American bison Bison bison, commonly known as buffalo in North America, grazing in meadow in Custer State Park, South Dakota. Numbering as many as sixty million before contact, they were nearly completely exterminated due to commercial hunting encouraged by the U.S. government as a way to deprive Plains Indians of their livelihood. Today bison are making a comeback and number about 350,000. Bulls can reach a height of over two meters and a weight of 1,000 kg.