After the park was fenced, a horse round-up held in 1954 removed 200 branded animals. A few small bands of horses eluded capture and went unclaimed. These horses continued to live free-range in the park. For several years the National Park Service tried to remove all horses from the park. In 1970, a change of park policy recognized the horse as part of the historical setting. New policies were written and enacted to manage the horses as a historic demonstration herd. (The horses do not fall under the protection of the Wild Free-Roaming Horses and Burros Act which only applies to animals on US Forest Service and Bureau of Land Management lands.)