Bears

Grizzly Bear Ursus arctos horribilis Brown Bear, Alaskan Brown Bear, Kodiak Bear

Description

Yellowish brown to dark bown, often with white-tipped hairs, giving grizzled appearance. Hump above shoulders. Facial profile usually somewhat concave. Outer pair of incisors larger than inner 2. Claws of front feet nearly 4” (10 cm) long. Ht about 4’3” (130 cm); L 5’11”–7’ (180–213 cm); T 3” (7.6 cm); HF 10 1/4” (26 cm); Wt 324–1,499 lb (147–680 kg); some individuals to 1,700 lb (700 kg).

Endangered Status The subspecies of the Grizzly Bear that lives in the contiguous U.S. is on the U.S. Endangered Species List. It is classified as threatened in the lower 48 states, although its current range extends only into Colorado, Idaho, Montana, Washington, and Wyoming. Perhaps 50,000 Grizzlies roamed the western U.S. in 1800 from the Canadian border to Mexico, as far east as the middle of the Great Plains. The settlement and development of the West meant changes to and destruction of the Grizzly's habitat, competition with humans for game such as White-tailed Deer, and clashes between bears and humans. Grizzlies were seen as a threat to humans and livestock, and were hunted extensively both for food and fur and to eliminate them from areas where humans lived. In 1975, when the Grizzly Bear came under the protection of the U.S. Endangered Species Act, only about 1,000 remained in the lower 48 states.

Habitat degradation, from recreational development, road building, and mineral and energy exploration, remains a threat today. Even the development of areas the Grizzlies don't live in, such as valley bottoms and riverbeds, can be destructive, because the bears use these as corridors to reach suitable feeding habitat. Some private landowners and companies have volunteered to protect these corridors on their land in order to protect the bears. Plans to reintroduce Grizzlies into suitable habitat have recently been nixed by the administration of George W. Bush.

Warning All North American bears can be dangerous in the following situations: when accompanied by cubs, when surprised by the sudden appearance of humans, when approached while feeding, guarding a kill, fishing, hungry, injured, or breeding, and when familiarity has diminished their fear of humans, as in some Canadian and U.S. parks. The Grizzly is the most unpredictable and dangerous of all bears. Do not feed, approach, surprise at close range, or get between a Grizzly Bear and its food or cubs. While Grizzlies normally avoid humans, they will attack and have been known to seriously injure and even kill humans. Grizzlies can outrun humans, but adult bears lose their tree-climbing ability. If attacked, climb a tall tree or roll into a tight ball and play dead. Campers must firmly seal up food and place it out of reach. Bears will break into unattended vehicles if they smell food.

Similar Species

Black Bear is smaller, lacks shoulder hump, and has straight or slightly convex facial profile; all 3 pairs of its upper incisors are equal in size.

Breeding

Mates late June–early July; litter of 1–4 young born January–March. Newborn weighs 1 lb (450 g).

Sign Feeding signs: Shallowly dug depression and high, loose mound of branches, earth, or natural debris heaped over it may conceal cache of carrion or a kill. Beware of this sign, for a bear will not be far away. Also overturned rocks, torn-up berry patches, and raggedly torn logs. Large, gaping pits indicate that Grizzlies have dug for rodents. Trees and other signs: Girdled, bark-stripped, clawed, and bitten “bear trees,” with largest tooth marks higher than 6' (2 m) and claw slashes perhaps twice as high (marks higher than those made by Black Bears). Hair tufts on trees, which may be polished from rubbing over several seasons. Wide, deep snowslide occasionally gouged by Grizzly sliding down short incline on its haunches.

Bed: Usually in thickets, oval depression about 1’ (300 mm) deep, 3’ (900 mm) wide, 4’ (1,200 mm) long, matted with leaves, needles, or small boughs.
Scat: Usually cylindrical, often more than 2” (50 mm) wide, possibly showing animal hair, vegetation fibers, or husks. May be rounded, or massed in areas where vegetation is the primary food.
Trails: Trampled in tall grass and marked by deep depressions; may undulate.
Tracks: Shaped and placed like those of Black Bear but larger, and with long, relatively straight foreclaws farther ahead of toe pads; hindclaws register only occasionally. Hindprint of large Grizzly may be 10–12” (250–300 mm) long and 7–8” (175–200 mm) wide in front; foreprint often as wide, about half as long. In soft mud, tracks may be larger. Even on hard ground, Alaskan Brown Bears often leave bigger prints, with hind tracks more than 16” (400 mm) long, 10 1/2” (265 mm) wide, and sunk 2” (50 mm) deep. Stride averages 24” (600 mm); may be 8–9’ (2.4–2.75 m) during a bounding run.

Habitat Somewhat open country, usually in mountainous areas; also along coasts and rivers. Range Alaska, Yukon, and Northwest Territories south through most of British Columbia and w Alberta to sc Nevada.

Discussion

Primarily nocturnal, the great, shaggy Grizzly moves with a low, clumsy walk, swinging its head back and forth, but when necessary it can lope as fast as a horse. Grizzly cubs can climb, though not as nimbly as Black Bear cubs, but they lose their climbing ability during their first year. Omnivorous, the Grizzly Bear feeds on a wide variety of plant material, including roots, sprouts, leaves, berries, and fungi, as well as fish, insects, large and small mammals, and carrion. It is adept at catching fish with a swift snap of its huge jaws, and occasionally will pin a fish underwater with its forepaws, then thrust its head underwater to clasp the catch in its teeth. It digs insects from rotting logs and small mammals from their burrows, sometimes tearing up much ground in the process. It caches the remains of larger mammals, such as Elk, Moose, Mountain Goats, sheep, or livestock, returning to the cache until all meat is consumed. When salmon migrate upstream to spawn, these normally solitary bears congregate along rivers, and vicious fights may erupt among them. More often, they establish dominance through size and threats, spacing themselves out, with the largest, most aggressive individuals taking the choicest stations. In winter, Grizzlies put on a layer of fat, as much as 400 pounds (180 kg) worth, and become lethargic. They den up in a protected spot, such as a cave, crevice, dead tree, or a hollow dug out under a rock, and will return year after year to a good den. Not true hibernators, they can easily be awakened. A Grizzly in captivity has lived 47 years, but the life span in the wild is 15 to 34 years. Once regarded as a separate species, the Alaskan Brown Bear (U. a. middendorffi) is a very large subspecies of Grizzly, usually 800 to 1,200 pounds (360–545 kg) at eight or nine years of age, and eventually reaching 1,700 pounds (770 kg), making it the world’s largest terrestrial carnivore. This subspecies ranges over the coasts and islands of southern Alaska, including Kodiak Island, where it is known as the Kodiak Bear.