Brown Bear
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Brown Bear
The Brown Bear (Ursus arctos) is an omnivorous mammal of the family Ursidae, distributed across much of northern Eurasia and North America. It weighs between 100?700 kg (220-1,500 pounds) and its larger populations such as the Kodiak bear match the Polar bear as the largest extant land carnivores. While the brown bear's range has shrunk, and it has faced local extinctions, it remains listed as a least concern species with a total population of approximately 200,000. Its principal range countries are Russia, the United States (especially Alaska), Canada, and Finland where it is the national animal. The species primarily feeds on vegetable matter, including roots and fungi. Fish are a primary source of meat, and it will also kill small mammals on land. Larger mammals, such as deer, are taken only occasionally. Adult brown bears face no serious competition from other predators and can match wolf packs and large felines, often driving them off their kills. It 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.
Description
A Eurasian Brown Bear running. Brown bears can be fast runners despite their size, capable of speeds of up to 56 km/h (35 mph) Distribution and habitat
Brown Bear at Brooks Falls Brown bears were once native to Asia, the Atlas Mountains in Africa, Europe and North America,[6] but are now extinct in some areas and their populations have greatly decreased in other areas. They prefer semi-open country, usually in mountainous areas. Brown bears live in Alaska, east through the Yukon and Northwest Territories, south through British Columbia and through the western half of Alberta. Small populations exist in the Greater Yellowstone Ecosystem of northwest Wyoming (with about 600 animals), the Northern Continental Divide Ecosystem of northwest Montana (with about 400-500 animals), the Cabinet-Yaak Ecosystem of northwest Montana and northeast Idaho (with about 30-40 animals), the Selkirk Ecosystem of northeast Washington and northwest Idaho (with about 40-50 animals), and the North Cascades Ecosystem of north-central Washington (with about 5-10 animals). These five ecosystems combine for a total of roughly 1,200 wild grizzlies still persisting in the contiguous United States. Unfortunately, these populations are isolated from each other, inhibiting any genetic flow to occur between ecosystems. This poses one of the greatest threats to the future survival of the grizzly bear in the contiguous United States. The population of brown bears in the Pyrenees mountain range between France and Spain is so low, estimated at fourteen to eighteen with a shortage of females, that bears, mostly female, from Slovenia were released in the spring of 2006 to alleviate the imbalance and preserve the species' presence in the area, despite protests from French farmers. In Arctic areas, the potential habitat of the brown bear is increasing. The warming of that region has allowed the species to move farther and farther north into what was once exclusively the domain of the polar bear. In non-Arctic areas, habitat loss is blamed as the leading cause of endangerment, followed by hunting. North American brown bears seem to prefer open landscapes, whereas in Eurasia they inhabit mostly dense forests. It is thought that the Eurasian bears which colonized America were tundra adapted, something indicated by brown bears in the Chukotka Peninsula on the Asian side of Bering Strait, which are the only Asian brown bears to live year-round in lowland tundra like their American cousins.[7] Brown bear in prehistoryNorth AmericaThe brown bear has existed in North America since at least the most recent ice age, though it is thought that the larger, taller, and stronger giant short-faced bear or bulldog bear was the dominant carnivore at the time. The giant short-faced bear was a tall, thin animal adapted to eating large mammals, whereas the grizzly or brown bear has teeth appropriate for its omnivorous diet. The brown bear also shared North America with the American lion and Smilodon, carnivorous competitors. The modern grizzly can eat plants, insects, carrion, and small and large animals. The American lion, Smilodon, and giant short-faced bear had a more limited range of food, making them vulnerable to starvation as the supply of available large mammals decreased, possibly due to hunting by humans. The time of the Arctodus extinction is about the same as that of the long-horned Bison and other megafauna. Both of these animals were replaced by Eurasian immigrants, specifically the Brown Bear and American Bison. Since this was also about the same time as the Clovis tool kit hunting culture appeared in North America, with culturally advanced humans entering the Americas from Asia, the implication is that the brown bear was better adapted to human competition than the megafauna, presumably due to a long