horse herds, thus having less impact on their ecosystem. At the same time, they occupied the heart of prime bison range which was also an excellent region for furs, which could be sold to French and American traders for goods such as guns. The Lakota became a highly powerful Plains tribe. Slaughter of the bison By the 19th century, the typical year of the Lakota and other northern nomads was a communal buffalo hunt as early in spring as their horses had recovered from the rigors of the winter. In June and July the scattered bands of the tribes gathered together into large encampments, which included ceremonies such as the Sun Dance. These gatherings afforded leaders to meet to make political decisions, plan movements, arbitrate disputes, and organize and launch raiding expeditions or war parties. In the fall, people would split up into smaller bands to facilitate hunting to procure meat for the long winter. Between the fall hunt and the onset of winter was a time when Lakota warriors could undertake raiding and warfare. With the coming of winter snows, the Lakota settled into winter camps, where activities of the season ceremonies and dances as well as trying to ensure adequate winter feed for their horses. On the southern plains, with their milder winters, the fall and winter was often the raiding season. Beginning in the 1830s, the Comanche and their allies often raided for horses and other goods deep into Mexico, sometimes venturing 1,000 miles (1,600 km) south from their homes near the Red River in Texas and Oklahoma. The U.S. federal government and local governments promoted bison hunting for various reasons: to allow ranchers to range their cattle without competition from other bovines and to starve and weaken the Plains Indian population to pressure them to remain on reservations. The bison herds formed the basis of the economies of the Plains tribes. Without bison, they were forced to move onto reservations or starve. Bison were slaughtered for their skins, with the rest of the animal left behind to decay on the ground. After the animals rotted, their bones were collected and shipped back east in large quantities. The railroad industry also wanted bison herds culled or eliminated. Herds of bison on tracks could damage locomotives when the trains failed to stop in time. Herds often took shelter in the artificial cuts formed by the grade of the