Bear, Bear

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. That which pertains to bears is called ursine . Bears are found in the continents of North America, South America, Europe, and Asia.

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' closest living relatives are the pinnipeds, a clade of three families: Odobenidae (the walrus), Otariidae (fur seals and sea lions), and Phocidae (true or earless seals). 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).thumb|left|Unlike other carnivora, bears have hind feet ]The origins of Ursidae can be traced back to the very small and graceful Parictis that had a skull only 7 cm (3 in) long. Parictis first occur in North America in the Late Eocene (ca. 38 million years ago), but this genus did not appear in Eurasia and Africa until the Miocene.

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.

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.

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 kg. There is some difficulty in assigning which species is the largest; it depends on whether you use which species has the largest individuals (brown bears) or the largest average size (polar bears). The smallest bears are the Sun Bears of Asia, which weigh an average of 65 kg for the males and 45 kg for the females.

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.

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 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.

Some species, particularly the Brown Bear, may inhabit or seasonally use other areas such as alpine scrub or tundra.

The belief that they are nocturnal apparently comes from the habits of bears that live near humans which engage in some activities, such as raiding trash cans or crops, are nocturnal in order to avoid 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.

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.

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 ) shos that it was also an exclusive meat eater, probably a scavenger.

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.

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 13, 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 learn to begin hunting with the mother.

While many bear species do go into a physiological state 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.

On the west coast of Canada, the American black bear has become an integral part of the silviculture industries, specifically treeplanting. The bears are coaxed into areas of harvested forest to "flush out" the other wildlife, i.e. moose, which are a far greater threat to planters. All bears are physically powerful and are likely capable of fatally attacking a person, but they, for the most part, are shy, easily frightened and will avoid humans. Injuries caused by bears are rare, but are often widely reported.

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.

In the arms of the bishopric of Freising ( see illustration ) the bear is the dangerous totem animal tamed by St. Corbinian and made to carry his civilised baggage over the mountains.A bear also features prominently in the legend of St. Romedius, who is also said to have tamed one of these animals and had the same bear carry him from his hermitage in the mountains to the city of Trento.

Michel Pastoreau (2007) L'ours. Historie d'un roi dchu 's illustration to English Fairy Tales , byFlora Annie Steel Imaginary bears are a popular feature of many children's stories including Goldilocks and the Three Bears, the Berenstein Bears, and Winnie the Pooh.

The use of this name is ancient and has been found mentioned in several runestone inscriptions. http://hildebrand.raa.se/arkeologi/uppland.asp The name was also used by J.R.R. Tolkien in his book "The Hobbit", where a bear-like character is named Beorn.

Also among other Native American tribes, bear-related names are attested.

Source: Wikipedia > Bear