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Brown Bear

From Wikipedia, the free encyclopedia

 

Brown Bear

Brown Bear rearing

Scientific classification

Kingdom:

Animalia

Phylum:

Chordata

Class:

Mammalia

Order:

Carnivora

Family:

Ursidae

Genus:

Ursus

Species:

U. arctos

Binomial name

Ursus arctos
Linnaeus, 1758

Ursus arctos range map.

 

The brown bear (Ursus arctos) is a species of bear distributed throughout the Northern hemisphere. Weighing up to 130–700 kg (290-1,550 pounds), the larger races of brown bear tie with the Polar bear as the largest extant land carnivores. The grizzly bear (Ursus arctos horribilis), the Kodiak Bear (Ursus arctos middendorffi), and the Mexican brown bear are North American subspecies of the brown bear. However, 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.[2] It is sometimes referred to poetically as the bruin.

 

 

Characteristics

Appearance

Brown Bears have furry coats in shades of blonde, brown, black, or a combination of those colors. The longer outer guard hairs of the brown bear are often tipped with white or silver, giving a "grizzled" appearance. Brown bears have a large hump of muscle over their shoulders, which give strength to the forelimbs for digging. Bears are very powerful, even if considered pound for pound, a big specimen can break a neck or spine of a fully grown buffalo with a single blow. Forearms end in massive paws with very powerful claws up to 15 cm (5.9 inches) in length. Their heads are large and round with a concave facial profile. 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 90 to 150 cm (35 to 59 inches), although the abnormally large specimens exceed these measurements. The smallest subspecies is the European brown bear, with mature females weighing as little as 90 kg (200 lb). The largest subspecies of the brown bear are the Kodiak bear and the bears from coastal Russia and Alaska. Some large male Kodiak are over 3m (10 feet) in height while on their hind legs, and weigh about 680 kg (1,500 lb). Bears raised in zoos are usually heavier than bears raised in the wild because of regular feeding and less movement. In zoos, bears may weigh up to 900 kilograms (2000 pounds), like the well-known "Goliath" from New Jersey's Space Farms zoo. They have a very short, stubby tail, just like all bears.

 

Digging and hunting

Claws are mainly used for digging. Unlike the claws of other large predatory animals such as lions or tigers, brown bear claws are not retractable, giving them a dull edge compared to the claws of other predators. When hunting, the brown bear uses its sharp canine teeth for neck-biting its prey. Brown bears, like tigers, ambush their prey.

 

Speed

In spite of their size, some have been clocked at speeds in excess of 56 km/h (35 mph). Along with their strength and deceptive speed, brown bears are legendary for their stamina. They are capable of running at full speed for miles at a time without stopping.

 

Habitat

Brown bears were once native to Asia, the Atlas Mountains in Africa, Europe and North America,[3] 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. Isolated populations exist in northwestern Washington, northern Idaho, western Montana, and northwestern Wyoming. Ursus arctos 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, also known as the bulldog bear, was the dominant carnivore at the time. The giant short-faced bear was a tall, thin animal adapted to eat large mammals, whereas the grizzly or brown bear has teeth appropriate for its omnivorous diet. The giant short-faced bear, on average, weighed twice as much as the grizzly, despite some exceptional grizzly bears in the later Old West that weighed 800 kilograms.

Ursus arctos 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 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 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 a human presence in America in unknown, but largest known immigration was that of the Paleo Indians at about the last ice age, bringing with them the Clovis point and advanced hunting techniques.

In Europe, the brown bear outlasted the larger and closely related cave bear. 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 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.

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. Much smaller populations, ranging in the hundreds, are also present in countries such as Mexico. In Europe, there are 14,000 brown bears in ten separate fragmented populations, from Spain to Russia and from Scandinavia in the north to Romania and Bulgaria in the south. They are extinct in the British Isles, extremely threatened or extinct in France, 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.

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.

Brown bears prefer semi-open country, usually in mountainous areas.

 

Behavior

The 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.

 

Eating

They are omnivores and feed on a variety of plant parts, including berries, roots, and sprouts, fungi, fish, insects, and small mammals, especially ground squirrels. Contrary to popular mythology, brown bears are not particularly carnivorous as they derive up to 90% of their dietary food energy from vegetable matter.[citation needed] Their jaw structure has evolved to fit their dietary habits and it is longer and lacks strong, sharp canine teeth of true predators. Bears eat an enormous number of moths during the summer, sometimes as many as 40,000 in a day[1], and may derive up to a third of their food energy from these insects[2]. Locally, in areas of Russia and Alaska, brown bears feed mostly on spawning salmon, and the nutrition and abundance of this food accounts for the enormous size of the bears from these areas. Brown bears also occasionally prey on deer (Odocoeilus spp.; Dama spp., Capreolus spp.), Red Deer (Cervus elaphus or American elk), moose (Alces alces) and American bison (Bison bison). When brown bears attack these animals, they tend to choose young calves or aged, sick adults because they are slow and weak. Brown bears retrace their own tracks and walk only on rocks while being hunted to avoid being traced.

 

Posture

The brown bear is plantigrade like all bears, meaning it walks with its entire foot like a human, rather than on its toes like cats and dogs, which are digitigrade. They can stand up on their hind legs for extended periods of time. Bears tend to sit down on their rear with their upper body off the ground.

