The grizzly bear (Ursus arctos ssp.) is any North American subspecies of the brown bear, including the mainland grizzly (Ursus arctos horribilis), the Kodiak bear (Ursus arctos middendorffi), the peninsular grizzly (Ursus arctos gyas) and the recently extinct California grizzly (U. a. californicus) and Mexican grizzly bear (U. a. nelsoni). Specialists sometimes call the grizzly the North American brown bear because the grizzly and the brown bear are one species on two continents. In some places, the grizzly is nicknamed the silvertip bear for the silvery, grizzled sheen in its fur.
Since the mainland grizzly is so widespread, it is representative and archetypal for the whole subspecific group. Even so, classification is being revised along genetic lines. Except for females with cubs, grizzlies are normally solitary, active animals, but in coastal areas, grizzlies gather around streams, lakes, rivers, and ponds during the salmon spawn. Every other year, females (sows) produce one to four young (usually two) which are small and weigh only about 500 grams (1 lb). A sow is protective of her offspring and will attack if she thinks she or her cubs are threatened.
The word "grizzly" means "grizzled" that is, golden and grey tips of the hair. This is not to be confused with the word "grisly". Nonetheless, after careful study, naturalist George Ord formally classified the California grizzly in 1815, not for its hair, but for its character, Ursus horribilis. Thus Ord made a famous pun. Indeed there were many accounts of grizzlies fighting and beating longhorn bulls
The ancestors of the grizzly bear subspecies were brown bears originating in Eurasia that traveled to North America approximately 50,000 years ago. This is a very recent event, on an evolutionary timescale, causing the North American grizzly bear to be very similar to brown bears inhabiting Siberia and northeast Asia. The closest Eurasian subspecies to the grizzly bears are believed to be the Ussuri brown bear (U. a. lasiotus) for mainland grizzlies and the Kamchatka brown bear (U. a. beringianus) for the coastal Alaskan and Kodiak bears which arrived in North America shortly before the bering land bridge flooded.
When it received its scientific name in 1815, the grizzly was classified as a separate species from all other bears. However, modern genetic testing reveals the grizzly to be a subspecies of the brown bear (Ursus arctos). So in Eurasia, it is the "brown bear", in North America, it is the "grizzly".
In other words, the grizzly and the brown bear are one species on two continents. Currently, Rausch and others classify three subspecies of the new "North American brown bear", U. a. horribilis, middendorffi, and gyas. But more recent studies of mtDNA suggest that this three-fold division of living grizzlies needs revision. Further testing of Y-chromosomes is required to yield an accurate new taxonomy with different subspecies.
Coastal grizzlies, often referred to by the popular but geographically redundant synonym of "brown bear" or "Alaskan brown bear" are larger and darker than inland grizzlies, which is why they, too, were considered a different species from grizzlies.
Kodiak grizzly bears were also at one time considered distinct. Thus, at one time there were five different "species" of brown bear, including three in North America.
Most adult female grizzlies weigh 130–200 kg (290–440 lb), while adult males weigh on average 180–360 kg (400–790 lb). The average total length in this subspecies is 198 cm (6.50 ft), with an average shoulder height of 102 cm (3.35 ft) and hindfoot length of 28 cm (11 in). Newborn bears may weigh less than 500 grams (1.1 lb). In the Yukon River area, mature female grizzlies can weigh as little as 100 kg (220 lb). One study found that the average weight for an inland male grizzly was around 270 kilograms (600 lb) and the average weight for a coastal male was around 408 kilograms (900 lb). For a female, these average weights would be 136 kilograms (300 lb) inland and 227 kilograms (500 lb) coastal, respectively.
On the other hand, an occasional huge male grizzly has been recorded which greatly exceeds ordinary size, with weights reported up to 680 kg (1,500 lb). A large coastal male of this size may stand up to 3 metres (9.8 ft) tall on its hind legs and be up to 1.5 metres (4.9 ft) at the shoulder. Although variable from blond to nearly black, grizzly bear fur is typically brown in color with white tips. A pronounced hump appears on their shoulders; the hump is a good way to distinguish a black bear from a grizzly bear, as black bears do not have this hump.
Brown bears are found in Asia, Europe, and North America giving them one of the widest ranges of bear species. In North America, grizzly bears previously ranged from Alaska down to Mexico and as far east as the western shores of Hudson Bay. In North America, the species is now found only in Alaska, south through much of western Canada, and into portions of the northwestern United States including Idaho, Montana, Washington and Wyoming, extending as far south as Yellowstone and Grand Teton National Parks, but is most commonly found in Canada. In Canada, there are approximately 25,000 grizzly bears occupying British Columbia, Alberta, the Yukon, the Northwest Territories, Nunavut, Ontario and the northern part of Manitoba.
The Alaskan population of 30,000 individuals is the highest population of any province/state in North America. Populations in Alaska are densest along the coast, where food supplies such as salmon are more abundant. In British Columbia, grizzly bears inhabit approximately 90% of their original territory. There were approximately 25,000 grizzly bears in British Columbia when the European settlers arrived. However, population size significantly decreased due to hunting and habitat loss. In 2008, it was estimated there were 16,014 grizzly bears.