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Brown Bear
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The Brown Bear (Ursus arctos) is a large bear distributed across much of northern Eurasia and North America. It weighs 100 to 700 kg (220-1,500 pounds) and its larger populations such as the Kodiak bear match the Polar bear as the largest extant land predator.
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.
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The Brown Bear (Ursus arctos) is a large bear distributed across much of northern Eurasia and North America. It weighs 100 to 700 kg (220-1,500 pounds) and its larger populations such as the Kodiak bear match the Polar bear as the largest extant land predator.
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. It also eats small land mammals and occasionally larger mammals, such as deer. Adult brown bears 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.
Taxonomy
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. 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. One subspecies appears to be more closely related to the polar bear than to other brown bears. This species is called "clade I" by Waits, et al., and is part of the subspecies identified as U. a. sitkensis, by Hall and as U. a. dalli by Kurtén. The subspecies have been listed as follows:
* Ursus arctos lasiotus – Amur brown bear ( or "Ussuri brown bear", "black grizzly" or "horse bear"), Russia: Southern Kuril Islands, Sakhalin, Maritime Territory, and the Ussuri/Amur river region south of the Stanovoy Range. China: Northeastern Heilongjiang. Japan: Hokkaido
Ursus arctos marsicanus – Marsican Brown Bear; Central Italy (critically endangered) Ursus arctos meridionalis – Northern Caucasus Ursus arctos middendorffi – Kodiak Bear; Kodiak, Afognak, Shuyak Islands (Alaska) Ursus arctos nelsoni – Mexican Grizzly Bear; (extinct) Ursus arctos collaris – Siberian Brown Bear; Siberia (except for the habitat of the Kamchatka and Amur brown bears.) Also in northern Mongolia, far northern Xinjiang, and extreme eastern Kazakhstan. Ursus arctos pruinosus – Tibetan Blue Bear; Western China Ursus arctos syriacus – Syrian Brown Bear; Middle East Ursus arctos yesoensis – Hokkaido Brown Bear; Japan Ursus arctos piscator – Bergman's Bear (extinct?)
Hybrids
A 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. 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).
Description
Brown bears have furry coats in shades of blonde, brown, black, or a combination of those colors. The longer outer guard hairs are often tipped with white or silver, giving a "grizzled" appearance. Their tail is 4-5 inches (10-13 cm) long. Like all bears, brown bears are plantigrades and can stand up on their hind legs for extended periods of time. Brown bears have a large hump of muscle over their shoulders which distinguishes them from other species. Brown bears are very powerful, and can break the backs and necks of large prey. The forearms end in massive paws with claws up to 15 cm (6 inches) in length which are mainly used for digging. The claws are not retractable, and have relatively blunt points. Their heads are large and round with a concave facial profile, a characteristic used to distinguish them from other bears. Males are 38-50% larger than females.
The normal range of physical dimensions for a brown bear is a head-and-body length of 1.7 to 2.8 m (5.6 to 9.2 feet) and a shoulder height of 90 to 150 cm (35 to 60 inches). 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 (331 lb). The largest subspecies are the Kodiak bear, Siberian Brown Bear, and the bears from coastal Russia and Alaska. It is not unusual for large male Kodiak Bears to stand over 3 m (10 feet) while on their hind legs, and to weigh up to 680 kg (1,500 lb). The largest wild Kodiak bear on record weighed over 1,100 kilograms (2400 pounds). Bears raised in zoos are often heavier than wild bears because of regular feeding and limited movement. In zoos, bears may weigh up to 900 kilograms (2,000 pounds), one example being "Goliath" from New Jersey's Space Farms Zoo and Museum. Size seems related to food availability, and subspecies distinctions is more related to nutrition than geographical location.
Despite their size, some brown bears have been clocked at speeds in excess of 64 km/h (40 mph).
Distribution and habitat
There are about 200,000 brown bears in the world. The largest populations are in Russia, with 120,000, the United States with 32,500, and Canada with 21,750. 95% of the brown bear population in the United States is in Alaska, though in the West they are repopulating slowly but steadily along the Rockies and plains. Although many people hold on to the belief that some brown bears may be present in Mexico and the Atlas Mountains of Morocco, both are almost certainly extinct. The last Mexican brown bear was shot in 1960. In Europe, there are 14,000 brown bears in ten fragmented populations, from Spain in the west, to Russia in the east, and from Scandinavia in the north to Romania, Bulgaria, Slovakia (with about 800 - 900 animals) and Greece (with about 200 animals) in the south. They are extinct in the British Isles, extremely threatened in France and Spain, and in trouble over most of Central Europe. The brown bear is Finland's national animal. The Carpathian brown bear population is the largest in Europe outside Russia, estimated at 4,500 to 5,000 bears.
Brown bears were once native to Asia, the Atlas Mountains in Africa, Europe and North America, 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 14 to 18 with a shortage of females, that bears, mostly female, from Slovenia were released in spring 2006 to reduce 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 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. This is 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.
Behavior
The brown bear is primarily nocturnal. In the summer it gains 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.
Reproduction
The mating season is from late May to early July. Being serially monogamous, brown bears remain with the same mate from several days to a couple of weeks. Females mature sexually between the age of 5 and 7 years, while males usually mate a few years later when they are large and strong enough to successfully compete with other males for mating rights.