term coexistence in the Old World with people. The extinction of ice-age herbivorous megafauna resulted in the extinction of the sabertooth, American lion, and giant short-faced bear, leaving the brown bear as the major large predator in North America, with the gray wolf, the jaguar in the south, the American black bear, and cougar also competing for large prey. The origin of human presence in America is widely accepted to have occurred across the Bering Land Bridge with the largest known immigration being that of the Paleo Indians at about the last ice age, bringing with them the Clovis point and advanced hunting techniques (see: Migration to the New World). When the last ice age ended about 10,000 years ago, brown bears from farther south in North America slowly expanded their range northward and back up into Alaska. Today there are three genetically distinct grizzly bear clades in North America: the Alaskan-Yukon Grizzly, the Alberta-Saskatchewan lineage, and those found in the Colorado-Washington-Idaho-Montana-Wyoming area. EurasiaIn Europe, the brown bear shared its habitat with other predators such as the Cave lion, Cave hyena and the larger, closely related Cave bear, which the brown bear ultimately outlasted. The cave bear was hunted by Neanderthals who may have had a religion relating to this bear, the Cave Bear Cult, but the Neanderthal population was too small for their consumption of cave bear to result in the species' extinction, and the cave bear outlasted the Neanderthals by 18,000 years, becoming extinct about 10,000 years ago. The cave bear and brown bear diets were similar, and the two species probably lived in the same area at the same time. Why the cave bear died out is not known. The Caledonian bear was said to be so fierce that it was favoured by the Romans who used them in their amphitheatres. BehaviorThe brown bear is primarily nocturnal and, in the summer, puts on up to 180 kg (400 pounds) of fat, on which it relies to make it through winter, when it becomes very lethargic. Although they are not full hibernators, and can be woken easily, both sexes like to den in a protected spot such as a cave, crevice, or hollow log during the winter months. Brown bear are mostly solitary, although they may gather in large numbers at major food sources and form social hierarchies based on age and size.[8] awsomeer Dietary habits
Brown bear feeding on salmon Interspecific predatory relationshipsBrown bears will often use their large size to intimidate wolves from their kills. In Yellowstone National Park, brown bears pirate wolf kills so often that Yellowstone?s Wolf Project Director Doug Smith once wrote: "It?s not a matter of if the bears will come calling after a kill, but when." Though conflict over carcasses is common, the two predators will on some rare occasions tolerate each other on the same kill. Both species will prey on each others cubs, given the opportunity. [11] Adults bears are generally immune from predatory attacks from anything other than another bear. Some bears emerging from hibernation will seek out tigers in order to steal their kills. [12] However, in the Russian Far East brown bears, along with smaller Asiatic black bears constitute 5-8% of the diet of Siberian tigers.[13] In particular, the brown bear's input is estimated as 1-1,5%.[14] However, for the tiger, even bears of the same size are a force to be reckoned with when confronted head on. Adult Brown Bears are known for killing and driving off Adult Male Tigers. [14] There is an opinion that the brown bear/tiger conflict can eliminate the weakest animals from both populations.Brown bears usually dominate other bear species in areas where they coexist. Due to their smaller size, American black bears are at a competitive disadvantage over brown bears in open, non-forested areas. Although displacement of black bears by brown bears has been documented, actual interspecific killing of black bears by brown bears has only occasionally been reported. The diurnal black bear's habit of living in heavily forested areas as opposed to the largely nocturnal brown bear's preference for open spaces usually ensures that the two species avoid confrontations in areas where they are sympatric.[15] There has been a recent increase in interactions between brown bears and polar bears, theorized to be caused by global warming. Brown bears have been seen moving increasingly northward into territories formerly claimed by polar bears. Brown bears tend to dominate polar bears in disputes over carcasses[16], and dead polar bear cubs have been found in brown bear dens.[17] Giant Panda cubs have also been reportedly eaten by brown bears.