Threatened Mammals - Yosemite National Park (U.S. National Park Service) Yosemite National Park’s wildlife biologists monitor all the park's mammals but focus heavily on animals listed as endangered or threatened in order to ensure their long-term survival. Of Yosemite’s special status mammal species, the Sierra Nevada bighorn sheep, the California wolverine, and the Pacific fisher are listed under the U.S. Endangered Species Act, and the Sierra Nevada red fox and the California wolverine are part of the 14 mammals protected by the state of California.