so-called 'Hostiles', unless they were immobilized in their winter camps, could, however, strike at a more accessible target, namely, the buffalo. That tactic also made curious sense, for in soldiers' minds the buffalo and the Plains Indian were virtually inseparable." Native American involvement According to historian Pekka Hämäläinen, a few Native American tribes also partly contributed to the collapse of the bison in the southern Plains. By the 1830s the Comanche and their allies on the southern plains were killing about 280,000 bison a year, which was near the limit of sustainability for that region. Firearms and horses, along with a growing export market for buffalo robes and bison meat had resulted in larger and larger numbers of bison killed each year. A long and intense drought hit the southern plains in 1845, lasting into the 1860s, which caused a widespread collapse of the bison herds. In the 1860s, the rains returned and the bison herds recovered to a degree. Railroad involvement After the Pacific Railroad Act of 1862, the west experienced a large boom in colonist population—and a large decline in bison population. As railways expanded, military troops and supplies were able to be transported more efficiently to the Plains region. Some railroads even hired commercial hunters to feed their laborers. William Frederick "Buffalo Bill" Cody, for example, was hired by the Kansas Pacific Railroad for this reason. Hunters began arriving in masses, and trains would often slow down on their routes to allow for raised hunting. Men would either climb aboard the roofs of trains or fire shots at herds from outside their windows. As a description of this from Harper's Weekly noted: "The train is 'slowed' to a speed about equal to that of the herd; the passengers get out fire-arms which are provided for the defense of the train against the Indians, and open from the windows and platforms of the cars a fire that resembles a brisk skirmish." 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 track winding through hills and mountains in harsh winter conditions. As a result, bison herds could delay a train for days. Commercial hunting The main reason for the bison's near-demise, much like the actual demise of the