BISON, a form of wild cattle regarded by some naturalists as constituting a genus Bison, separated from the larger group Bos, which is represented by the American ebuffalo,a the European aurochs, and some extinct species. Bison differ from other cattle, in external appearance, mainly by their massive and shaggy forms. Their heads are exceedingly broad, and the horns curve outwardly from each side of the forehead, and are short, round and thick. A mop of long and shaggy hair covers the fore head, nearly hiding the little eyes, and forms a great beard upon the throat and chin, espe cially of the bulls. In order to support this massive head, which is usually carried low, great spines rise from the vertebra of the back over the shoulders, giving attachment to the huge muscles necessary to support the skull. This makes the neck very thick, and the fore-quarters much higher than the haunches, which droop away from the arched contour of the back, over the withers. The massive ap pearance of the fore-quarters is increased by the long growth of hair on the neck, shoulders and fore-legs, which is especially coarse and shaggy in bulls, and is of protection to them in their .furious assaults upon one another in the rutting season. This hair consists mainly of a short, crisp, wool-like growth, different from that of other cattle, and capable of being woven. Internally, the bison are peculiar in having 14 ribs instead of 13; in the breadth and convex ity of the frontal bones of the skull, in having six instead of four nasal bones; and in the com parative slenderness of the bones of the limbs. The bison are inhabitants of the northern hemisphere, and, in the era preceding the pres ent, were represented by two or three species of probably circum-polar range. The race is rep resented in the Old World by the aurochs, now preserved only in small, protected herds in Russia (see AtiRocits) ; and in America, by the buffalo (Bison americanus), now nearly extinct.
The American bison or buffalo is somewhat smaller than the aurochs, and has shorter and thicker horns, and a shorter tail, but its hump and fore-quarters are higher, and more shaggy. The females are much inferior to the males in bulk, weighing only about 1,200 pounds, whereas an old bull in good condition will weigh 2,000 pounds. The American animal differs in one very important respect from the European spe cies, due to the difference in their habitats.
The auroch was a native of a region covered with forests, where large herds could not find open pasturage of any considerable extent, and consequently moved about only in small bands, whereas the American animal had open to it the immense, this prairies and plains of the interior of this continent, and was able, and in effect, forced to join into vast herds, so that it acquired gregarious habits. When North America was explored by white men, the bison was first encountered in the valleys of the Alle ghanies, and scattered throughout the prairies of the Mississippi Valley, north of the Tennes see River. Its principal home, however, was upon the grassy plains, between the Missouri River and the Rocky Mountains, where the herds sometimes contained hundreds of thousands of individuals, and grazed all the way from south ern Texas to the shores of Great Slave Lake. They wandered through the valleys of the Rocky Mountains, to the plains of New Mexico, Utah and Idaho, but seemed never to have crossed the Sierra Nevada. Those east of the Missis sippi River were probably killed off before the beginning of the 19th century, and by 1850 none remained east of the dry plains. The building of the Union Pacific and Kansas Pacific rail roads, where the early trains were sometimes stopped by herds crossing the tracks, soon led to the disappearance of the animals from the central plains; and by 1875 they were divided into two distinct groups, a northern and a southern. These were rapidly slaughtered by parties of men who followed the animals at all seasons, and killed them for their hides, which, as °buffalo robes° became more and more valu able, until by 1890 the Texan herd had been utterly exterminated, and of the northern herd none remained except such as had been gathered by the government for preservation in Yellow stone Park, and a few hundred that still sur vive in the remote forests beyond the North Saskatchewan. The herd in Yellowstone Park will probably be maintained under the protec tion of law. Small bands are living in private parks and zoological gardens in various parts of the world. In 1913 there were 3,453 living bison, the sole relic of the millions of these valuable animals, which half ,a century ago ranged our western plains, and which were reck lessly destroyed.