUCN, with a total population of approximately 200,000. Its principal range countries are Russia, the United States (mostly in Alaska), Canada, the Carpathian region (especially Romania, but also Ukraine, Slovakia, and so on), the Balkans, Sweden and Finland, where it is the national animal. The brown bear is the most widely distributed of all bears. 

The brown bear is sometimes referred to as the bruin, from Middle English, based on the name of the bear in History of Reynard the Fox, translated by William Caxton, from Middle Dutch bruun or bruyn, meaning brown (the color). During the Old West, the grizzly was termed "Old Ephraim" and sometimes as "Moccasin Joe". Brown bears are thought to have evolved from Ursus etruscus. The oldest fossils occur in China from about 0.5 million years ago. They entered Europe about 250,000 years ago, and North Africa shortly after. 

Brown bear remains from the Pleistocene period are common in the British Isles, where it is thought they outcompeted cave bears. The species entered Alaska 100,000 years ago, though they did not move south until 13,000 years ago. It is thought brown bears were unable to migrate south until the extinction of the much larger Arctodus simus. Several paleontologists suggest the possibility of two separate brown bear migrations: grizzlies are thought to stem from narrow-skulled bears which migrated from northern Siberia to central Alaska and the rest of the continent, while Kodiak bears descend from broad-skulled bears from Kamchatka, which colonized the Alaskan peninsula. Brown bear fossils discovered in Ontario, Ohio, Kentucky and Labrador show the species occurred farther east than indicated in historic records.

See Also : 

• Subspecies of Brown Bear
• Grizzly - Polar Bear Hybrid
• Physical Description of Brown Bear
• Distribution and Habitat of Brown Bear
• Behavior Brown Bear

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Bear - The Monster of Carnivora

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 is 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". 

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: Upper: 3.1.2-4.2, lower: 3.1.2-4.3 

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)

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