Members of the genus Bison are large, even-toed ungulates within the subfamily Bovinae. Two extant and four extinct species are recognized. The surviving species are the American bison, also known as the American buffalo [although it is only distantly related to the true buffalo], Bison bison, found in North America, and the European bison, or wisent [Bison bonasus], found in Europe and the Caucasus.
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, became nearly extinct by a combination of commercial hunting and slaughter in the 19th century and introduction of bovine diseases from domestic cattle, and has made a recent resurgence largely restricted to a few national parks and reserves. Their historical range 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.