Scientific Classification
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Artiodactyla
FAMILY: Bovidae
GENUS: Bison
SPECIES: B. bison
Plains Bison and Wood Bison
The bison in North America are divided into two subspecies: plains bison and wood bison. Plains bison are usually smaller in size and have a rounded hump, while wood bison are larger and have a taller, square hump.
These large mammals are actually the largest land animal in North America! The largest males can grow almost 7 feet tall at the shoulder and weight over 2,000 pounds! Like most ungulates, female bison are smaller than the males, but not significantly.
A bison’s coat varies by season. In the summer, they have a lighter-weight, light-brown color. In winter, they develop a shaggy, long, dark-brown pelt to keep them warm in the harsh winters.
Huge populations of bison used to roam North America; historians have calculated past herds to have as many as 30-million members! Today, bison numbers are much smaller. Still found sparsely throughout North America, the two largest populations are found in Yellowstone National Park and Wood Buffalo National Park.
Bison prefer open or semi-open habitats such as grasslands, prairies, plains, scrublands, and more. Even though they are not known as high-altitude animals, they can be found at elevations above 8,000 feet in Yellowstone and above 10,000 in the Henry Mountains!
Like most large ungulates, bison graze on grass and sedges. Since they do not have any front top teeth, bison chew by pressing their bottom teeth against the fleshy pad at the roof of the mouth. Bison have no shortage of food in the winter since they simply shovel snow out of the way with their strong, woolly snouts to get to the grass.
Male bison live in bachelor herds, while females live in herds composed of other females and their offspring. The two herds usually only mix during mating season. Dominant males get to breed first for about 2-3 weeks while non-dominant ones breed with whatever females are left after.
Once pregnant, the female bison carries the developing calf for a little over 9 months, and goes to a secluded place to give birth. Once born, within an hour or less, the calf can run and walk with the herd. They are a reddish-brown color when born and range from 30-60 pounds at birth. She will nurse them for 8-9 months.
Bison helped their prairie habitats thrive in numerous ways. For example, their dung fertilized soil. And they would create wide depressions in the ground so the herd could take dust baths. These depressions would eventually fill with water to support thirsty animals and even frogs and salamanders!
