Bison

"Nearly Destroyed: Once 50 million American bison, also known as American buffalo, roamed the Great Plains of North America. This symbol of the American frontier was nearly destroyed due to overhunting by the settlers of the 19th century. Conservation efforts saved the bison from the brink of extinction, but the fraction that remain are either captive or come from captive stock." http://animal.discovery.com/mammals/bison/