The economy of the Plains Indians was dependent on the American bison,
usually called the buffalo: flesh provided food; bones were used for
tools, ornaments, and arrowheads; hooves for rattles; tendons for thread;
and the skin for clothing;.  Before the introduction of the horse, Indians
stalked the buffalo on foot, creeping up to a herd disguised in animal
skins, and stampeding them over a cliff or into a corral.  The horse made
buffalo hunting easier and more profitable, and allowed Indians from other
regions to move into the area and take up buffalo hunting as a way of
life.  The painting above shows women stretching freshly skinned buffalo
hides.