Through the process of delayed implantation, a female's fertilized egg divides and floats free in the uterus for six months. During winter dormancy, the fetus attaches to the uterine wall. The cubs are born eight weeks later, while the mother sleeps. If the mother does not gain enough weight to survive through the winter, the embryo does not implant and is reabsorbed into the body. The average litter has one to four cubs, usually two. There have been cases of bears with five cubs, though sometimes females adopt strange cubs. Older females tend to give birth to larger litters. The size of a litter also depends on factors such as geographic location and food supply. At birth, the cubs are blind, toothless, hairless and weigh less than 1 pound. They feed on their mother’s milk until spring or even early summer depending on climate conditions. At this time, the cubs weigh 15 to 20 pounds and have developed enough to follow her and begin to forage for solid food.
Cubs remain with their mother from two to four years, during which time they learn survival techniques, such as which foods have the highest nutritional values and where to attain them, how to hunt, fish, and defend themselves, and where to den. The cubs learn by following and imitating their mother’s actions during the period they are with her. Brown bears practice infanticide. An adult male bear may kill the cubs of another bear either to make the female sexually receptive or simply for consumption. Cubs flee up a tree when they see a strange male bear, and the mother defends them even though the male may be twice her size.
Dietary habits
They are omnivores and feed on a variety of plant products, including berries, roots, and sprouts, fungi as well as meat products such as fish, insects, and small mammals. Despite their reputation, most brown bears are not particularly carnivorous as they derive up to 90% of their dietary food energy from vegetable matter. Their jaw structure has evolved to fit their dietary habits. Their diet varies enormously throughout their differing ranges. For example, bears in Yellowstone eat an enormous number of moths during the summer, sometimes as many as 40,000 in a day, and may derive up to half of their annual food energy from these insects. In some areas of Russia and Alaska, brown bears feed mostly on spawning salmon, whose nutrition and abundance explains the enormous size of the bears in these areas. Brown bears also occasionally prey on deer, elk, moose, caribou, and bison. When brown bears attack these animals, they tend to choose the young ones because they are much easier to catch. When hunting, the brown bear uses its sharp canine teeth for neck-biting its prey. On rare occasions, bears kill by hitting their prey with their powerful forearms which can break the necks and backs of large prey, such as bison. They also feed on carrion and use their size to intimidate other predators such as wolves, cougars, tigers and black bears from their kills.
Interspecific predatory relationships
Brown bears often use their large size to scare wolves away from their kills. In Yellowstone National Park, brown bears pirate wolf kills so often that Yellowstone’s Wolf Project Director Doug Smith wrote: "It’s not a matter of if the bears will come calling after a kill, but when." Though conflict over carcasses is common, on rare occasions the two predators tolerate each other on the same kill. Given the opportunity, both species prey on each other's cubs.
Adult 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. However, in the Russian Far East brown bears, along with smaller Asiatic black bears constitute 5-8% of the diet of Siberian tigers. However, Brown Bears are also known to drive Adult Siberian Tigers off kills and killing them.
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. Confrontation is mostly avoided thanks to the black bear's diurnal habit and preference for heavily forested areas, as opposed to the brown bear's largely nocturnal habit and preference for open spaces.
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, and dead polar bear cubs have been found in brown bear dens. Giant Panda cubs have also been reportedly eaten by brown bears.
Brown bears may also compete with cougars for prey. Brown bears have been reported to kill cougars in the American west. Cougars are better hunters than grizzly bears but weaker fighters and therefor a potential target for a hungry grizzly. Cougars may try to scare bears off by making loud noises and it does work on occasions.
Relationship with humans
Bears become attracted to human-created food sources such as garbage dumps, litter bins, and dumpsters; they 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", they are 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 of the bear has been used to separate the bear from the human environment, but it does not address the problem bear's newly learned association of humans with food. 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."
Yellowstone National Park, an enormous reserve located in the Western United States, contains prime habitat for the Grizzly Bear (Ursus arctos horribilis), and 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. As a result, 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 shepherds 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.
Legal status
- The grizzly bear, sometimes called the
silvertip bear, is listed as threatened in the Continental United States. It is slowly repopulating in areas where it was previously extirpated, though it is still vulnerable. The California golden bear (Ursus arctos californicus) disappeared from the state of California in 1922 when the last one was shot in Tulare County, but it is still on the state flag of California. The bear is alluded to in the names of the sports teams of the University of California, Berkeley (the California Golden Bears), and of the University of California, Los Angeles (the UCLA Bruins) and in the mascot of University of California, Riverside (Scottie the Bear, dressed in a Highland kilt). The Mexican grizzly bear is listed as an endangered species, but it may be extinct. In Canada, it is listed as vulnerable in Alberta, British Columbia, Northwest Territories, and Yukon Territory. Prairie populations of grizzly bear are listed as extirpated in Alberta, Manitoba, and Saskatchewan. The brown bear is a European Protected Species, given protection throughout the European Union. The brown bear is also the national animal of Finland and Slovenia.
Bear encounters
There are an average of two fatal attacks by bears per year in North America. 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. 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:
- Surprise
- Curiosity
- Invaded personal space (this includes a mother bear protecting her young)
- Predatory
- Hunting wounded
- Carcass defense
- Provoked charge
Aggressive behaviour in brown bears is favoured by numerous selection variables. Unlike the smaller black bears, adult brown bears are too large to escape danger by climbing trees, so they respond to danger by standing their ground and warding off their attackers. Increased aggressiveness also assists female brown bears in better ensuring the survival of their young to reproductive age. Mothers defending cubs are the most prone to attacking, being responsible for 70% of brown bear-caused human fatalities in North America.
History of defense from bears
Because of the unreliability of pepper spray, guns have been the preferred method of defense from bears. 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.
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.
See also
External links
- from National Geographic
- Rebuilding the European Brown Bear Population
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