Bison cow and calf
Bison cow and calf

NPS (Jack O'Brien)

(Note: Though Bighorn Canyon NRA does not have a bison herd, many visitors who drive the Ok-A-Beh Road in the North District sometimes see bison. That is because the road crosses Crow Tribal Land. The Crow Reservation contains a large herd, numbering upwards of 1,100 bison.

Bison are the largest land mammal in North America – bigger than elk, moose, and grizzly bears! The male bison is called a bull. Mature bulls weigh up to 2000 pounds and stand as high as six feet at the hump – this is bigger than some sports cars. Female bison, called cows, are smaller than males, weighing as much as 1,000 pounds and standing about five feet at the hump. Bulls and cows living in natural settings have a lifespan of 12 to 15 years, but may live twice as long. An exceptionally hardy animal may live up to 40 years.

Both cows and bulls have two black horns. The tips are sharp and grow throughout their lifetime. They never shed nor drop off like antlers. These horns are made of the same material as human fingernails but are thicker and stronger. Their thick coats act as protective blankets – the cold doesn’t get in and the buffalo’s body heat doesn’t get out.

Mating, Calving, And The Early Years
Mating season for the bison is July. During this period, buffalo become exceedingly vicious toward one another. Bison calves are born in April and May. A calf, at birth, weighs from 25 to 40 pounds. Its hair is of a yellow and reddish color until three months to a year old, when they shed this wool and take on the darker color of the adult bison. During the first two weeks of their lives, calves remain close to their mothers. Even when running, the cow and calf are seldom separated by more than ten feet from each other. Cows are very protective of their young at this age.

As calves grow older, they roam farther from the cows, perhaps up to 50 yards. However when a cow utters a series of low-pitched grunts, the calf answers immediately in a high pitched grunt and runs to join her. Just before reaching the second year, their horns emerge and begin to curve.

Other than the sounds described above, bison do make other noises, mostly of grunting, snores, and sneezing sounds. However, the most impressive vocal sound made by bison is the roaring by the bulls during the breeding season. At the peak of the rut these booming bellows rumbled across the hills or plains and can be heard for distances up to three miles in still air.

The buffalo feed about five times a day – just before dawn, mid-morning, mid-afternoon, one to two hours before sunset, and again around midnight. This feeding pattern is not as regular during the breeding season or in winter.

In the early to mid 19th century and before, predators of bison were wolves and grizzly bears. Wolves would track and kill a single bison. A grizzly, on the other hand, would attack if it discerned that a lone buffalo was injured or sickly.

Did You Know
Is there a difference in the name “bison” and “buffalo?” No. They are actually the same animal.

Buffalo were very important to sustain the physical and spiritual needs of the Crow people. They relied heavily upon the animal for their main source of food, clothing, and shelter.

Last updated: February 24, 2015

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