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Brown Bear Characteristics & Behavior

Color of brown bears

Brown bears are often not brown. 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 centimeters (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.

Large claws for digging

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 centimeters (2.0 to 2.4 in) and sometimes 7 to 10 centimeters (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 (Ursus americanus). The claws are blunt, while those of a black bear are sharp. Due to their claw structure, in addition to their excessive weight, adult brown bears cannot climb trees as can both species of black bear. The paws of the brown bear are quite large. The rear feet of adult bears have been found to typically measure 21 to 36 cm (8.3 to 14.2 in) long, with huge Kodiak bears having measured up to 46 cm (18 in) along their rear foot.

Body size

The size of brown bears is the most variable of modern bears. The typical size depends upon which population it is from. A large barren ground brown bear might seem quite small elsewhere.

The brown bear (grizzly bear in Europe, Yellowstone National Park or interior Alaska) seasonally weigh on average between 115 and 360 kg (254 and 794 lb). Bears from the Yukon Delta, interior British Columbia, Jasper National Park and southern Europe can weigh from 55 to 155 kg (121 to 342 lb) on average. Bears from the Syrian (U. a. syriacus) and the Gobi Desert (U. a. gobiensis) subspecies are around the same mass as the smaller Eurasian brown and grizzly bears and can exceptionally measure as small as 1 m (3.3 ft) in head-and-body length. On the other end of the scale among 2 interior brown bears, exceptional grizzly, Eurasian brown bears, and East Siberian brown bears (U. a. collaris) have been weighed up to 680 kg (1,500 lb), 481 kg (1,060 lb) and 600 kg (1,300 lb), respectively.

Interior brown bears are generally smaller than is often perceived, being around the same weight as an average African lion at an estimate average of 180 kg (400 lb) in males and 135 kg (298 lb) in females.

The largest inland brown bear subspecies appears to be the Ussuri brown bear (U. a. lasiotus), likely the ancestor of the modern-day American grizzly, which can obtain sizes comparable to those of the coastal bears as described below.

Due to the lack of genetic variation within subspecies, the environmental conditions in a given area likely plays the largest part in such weight variations.

The largest subspecies, the Kodiak bear (U. a. middendorffi), rivals the polar bear as the largest member of the bear family (Ursidae). The Ussuri brown bear and also the extinct California grizzly approached the Kodiak brown bear in size. Leopold (1959) described the Mexican grizzly that, according to Rausch (1963), qualifies as the smallest form of U. a. horribilis in North America. One California grizzly weighed 2,200 lb (1,000 kg) pounds.

Size fluctuates depending upon sex, age, individual, geographic location, and season. The normal range of physical dimensions for a brown bear is a head-and-body length of 1.4 to 2.8 m (4.6 to 9.2 ft) and a shoulder height of 70 to 153 cm (28 to 60 in). Males within one area are larger than females, typically weighing around 30% more.

The tail is relatively short, ranging from 6 to 22 cm (2.4 to 8.7 in) in length. Adult bears generally weigh between 100 and 635 kg (220 and 1,400 lb). Generally speaking, brown bears weigh the least when they emerge from hibernation in the spring and then reach peak weights when preparing for hibernation in the fall (when they often gorge on large food stuffs).

Behavior

Although the brown bear is primarily nocturnal, it is frequently seen in morning and early evening hours. In summer through autumn, it can double its weight, gaining up to 180 kg (400 lb) 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 bears are mostly solitary, although they may gather in large numbers at major food sources (e.g., moth colonies, open garbage dumps or rivers holding spawning salmon) and form social hierarchies based on age and size. 3

Adult male bears are particularly aggressive and are avoided by adolescent and subadult males. Female bears with cubs rival adult males in aggression, and are more intolerant of other bears than single females. Young adolescent males tend to be least aggressive, and have been observed in nonantagonistic interactions with each other. Dominance between bears is asserted by making a frontal orientation, showing off canines, muzzle twisting and neck stretching to which a subordinate will respond with a lateral orientation, by turning away and dropping the head and by sitting or lying down. During combat, bears use their paws to strike their opponents in the chest or shoulders and bite the head or neck. In his Great Bear Almanac, Gary Brown lists 11 different sounds bears produce in 9 different contexts. Sounds expressing anger or aggravation include growls, roars, woofs, champs and smacks, while sounds expressing nervousness or pain include woofs, grunts, and bawls. Sows will bleat or hum when communicating with their cubs.

Modified article from: https://en.wikipedia.org/wiki/Brown_bear License: http://creativecommons.org/licenses/by-sa/3.0/ Date: 03/09/16