The American Buffalo (Bison) never faced extinction until the American westward migration.

...Thus, according to Ward Churchill, (click here) a professor of ethnic studies at the University of Colorado, the reduction of the North American Indian population from an estimated 12 million in 1500 to barely 237,000 in 1900 represents a"vast genocide . . . , the most sustained on record." By the end of the 19th century, writes David E. Stannard, a historian at the University of Hawaii, native Americans had undergone the"worst human holocaust the world had ever witnessed, roaring across two continents non-stop for four centuries and consuming the lives of countless tens of millions of people." In the judgment of Lenore A. Stiffarm and Phil Lane, Jr.,"there can be no more monumental example of sustained genocide—certainly none involving a 'race' of people as broad and complex as this—anywhere in the annals of human history."...