<P> In 1987, the first study of mountain lion ecology was initiated in Yellowstone National Park . The research documented population dynamics of mountain lions in the northern Yellowstone ecosystem inside and outside the park boundary, determined home ranges and habitat requirements, and assessed the role of lions as a predator in the ecosystem . In recent years in other areas of the West, mountain lions have occasionally attacked humans . No documented lion / human confrontations have occurred in Yellowstone . </P> <P> The mule deer (Odocoileus hemionus) is a deer whose habitat is in the western half of North America . It gets its name from its large mule - like ears . In Yellowstone mule deer are commonly found in forests, grasslands, and shrub lands . </P> <P> The white - tailed deer (Odocoileus virginianus) occurs in aspen parklands and deciduous river bottomlands within the central and northern Great Plains, and in mixed deciduous riparian corridors, river valley bottomlands, and lower foothills of the northern Rocky Mountain regions from Wyoming to southeastern British Columbia . It is an occasional visitor to these habitats in the Yellowstone region . Both mule and white - tailed deer live an average lifespan of 10 to 15 years in the wild . </P> <P> Northern Rocky Mountain wolves, a subspecies of the gray wolf (Canis lupus), were native to Yellowstone when the park was established in 1872 . Predator control was practiced in the late 19th and early 20th centuries . Between 1914 and 1926, at least 136 wolves were killed in the park; by the 1940s, wolf packs were rarely reported . By the 1970s, scientists found no evidence of a wolf population in Yellowstone; wolves persisted in the lower 48 states only in northern Minnesota and on Isle Royale in Michigan . Canadian grey wolves were introduced into Yellowstone in 1995 . This move has returned wolves to land that was once ruled by the canine . They currently exist in several packs, the largest of which are the Slough Creek, Yellowstone Delta, and Leopold packs . The wolves had to "re-learn" an instinct that their ancestors once had: hunting bison . Being used to the elk in Canada, the wolves were dumbfounded by the large, burly bison found all over Yellowstone . However, their main prey remains elk . They have made many appearances on National Geographic Channel documentaries . Wolves in Yellowstone can live as long as 10 years in the wild, though 6 to 8 is normal . </P>

What kind of animals are at yellowstone national park