American bison are large herbivores that were once common on the prairies. It is estimated there were as many as 200 million of them on the prairies at one time. These grazing animals feed mostly on grass and sedges (grass-like plants). Traveling in large herds, they roamed the prairies in search of high quality forage to eat. Their movements were largely influenced by where fire occurred. Following a fire, the grass in an area would regrow and the new growth is very desirable. Bison followed the fire in what is called a fire-grazing interaction. As the bison grazed an area, other areas had a chance for the grass to grow taller providing more fuel for the next fire. Thus, the bison influenced where fire occurred.
Native Americans relied heavily on bison. They used them for food, clothing and shelter. When European settlers arrived on the prairies, they began hunting them heavily. The bison were nearly driven to extinction. Fortunately, a few survived and bison were able to be reintroduced around the country, primarily in parks and preserves. Today, bison occur on only a small portion of their original range. They have been largely replaced by cattle as the dominant large herbivore on the prairies.