North America's Wild Bison:
The story of the North American Bison (Bison bison) is mysterious and tragic. Once, large herds supported the native people of the plains and nourished the first explorers and settlers. But by 1875, millions of Bison had diminished to a few hundred, mostly in captivity. Often wrongly called buffalo, the Bison is British Columbia’s largest land animal, and one of the rarest. Although the total number of Bison in North America has increased and the species is not at risk today, there are few wild herds left, and we know almost nothing about the wild Bison that originally roamed the great plains.
Bison originated in Asia and spread into North America via the Bering land bridge at least 300,000 years ago, during the middle of the Pleistocene ice age. Bison have survived at least the last two major glaciations in North America. The primitive form, known as the Steppe Bison, gave rise to several species, at least one of which had much longer horns than today's Bison and was present on the Canadian prairies as recently as 9000 years ago. One lineage gave rise to the present-day species, which emerged about the time of the latest glaciation (15,000 to 20,000 years ago) and then evolved into two races or subspecies, the Wood Bison (Bison bison athabascae) and the Plains Bison (Bison bison bison).
The Bison is easy to recognize by its large size, massive forequarters, shoulder hump, large woolly bearded head, short black horns, and moderately long tail with a tassel of dark hair. Long, shaggy, chocolatebrown hair covers the head, shoulders, and front legs, but the coppery-brown coat on the hindquarters is short. The massive build and heavy coat of the Bison's forequarters make its slim hindquarters seem out of proportion. When bulls reach adult size at about six years, they stand 1.8 m at the shoulder and weigh about 550 to 900 kg. Adult females average about 320 to 545 kg. Bulls have thicker horns than cows, with tips that curve inward more. Bulls also have a more prominent hump and bushier hair on the forehead, chin, and neck. Wood Bison are slightly larger and darker than Plains Bison. They have relatively shorter hair on their neck mane and leg chaps and a more pronounced shoulder hump than Plains Bison.
The Bison’s unusual body shape is at least partly an adaptation to the need to forage through snow, which is a constant feature of their great plains and boreal forest environment in winter. They have spines on their upper vertebrae up to 50 cm long in adult bulls. These spines support large muscles that Bison use to swing their neck and head from side to side and clear snow away from their food. Although Bison feed almost entirely on grasses and sedges that easily get covered by snow, they can exist in areas where snow cover is too deep for most other hoofed mammals (ungulates).
DISTRIBUTION BISON ANIMAL:
When European explorers arrived in North America, the Bison's range extended from the Peace River region of British Columbia and the Great Slave Lake area in the Northwest Territories all the way down to northern Mexico. In Canada they ranged eastward to Manitoba and in the United States, almost to the Atlantic coast. The Rocky Mountains marked their approximate western limit. Wood Bison occupied the boreal forest region of northeast British Columbia, northern Alberta, northwest Saskatchewan, and southwest Mackenzie Territory. The Plains Bison occupied the other parts of the Bison range.
Bison once numbered about 30 million in North America, but when settlement moved westward in the United States and Canada, they were relentlessly slaughtered. By 1800, there were no more Bison east of the Mississippi, and by 1875, the prairie herds were reduced to isolated pockets. In 1893, there were only 20 free-ranging Bison left in Yellowstone National Park and about 300 in the Wood Buffalo National Park area of northern Alberta and southern Mackenzie Territory. Since that time, numbers have increased due to the protection of wild herds, the reintroduction of Bison into former habitats, and the establishment of fenced-in herds in parks and private ranches.
The total North American Bison population now exceeds 75,000. Historically, Wood and Plains bison occupied different habitats and different geographic ranges. Along the southern edge of historic Wood Bison range (for example, the Peace River area of British Columbia) their winter ranges may have overlapped, but they probably did not share a common range during the breeding season.
There is no way of estimating the historic abundance of Wood Bison in British Columbia. The entire Canadian population probably numbered about 168,000 in the early 1800s. The population declined in the latter part of the 1800s and early 1900s, and the last confirmed naturally occurring Wood Bison was shot near Fort St. John in 1906. In the 1970s, about 50 imported Plains Bison escaped to the wild in the Pink Mountain area, and that population has grown to over 1000 head. Wood Bison have become established in northeast British Columbia as a result of reintroductions and reintroducedanimals from Mackenzie Territory and Alberta moving into the province. In 1999, there were about 80 to 100 Wood Bison in three herds in British Columbia; an additional 100 Bison occupy the Hay-Zama area in British Columbia and Alberta.