Scientifically, the term "buffalo" is incorrect for the North American species; its proper Latin name is Bison bison. However, common usage has made the term "buffalo" an acceptable synonym for the American bison. The American bison (Bison bison), also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds. Their range once roughly comprised a triangle between the Great Bear Lake in Canada's far northwest, south to the Mexican states of Durango and Nuevo León, and east along the western boundary of the Appalachian Mountains. In the seventeenth century, French explorers in North America referred to the new species they encountered as "les boeufs", meaning oxen or beeves. The English, arriving later, changed the pronunciation to "la buff". Early American settlers called bison “bufello” due to the similar appearance between the two animals, and the name "buffalo" remained - although incorrect - for the American variety.

Bison are North America's largest land mammal; and they are ruminant animals in the bovine family. Descendants of the European Wisent, during the Pleistocene Ice Age, the ancestors of today's bison-bison - the bison priscus - crossed from Siberia into Alaska. Bison priscus evolved into bison-latifrons and lived in North America for 300,000 years. 22,000 years ago bison-latifrons evolved into bison-antiquus. 10,000 years ago bison antiquus evolved into today's bison-bison.

40 - 60 Million heads is estimated to have lived in North America prior to 1600. As part of the U.S. government's plan to eliminate the Native Americans, bison were slaughtered in great numbers to eliminate the Native American's food source. They were also slaughtered for their hides, tongues, and their bones were used for fertilizer. Which led to their near extinction. Estimated less than 500 heads were the number of bison prior to efforts were made to preserve and restore the species. Today there are around 200,000 buffaloes in The United States. Yellowstone has the largest free roaming buffalo population in the world. The herd numbers at about 3,500-head.

The American bison once roamed the grasslands of North America in massive herds. Their range once roughly comprised a triangle between the Great Bear Lake in Canada's far northwest, south to the Mexican states of Durango and Nuevo León, and east along the western boundary of the Appalachian Mountains. Because of commercial hunting and slaughter in the 19th century, the bison nearly became extinct. Early American settlers called bison “bufello” due to the similar appearance between the two animals, and the name "buffalo" stuck for the American variety.

Differences from European Bison

Although they are superficially similar, the American and European bison exhibit a number of physical and behavioral differences. The American species has 15 ribs, while the European bison has 14. The American bison has four lumbar vertebrae, while the European has five dubious – discuss Adult American bison are not as rangy in build, and have shorter legs. American bison tend to graze more, and browse less than their European cousins, due to their necks being set differently. Compared to the nose of the American bison, that of the European species is set farther forward than the forehead when the neck is in a neutral position. The body of the American bison is hairier, though its tail has less hair than that of the European bison. The horns of the European bison point forward through the plane of its face, making it more adept at fighting through the interlocking of horns in the same manner as domestic cattle, unlike the American bison which favours charging.