Bison in the United States were hunted almost to extinction. After tribes acquired horses in the 1600s, they could travel farther to find bison and hunt the animals more easily. However, they generally did not hunt to excess. The U.S. Army held a campaign in the late 1800s to eliminate bison as a way to control tribes that depended on bison. Yellowstone was the only place in the contiguous 48 states where wild, free-ranging bison persisted into the 20th century. Ironically, the U.S. Army, which administered Yellowstone at that time, protected these few dozen bison from poaching as best they could. The Lacey Act was passed in 1894 to allow stronger punishment for poachers. Even so, Yellowstone’s bison were reduced by poaching from as many as one thousand in 1872, to approximately two dozen animals in 1902. From that small herd has grown the two large herds now occupying Yellowstone National Park. Many people consider the protection and recovery of bison in Yellowstone to be one of the great triumphs of American conservation.