American Buffalo (Bison bison) It is believed that buffalo, or bison, crossed over a land bridge that once connected the Asian and North American continents. Through the centuries buffalo slowly moved southward, eventually reaching as far south as Mexico and as far east as the Atlantic Coast, extending south to Florida. But the largest herds were found on the plains and prairies from the Rocky Mountains east to the Mississippi River, and from Great Slave Lake in Canada to Texas.
Because the great herds were nearly gone before any organized attempts were made to survey populations, we may never know just how many buffalo once roamed North America, although estimates range from 30 to 75 million. "The moving multitude..darkened the whole plains," wrote Lewis and Clark, who encountered a herd at South Dakota's White River in 1806
By 1800, the small buffalo herds east of the Mississippi River were gone. Buffalo may have been killed to protect livestock and farmlands in that region. With westward expansion of the American frontier, systematic reduction of the plains herds began around 1830, when buffalo hunting became the chief industry of the plains.
Conservation of the buffalo came slowly. In May 1894, Congress enacted a law making buffalo hunting in Yellowstone National Park illegal. Eight years later, money was appropriated to purchase 21 buffalo from private herds to build up the Yellowstone herd. With adequate protection, this herd has steadily increased until it numbers almost 4,000 animals today.
Although the buffalo's size and color, which ranges from light to dark brown, vary in different areas of the country, experts generally agree that all American buffalo belong to the same species. The differences in appearance probably result from the variety of environments in which they live.
Like their close relatives, domestic cattle and sheep, buffalo are cloven-hoofed. Both males and females have a single set of hollow, curved horns. The male buffalo, called bulls, are immense, often weighing a ton or more and standing 5 to 6 feet high at the shoulders. The huge head and great hump covered with dark brown wooly hair contrast sharply with the relatively small hips. The females, or cows, are not as massive. Despite their great size and bulkiness, buffalo have amazing mobility, speed, and agility, and are able to sprint at speeds of up to 30 mph.
In the spring, buffalo begin to shed their heavy winter coats, and soon their hair hangs in tatters. To hasten shedding and possibly to relieve their itching skin, buffalo rub against large stones and trees. By late spring, the only remaining long hairs are on the head, forelegs, and hump. To escape the torment of attacking insects, buffalo wallow in dust or sand.
Two hundred years ago, anywhere from 30 to 70 million bison, or buffalo, roamed free in North America. The aboriginal people who lived on the Great Plains relied on these wild mammals for food, clothing, and shelter. During the late 1800s, commercial hide hunters, settlers, and thrill seekers shot literally millions of bison. This killing spree brought the species to the verge of extinction and opened up the prairies for agriculture.
Since about 1900, the population of bison in North America has increased, but not to anything near its original numbers. The great free-ranging herds have disappeared. The centuries-old migratory trails that the great beasts scored across the western grasslands have given way to freeways and farms. The wild herds that remain move freely only within parks and other wildlife sanctuaries, many of which are fenced.
Distribution and population
There are two living subspecies of wild bison in North America: the plains bison Bison bison bison and the wood bison Bison bison athabascae. The map shows the bison's present, historic, and prehistoric distribution.
Two hundred years ago, the plains bison was by far the more common of the two subspecies. It was the dominant grazing animal of the interior plains of the continent, and it often occurred in large herds. A smaller population occurred east of the Mississippi.
Today, there are comparatively few plains bison. A herd of about 600 is fenced in at Elk Island National Park, 64km east of Edmonton. There are small numbers at Prince Albert National Park in Saskatchewan, Riding Mountain National Park in Manitoba, and Waterton Lakes National Park in Alberta. There are at least 25 herds of plains bison in national and state parks and wildlife refuges in the United States, numbering more than 14,000 animals. There are more than 140,000 in private collections and on a large number of commercial ranches in both Canada and the United States.
The wood bison has always lived to the north of its prairie cousin. In historic times its range was centered in northern Alberta and the adjacent parts of British Columbia, the Northwest Territories, and Saskatchewan. Herds made use of aspen parkland, the eastern slopes of the Rocky Mountains, the lowlands of the Peace and Slave rivers, and the coniferous forests and wetland meadows of the upper Mackenzie Valley. The wood bison was never as abundant as the plains bison, probably numbering no more than 170,000 at its peak.
In April 1994, there were approximately 3000 wood bison in Canada, most in five "free-roaming" herds, the largest of which consists of more than 2000 animals in the Mackenzie Bison Sanctuary near Fort Providence, N.W.T. The source herd of 350 animals for the recovery program is at Elk Island National Park. The total population is small enough that the wood bison is considered "threatened" by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).
The other large free-roaming herd of bison is in Wood Buffalo National Park, where there are about 2000 animals, descendants of mixed plains and wood bison stock.