There were about 6 million bisons roaming the plains of North America 400 years ago. Now, however, they are gathered mostly in zoos, parks, ranches, and wildlife preserves. You can still find a large number of bisons at the Great Plains.
Bisons are the largest mammals in North America. They can stand up to 6 - 7 feet (1.8 - 2.1m). An average bison weighs about 2000 pounds (907.2kg). Males, called bulls, are sometimes twice as big as females, the cows. They can run as fast as horses, about 35 miles per hour (56.3 km/hr). The bisons have a huge hump on their back. This hump is really a large shoulder muscle that holds up the bison's head. They have black fur on the head and brown fur on the body. There are 2 horns on their head. Sometimes the horns measure up to 3 feet (.9m) from tip to tip. The skin is very thick. It can keep the bisons warm even in very cold weather.
They are herbivores. Bisons eat grass, leaves, and twigs. They have flat teeth called molars. Since they are enormous animals, bisons need to eat several pounds of food each day. Unless they are resting, bisons travel in herds to graze on grass.
Spring is usually the time when females give birth to their young. The calves are red in color and have weak frail legs. Within months time they learn to walk and milk from their mother's teats. The horns also grow and the hump on the back starts to develop. When they are one year old, it weighs between 300 - 400 pounds (136 - 181.4kg). They leave their mothers when they are two. When they are about 8 years old, the young bisons are ready to start their own family.
When the settlers came over to the New World, thousands of bisons were killed. They destroyed and took over the habitats of the bisons. Thousands of bisons were killed for their meat and hide. By the end of the 1800s only a few hundred were left in the wild. Now, because of conservation programs there are about 50,000 bisons roaming in North America.