Even bison droppings served as a source of fuel. The Native Americans adapted their way of life to follow the bison herd as it randomly moved across its large home range. Less than 200 years ago, over 60 million bison roamed the western grasslands. Settlers described herds so dense and covering such a large area that the ground shook and the prairie appeared to move as they ranged the grasslands. By the late 1800s, however, less than 1,000 bison survived.
Experts link the decline directly to the movement of cattle onto the plains.
Cattlemen recognized the uniqueness of the plains country. Unlike eastern grasses, wild western grasses of the plains resisted drought and dried out on the open ground, providing nourishment for cattle even during winter. The cattlemen felt they faced one problem, however. Buffalo and Native Americans already occupied the grasslands. As long as they remained, the land couldn't be converted to pasture for cattle.