Normally a solitary animal, the brown bear congregates alongside streams and rivers during the salmon spawn in the fall. Every other year, females produce one to four young, which weigh only about 1 to 2 kg (2 to 5 lb) at birth. Raised entirely by their mother, cubs are taught to climb trees when in danger. Brown bears are also found in the midwest region of the U.S. in the states of Montana, Wyoming, Minnesota, Wisconsin,and Idaho.

 

Habituation to human areas

Bears 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. The saying, "a fed bear is a dead bear," has come into use to popularize the idea that allowing bears to scavenge human garbage, 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."[4]

Some bears become hooked on a given food source and will return to the same location despite relocation. Bears that repeatedly return to a human environment for food are sometimes killed to prevent human injury.

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 take livestock as a means of survival. The shepherd is forced to shoot the bear to protect his livelihood.

 

Subspecies

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. The subspecies of brown bears have been listed as follows:[5] 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.[2]

 

Legal status

 

Bear encounters

It is extremely rare that brown bears kill or seriously injure humans, but fatal encounters occur when brown bears behave aggressively. There are an average of two fatal attacks a year in North America.[6] In Scandinavia, there are only three known cases during the last 100 years in which humans were killed by bears. Attacks usually occur because the bear is injured or a human encounters a mother bear with cubs. 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 Scandinavian Bear Research project lists the following situations as potentially dangerous:

1.     Meeting an injured bear

2.     A human suddenly appearing

3.     Meeting a bear in its cave

4.     Meeting a bear who has been provoked

Anyone walking in a forest where there are bears should carry an air horn because 'bear bells' tend to provoke a bear's curiosity and a brown bear's natural instinct is to run away from humans. When traveling in groups, trail songs are also effective. If camping, do not bring food into the tent, and clean up all garbage. Bears have a fantastic sense of smell and will eat anything people eat. If one meets a bear, one should remain calm and slowly walk in the opposite direction. Running humans trigger the bear's chasing instinct and bears can outrun humans. Do not make threatening moves, eye contact, or shout. Thousands of encounters occur between humans and brown bears every year without conflict.

If a brown bear attacks and it is impossible to get away, the person should lie down in a fetal position and put his/her hands around the head to protect from bites to reduce damage to vital organs. Pretending to be dead may save you. Unlike with the American black bear, punching or gouging attacking brown bears intensifies their assaults. [citation needed] Black bears are NOT the same as Grizzlies. Don't confuse the two.

[edit] Other bear encounters

American black bears, rarely attack and are almost totally vegetarian, but require a different technique. For these, people should huddle if in a group or raise hands or backpack in the air to appear bigger, as well as make lots of noise. There is a good chance of scaring away a black bear as they are shy and timid. If it attacks anyway, fight back. Black bears will disengage if injured. However, the best defense is to make plenty of noise in areas with bears to scare them away before an encounter.

 

Firearms for defense

In some areas, it is permissible to carry firearms to defend against bear attacks. This includes most of the state of Alaska and the Canadian bush. In parts of northern Canada, a rifle of sufficient power is required equipment. The Alaska Department of Fish and Game recommends as a minimum firearm for use against brown bear a rifle in the .30-06 range firing 200 grain expanding bullets moving at least 2,000 feet per second (610 m/s) at impact. Many Alaskan hikers prefer using shotguns firing a Brenneke slug at magnum velocities or lever-action rifles able to fire magnum-level .45-70 cartridges. These firearms are lighter and easier to tote than a full-size bolt-action hunting rifle, but can fire heavy hardcast slugs which impact with 3,000 ft·lbf or more at close range. They are less effective in hunting brown bears due to limited effective range, but for purposes of defense that is not of paramount concern.

It is also important to remember that the considerations while hunting a brown bear are different from those which arise while defending against an attacking brown bear. Hunters will wait for a broadside shot at the heart/lung area of unsuspecting bears. With proper placement, almost any rifle is capable of taking out a brown bear in these circumstances. Though it is not recommended and may be illegal under current game rules, historically the .30-30 and even .32-20 were used to hunt brown bears. However, when the bear is charging, a round of substantially more power is preferred to both disable the animal quickly and penetrate the thick layers of bone, fat, and tissue between the bear's head and shoulders and its vital organs. Hitting the brain is notoriously difficult due to its placement deep below a muscular brow.

In the past decade, a number of high-powered handguns have been produced in the United States for use in handgun hunting and bear defense. These include the .454 Casull revolvers produced by Taurus and Ruger and the .500 Smith & Wesson produced for that company's supersized "X" frame revolver. Their enormous recoil and weight make them difficult to deploy quickly in the field. Their utility in defense against brown bears is still a matter of great controversy.

A number of pepper sprays have recently been developed as non-lethal (but very harmful) and potentially safer defense against bear attacks. Pepper spray is deployed in the same manner one would deploy a can of mace; an effective shot is one to the face. Pepper spray is not used like insect repellant; spraying campsites with pepper spray seems to attract bears.

 

 

Wikipedia

 

http://en.wikipedia.org/w/index.php?title=Brown_Bear&action=history

 

http://www.gnu.org/copyleft/fdl.html