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American Bison - Bison bison

Life Cycle

 Phylum: Chordata
 Class: Mammalia
 Order: Artiodactyla 
 Family: Bovidae
 Genus: Bison

American Badger
ICUN Redlist - World Status: near threatened Near Threatened
    Audio Credit: National Park Service /Shan Burson
Bison grazingThe American bison is the largest land animal in North America. Males can stand six feet from hoof to shoulder and weigh between 1000-2000 pounds. Females are around five feet tall and weigh between 800-1000 pounds. The bison has long shaggy brown fur, a mane and beard under its chin and a long tail with a tuft of hair at the end. It has a big head with short black horns and a hump on its shoulders.

American BisonThe American bison once was found in most of Canada, the United States and parts of Mexico. Wild populations are now limited to national parks and refuges. Bison can be found in Yellowstone National Park in Wyoming, National Bison Range in the Flathead Valley of Montana, the Wichita Mountains National Wildlife Refuge in southwest Oklahoma, the Fort Niobrara National Wildlife Refuge in northern Nebraska, Sullys Hill National Wildlife Refuge in northwestern North Dakota, Walnut Creek National Wildlife Refuge in central Iowa and the Wood Buffalo National Park in Northwest Territory, Canada.
The American bison live on plains, prairies and river valleys.
Bison grazingThe American bison is a grazer. Its diet is made up of mostly grasses and sedges. It will occasionally eat berries and lichen. In winter, the bison uses its head and hooves to move snow off the vegetation.
Female bison are ready to mate when they are two to three years old. Males aren't ready to mate until they are about six. Mating season begins in July and can run through September. When mating season begins, male bison move into female groups and select a female. They then "tend" the female.

Bison Bull Males tend a female by staying between her and the rest of the herd. Tending can last for a few minutes or for several days. If a female isn't interested in a male, she will walk away. Males will threaten and sometimes attack other males that try to get too close to a female he is tending.
Fights between males can involve headbutting, shoving, or locking horns.

Bison calfThe female gives birth to one calf after about nine months. She will go to an isolated area to give birth. Newborn bison are reddish-brown and can stand shortly after birth. The mother and her calf will stay isolated from the herd for a couple of days. At about two months, the calf will begin to develop shoulder humps and horns. The calf is usually weaned by the time it is seven months old.


The American bison spends the warm hours of the day resting, chewing its cud or wallowing in dirt. It is most active in the early morning and late afternoon.

Bison live in a variety of groups. Females and young males may live in groups of up to 20 bison. Males also can live in groups of up to 20 males, or they can live in smaller groups or individually. Mature males and females usually live apart except during breeding season. Each bison group has a dominant male or female.


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