Range and Habitat
Four subspecies of bison once roamed North America from Alaska to Mexico. The pale bison (Colorado) and eastern bison (Maryland, Pennsylvania, and Virginia) are now extinct. The wood bison (Canadian woodlands) is very rare. The plains bison, which favored the grasslands, is the one displayed at the Minnesota Zoo. Before Europeans arrived in North America, bison formed what were probably the largest aggregations of large land animals on Earth—an estimated 30–60 million animals. They ranged in huge herds over most of the continent, mostly on the plains, but as far east as New York and New England, and as far south as Georgia.
These bulky relatives of domestic cattle are the largest land animals in North America. Males average 9–12 feet long and 6 feet tall at the shoulder. They usually weigh about 1 ton, but 3,000-pound bison have been recorded. Females are a bit smaller at 7–8 feet long and 5 feet at the shoulder. Both males and females have horns.
Habits and Adaptations
Bison are usually found in herds, though old bulls are often loners. Most often they are peaceful grazers, except during mating season. However, all bison are unpredictable and may attack for no apparent reason. Bison wallow or roll in mud or dust to scratch and to protect themselves from biting insects. They most often travel at a walk, but can travel very fast over rough terrain for extremely long distances. Some have been clocked at 32 mph.
Bison eat a variety of grasses and other plants. Like domestic cattle, they are ruminant (cud-chewing) animals. They have a four-chambered stomach. When they eat, the food goes to the first stomach. Later, they regurgitate the food and chew it. This allows them to eat quickly in the open where predators may be lurking, then process the food later. Bison usually feed in the morning, then lie and chew their cud during the hot afternoon hours.
Bison breed in August and September. Although most bulls reach sexual maturity at age 3, they must fight to achieve dominance before they can mate. Most dominant bulls are 4–8 years old. Cows usually begin breeding after their third year and bear a calf each year. Gestation is 9½ months, and calves are born usually in late April and May. Bison live about 20 years in captivity and 15 years in the wild.
Relationship With Humans
In their heyday, bison were the superstores of the prairie. Plains Indians ate the meat. They used the skins for clothing, shoes, boats, bedding, blankets, tipis, and drums. They turned bison bones into knives and other tools. The stomach was used as a cooking pot. Horns were used for arrow tips, and the hooves produced glue. Bison dung was burned as fuel. Today, some bison are raised on farms and ranches as a source of low-cholesterol meat.