[1] Habituation to human areasBears become attracted to human created food sources such as garbage dumps, litter bins, and dumpsters; and venture into human dwellings or barns in search of food as humans encroach into bear habitat. In the U.S., bears sometimes kill and eat farm animals. When bears come to associate human activity with a "food reward", a bear is likely to continue to become emboldened and the likeliness of human-bear encounters increases, as they may return to the same location despite relocation. The saying, "a fed bear is a dead bear," has come into use to popularize the idea that allowing bears to scavenge human garbage, such as trash cans and campers' backpacks, pet food, or other food sources that draw the bear into contact with humans can result in a bear's death.Relocation has been used to separate the bear from the human environment, but it does not address the problem bear's newly learned humans-as-food-source behavior. Nor does it address the environmental situations which created the human habituated bear. "Placing a bear in habitat used by other bears may lead to competition and social conflict, and result in the injury or death of the less dominant bear."[18] Yellowstone National Park, an enormous reserve located in the Western United States, contains prime habitat for the Grizzly Bear (Ursus arctos horribilis), but due to the enormous number of visitors, human-bear encounters are common. The scenic beauty of the area has led to an influx of people moving into the area. In addition, because there are so many bear relocations to the same remote areas of Yellowstone, and because male bears tend to dominate the center of the relocation zone, female bears tend to be pushed to the boundaries of the region and beyond. The result is that a large proportion of repeat offenders, bears that are killed for public safety, are females. This creates a further depressive effect on an already endangered species. The grizzly bear is officially described as threatened in the U.S. Though the problem is most significant with regard to grizzlies, these issues affect the other types of brown bear as well. In Europe, part of the problem lies with shepherds; over the past two centuries, many sheep and goat herders have gradually abandoned the more traditional practice of using dogs to guard flocks, which have concurrently grown larger. Typically they allow the herds to graze freely over sizeable tracts of land. As bears reclaim parts of their range, they may eat livestock. In some cases, the shepherd will shoot the bear thinking that his livelihood is under threat. Many are now better informed about the ample compensation available and will make a claim when a loss to his livestock due to a bear takes place. brown bears are lovly from c There is little agreement on classification of brown bears. Some systems have proposed as many as 90 sub-species while recent DNA analysis has identified as few as five clades.[19] DNA analysis has 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.[20] The subspecies of brown bears have been listed as follows: one of which (called clade I by Waits, et al., part of the subspecies identified as U. a. sitkensis, by Hall and U. a. dalli by Kurtén) appears to be more closely related to the polar bear than to other brown bears.[20]
HybridsA grizzly?polar bear hybrid is a rare ursid hybrid resulting from a union of a brown bear and a polar bear. It has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA of a strange-looking bear that had been shot in the Canadian arctic.[21] Previously, the hybrid had been produced in zoos and was considered a "cryptid" (a hypothesized animal for which there is no scientific proof of existence in the wild).Legal status
Bear encountersThere are an average of two fatal attacks a year in North America.[23] In Scandinavia, there are only four known cases since 1902 of bear encounters which have resulted in death. The two most common causes for bear attack are surprise and curiosity.[24] Some types of bears, such as polar bears, are more likely to attack humans when searching for food, while American black bears are much less likely to attack. The Alaska Science Center ranks the following as the most likely reasons for bear attacks:[24]
History of bear defenseBecause of the unreliability of pepper spray, guns have been the preferred method of defense from bears.[25] Too often people do not carry a proper caliber weapon to neutralize the bear. According to the Alaska Science Center, a 12 gauge shotgun with slugs has been the most effective weapon. There have been fewer injuries as a result of only carrying lethal loads in the shotgun, as opposed to deterrent rounds. State of Alaska Defense of Life or Property (DLP) laws require you to report the kill to authorities, and salvage the hide, skull and claws.[26] If a bear is killed near camp the bear?s carcass must be adequately disposed of, including entrails and blood if possible. Failure to move the carcass has often resulted in it attracting other bears and further exacerbating a bad situation.[25] See also
External links
References
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