The American bison, also commonly known as the American buffalo or simply buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds. On May 9th, 2016, President Obama officially named the American bison the national mammal by signing the National Bison Legacy Act. (The bald eagle will keep its status as a national symbol.)
The term buffalo is sometimes considered to be a misnomer for this animal, and could be confused with "true" buffaloes, the Asian water buffalo and the African buffalo. Bison is a Greek word meaning ox-like animal, while the name "buffalo" originated with the French fur trappers who called these massive beasts bœufs, meaning ox or bullock in French. The name buffalo is listed in many dictionaries as an acceptable name for American buffalo or bison. The term buffalo dates to 1625 in North American usage when the term was first recorded for the American mammal. It has a much longer history than the term bison, which was first recorded in 1774.
There are roughly 30,000 individual wild Buffalo or Bison in North America at this time: Six wild (free-ranging, not confined primarily by fencing or for commercial use) herds of plains bison occur in the natural range of this subspecies: two in Canada, three in the United States (Arizona, Utah, and Alaska) and one in Mexico. There are ten wild populations of wood bison within the natural range of the sub-species; all are in Canada. Wood bison no longer live in the wild in Alaska, once a part of their previous natural range.
There are two closely related subspecies of bison: the wood bison and plains bison. Physical and genetic differences distinguish the two subspecies. The wood bison is the largest living, native terrestrial mammal in North America. It is generally larger than the Plains Bison the average weight of mature males being roughly 2,000 pounds. The hump is much sharper with highest point of the hump being forward of front legs. The Plains Bison is somewhat smaller with a bull weighing in the neighborhood of 1500 pounds. The hump is more rounded with the highest point occurring more over the front legs. Please see the pictures.