An estimated 50 million wild bison roamed the plains of North America prior to the arrival of European settlers. By 1884, only 325 survived. They were hunted to near extinction for their hides, as prizes, and to clear railroad tracks. Sometimes they were killed for sport and the entire carcass was left to rot in the sun. The photo below is of approximately 180,000 buffalo skulls. It was taken in 1892 in Rougeville, Michigan. At that time buffalo bones were used in refining sugar, making fertilizer, and in fine bone china.