The terms "threatened" and "endangered" are subjective terms used by the U.S. Fish and Wildlife Service to classify animal and plant species in danger of extinction. While threatened species are judged to be in danger of becoming extinct at some point in the near future, the term "endangered" represents a more urgent priority: endangered species require immediate action and the full protection of the Federal Endangered Species Act in order to keep them from becoming extinct.
As of 2011, no endangered animals reside in Yellowstone Park. Although the U.S. Fish and Wildlife Service (FWS) lists gray wolves as an endangered species, the Yellowstone population is considered experimental and not included in this classification. Gray wolves were reintroduced into Idaho, Montana and Wyoming in the 1990s, and more than 300 individuals now live in and around the park. In its other habitats, the gray wolf is still considered endangered.
Grizzly bears were among the first animals classified as threatened by the Endangered Species Preservation Act of 1966. Yellowstone officials estimate the population in 2011 to range between 280 and 610. The elusive Canada lynx was added to the threatened species list in March 2000. Although native to the park, there have been only two confirmed sightings of the Canada lynx since 1995.
President Ulysses S. Grant declared Yellowstone the world's first national park in 1872. More than 67 species of mammal live in an area larger than Delaware and Rhode Island combined, including wolves, bison, mountain lions, elk, moose and two species of bear. In addition to these tourist favorites, the park hosts 322 different species of bird, 16 varieties of fish, 6 native reptiles and 4 amphibians. The park also houses more than 1,400 types of plants.
