Bison (Bison bison)
The American Bison became the first national mammal of the United States when President Barack Obama signed the National Bison Legacy Act into law on May 9, 2016.
Since the late 19th century, the Department of the Interior has been the primary national conservation steward of the Bison. Public lands managed by them support 17 Bison herds—or approximately 10,000 Bison — in 12 states, including Alaska. Yellowstone National Park is the only place in the U.S. where Bison have continuously lived since prehistoric times. What makes Yellowstone's Bison so special is that they're the pure descendants (free of cattle genes) of early Bison that roamed the land.
Although the terms are often used interchangeably, buffalo and Bison are distinct animals. Old World “true” buffalo (Cape buffalo and water buffalo) are native to Africa and Asia. Bison are found in North America and Europe. Bison have large humps at their shoulders and bigger heads than buffalo.
DESCRIPTION: American Bison are covered in dark brown dense fur, which they shed in spring and early summer. In the winter their thick coats can be such a good insulator that snow will not melt on their backs. Their coats' thickness insulates them from harsh winter weather with two layers of hair and a thick hide. The coarse outer layer serves as protection from cold and moisture. The inner layer consists of fine fibers, creating an insulation that traps air and warmth. Bison have 10 times more hair per square inch than domestic cattle. They also appear to have beards, as their hair grows very long around the head and neck.
Adult Bison are between 7 to 11.5 feet long from head to rump with their tail adding an extra 20 to 24 inches. Male Bison are called bulls and can weigh up to 2,000 pounds and stand 6 feet tall. Females, called cows, weigh up to 1,000 pounds and stand between 4 and 5 feet tall.
Both male and female Bison have horns. A group of Bison is called a herd. While Bison have poor eyesight, they have excellent senses of smell and hearing. They do not moo but they do grunt, growl and snort. During mating season, bulls can be heard bellowing across long distances.
At birth a calf usually weighs between 30 and 70 pounds. Bison calves are orange-red in color, earning them the nickname "red dogs." After a few months, their hair starts to change to dark brown and their characteristic shoulder hump and horns begin to grow.
Bison can run up to 40 mph and jump vertically as high as six feet. They are quite agile and can spin quickly. They are strong swimmers too. As grazers, Bison use their huge heads as snow plows in winter to uncover vegetation to eat.
Its tail usually indicates a Bison’s mood. When it hangs down and switches naturally, the Bison is usually calm. If the tail is standing straight up it may be upset and ready to charge.
RANGE: North America – Mid and Western United States up through Canada and Alaska
HABITAT: Open plains and grasslands
DIET: Herbivore – They eat grasses, herbs, shrubs, and twigs
FAMILY LIFE: American Bison like to live and travel in groups. For most of the year herds are divided by gender, with females and calves in one herd and males in another herd. When the breeding season begins in the summer, many males temporarily join the female herd and begin looking for a mate.
Female Bison are pregnant for about nine months and give birth to one offspring. Within an hour after birth the calf stands and, soon after, begins to walk. The cows will care for their young for about a year, however, calves learn to be independent very quickly. By the middle of their first winter, juvenile Bison are feeding independently and have the typical brown fur of the adults.
LIFE SPAN: The life span of wild Bison is 20 years and up to 35 years in human care.