The American bison is a North American species of bison that once roamed the grasslands of North America in massive herds. It became nearly extinct through a combination of commercial hunting and slaughter in the 19th century and the introduction of bovine diseases from domestic cattle, and has made a recent resurgence largely restricted to a few national parks and reserves. Bison are herbivorous, grazing on the grasses and sedges of the North American prairies. They reach a height of 8.2 feet, weigh 700 to 2200 pounds, and live 12 to 20 years in the wild.