Hundreds of species of mammals , birds , fish , and reptiles have been documented , including several that are either endangered or threatened . The vast forests and grasslands also include unique species of plants . Yellowstone Park is the largest and most famous megafauna location in the contiguous United States . Grizzly bears , wolves , and free-ranging herds of bison and elk live in this park . The Yellowstone Park bison herd is the oldest and largest public bison herd in the United States . Forest fires occur in the park each year ; in the large forest fires of 1988 , nearly one third of the park was burnt . Yellowstone has numerous recreational opportunities , including hiking , camping , boating , fishing and sightseeing . Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls . During the winter , visitors often access the park by way of guided tours that use either snow coaches or snowmobiles
large forest fires of 1988
Yellowstone fires of 1988
Yellowstone National Park