Bison (Bison bison)

When America was discovered by European explorers, over 50 million bison spread as far east as New York and as far south as Mexico. By 1900, only about 300 remained on the entire continent, most of those in Canada. The initial reduction of their numbers was a natural result of human expansion to the west. To facilitate that westward expansion into Indian territory, bison were systematically slaughtered through organized hunts to force the Native Americans who depended on them to move onto government reservations. Today, wild bison herds can be found on several national parks and refuges througout the west and thousands are > > > maintained on private ranches across North America. Bison are often called "buffalo" but are not related to either the Asian water buffalo or the African cape buffalo. The misnomer probably resulted from early the Spanish word for "wild ox."

Bison are ruminants, like domestic cattle. Both sexes have hollow, curved horns with up to a 3-foot spread. Bulls often weigh more than a ton and stand 5-6 feet tall at the shoulder. Their senses of hearing and smell are much more developed than sight. Huge, broad feet are adapted to walking in snow. Bison clear a path in deep snow using their broad heads and powerful neck muscles. To take advantage of the large amount of hair on the front of their bodies, they lower their heads and face into the wind during winter storms. In summer bison take frequent dust baths to deter insects. The remnants of these wallows, sometimes a foot deep and 15 feet across, can still be seen on parts of the prairie.

Bison usually live in close family herds of 4 to 16 individuals. Sexes are typically separate except during breeding season. Breeding occurs in summer with a single calf, or occasionally twins, born the following spring. The young are reddish and born without the adult hump. Bison are mature at 7-8 years of age and live 25-30 years. They are grazers, feeding on a wide variety of prairie grasses. Bison are good swimmers and often cross rivers when migrating. This migratory habit originally kept their grassland habitat from being destroyed through overgrazing.