Before the arrival of Europeans, more than 60 million American bison roamed the prairies and plains of North America. From the Alaskan wilderness to the rich grasslands of northern Mexico, and from the Appalachian Mountains to the Great Basin of Nevada, the annual migration of bison across the continent in massive herds not only shaped the richly diverse grasslands upon which they thrived but were also an integral part of the culture and survival of indigenous peoples of North America for hundreds of thousands of years.