In summer the buffalo finds an abundance of food by cropping the sweet grass which springs up after the fires so frequent in one part or other of the prairies.  In winter, in the northern regions, it would starve, were it not possessed of a blunt nose, covered by tough skin, with which it manages to dig into the snow and shovel it away, so as to get at the herbage below.  In winter, too, the hair grows to a much greater length than in summer, when the hinder part is covered only by a very short fine hair, smooth as velvet.  Many thousands of these magnificent animals congregate in herds, which roam from north to south over the western prairies.  At a certain time of the year the bulls fight desperately with each other, on which occasions their roaring is truly terrific.