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American Bison Adaptations

American bison are most commonly referred to as bison or buffalo. Bison are grazing animals and eat mostly grasses and sedge. Bison live in the plains of the United States, primarily in nature preserves and national park areas as well as on private ranches, where they are raised for meat. The greatest public population of bison in the United States is in Yellowstone National Park. Here bison can be seen year-round in the Hayden and Lamar valleys. In the 1800s American settlers hunting for sport and meat killed an estimated 50 million bison. Private ranching and national park efforts have succeeded in reviving the bison population and there are approximately 30,000 bison in the United States living in public and private herds.

Size
- Bison are quite large. Male bison weigh up to 2,000 pounds and female bison weigh up to 1,000 pounds. They are the largest land mammals found in North America. At the shoulder they stand between 5 and 6.5 feet tall. Their large size makes them less susceptible to wild predators. The only large carnivorous predators that bison face in the wild are wolves and grizzly bears. While it is possible for wolves and grizzly bears to kill bison, due to their size these predators prefer to attack younger or sickly bison.
Speed
- Bison are very large but they are also quite fast and nimble for their size. Bison are able to reach speeds more than 30 miles per hour. Bison also have the ability to rapidly pivot. This quick turning motion and their speed are a primary benefit to bison if they are attacked by predators such as grizzly bears or wolves. The predators find it difficult, and sometimes impossible, to aim for the hindquarters of a pivoting bison.
Coat
- Bison have very thick, shaggy outer coats and under-coat. They also have have thick skin. Their coat and skin keeps them well insulated in winter so they can withstand snow drifts and storms. When snow falls on bison, it does not melt due to their natural insulation. In the summer bison molt, or shed, their thicker fur. They can be seen rolling in patches of dirt to aid in molting. Rolling also helps the bison remove biting flies and insects.
Hump
- Bison have a large hump on their back above their shoulder blades. Bison humps are different than humps found on mammals such as camels. In camels, the humps are comprised of fat. The bison's hump is made up of muscle which is needed to support the head. The muscles are also supported by vertebrae. These strong muscles are used by the bison in the winter months when they swing their heads to move snow aside to make it easier to graze and travel.

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