The North American bison, also known as the buffalo, is a very large animal, with a shaggy dark-coloured mane covering its head, shoulders and forelegs. It has a hump at the shoulders and a long tail with a hairy tuft or tassel at the end. Its extremely thick coat keeps it warm during the deep-freeze of winter, and as summer approaches, it sheds its coat to keep cool.
Short, curved black horns stick out from the bison’s head, just above the eyes. The horns are used to defend itself against predators. A bison’s eyesight is poor, but its hearing and sense of smell are very good.
The male bison, or bull, has a large, square-shaped neck, while the female, referred to as a bison cow, has a smaller, rounder neck. There are two subspecies of bison in North America: the plains bison and the wood bison. The plains bison is not as dark or tall as the wood bison and has a smaller hump, a much more pronounced beard and a thicker mane in general. While the wood bison isn’t as stocky as the plains bison, it is heavier.
Habitat and behaviour
The bison is found in prairies and open forests with meadows. It feeds mainly on grass and other plants and occasionally on berries. Finding food in winter isn’t a problem for the bison. Swinging its massive head from side to side, it pushes away the snow cover to get to the grass below. It is mostly active at dusk and night.
Despite its size, the bison is able to run at speeds of up to 55 kilometres per hour. It is also an excellent swimmer and is so buoyant that its head, hump and tail stay above the surface of the water.
Herd animals, bison usually form groups consisting of cows, calves, yearlings, subadults and a few bulls. The remaining bulls form their own group. Mating takes place from July to mid-September, and the roaring sounds made when the bulls challenge one another can often be heard for kilometres.
Their herding behaviour can sometimes get the bison into trouble. When a large group gathers on the ice in spring, for instance, the ice can break up under their weight, causing many to drown. However, their instinct to move into the wind during a blizzard saves them from being crushed against fences by snowdrifts, as cattle sometimes are.
Bison roll in depressions, or wallows, in the ground to cover themselves in dust or mud as protection against biting insects. When a large number of bison roll in the same area, huge wallows are formed. These sometimes fill with water, creating new habitats for other animals, such as frogs and ducks.
Bison once roamed by the millions across the prairies, but populations were decimated due to overhunting by European settlers in the 19th century, and they now exist in much smaller groups. Plains bison range throughout several national parks in western Canada, such as Elk Island National Park, near Edmonton, and Riding Mountain National Park, northwest of Winnipeg. They are also found in national and state parks in the United States and in private collections, and approximately 700,000 are farmed on commercial ranches in Canada and the United States. Only about 1,000 free-roaming or semi-free-roaming bison exist in Canada.
Wood bison have always been fewer in number than plains bison and range farther north. A large herd of free-roaming wood bison lives in the Mackenzie Bison Sanctuary, near Fort Providence, N.W.T. Another free-roaming herd of both wood and plains bison is in Wood Buffalo National Park, straddling the border between the Northwest Territories and Alberta. Bison are also found in British Columbia and the Yukon, and just over 10,000 exist in free-ranging and captive research herds.
Bison are hunted by grizzly bears, grey wolves and cougars. Humans hunt them too, but under strict regulations and only in designated areas.