Bison are North America's largest land animal, weighing up to two thousand pounds or one ton, with males standing six feet at the shoulder. They eat vegetation and must consume at least fifteen pounds daily. Once widespread from Alaska to northern Mexico, they are now found on private and protected land in the western U.S. and Canada. Their hump is a set of powerful muscles that supports and controls the movement of the seventy-five pound head, which they use like a plow to clear snow from grass. In Yellowstone National Park, five times as many people are injured by bison as by bears. Before European settlement there were fifty to sixty million bison in North America, but after eighteen ninety that number was reduced to one thousand; with restricted hunting, close to fifty thousand bison survive today.