Along with cougars, timber wolves are the largest top predators that live in the forest and have no predators of their own except humans. Most of the area's native mammal species are present in the forest, with the exception of grizzly bears, which have become locally extinct. Plans for their reintroduction to central Idaho have been proposed since the 1990s, but have not progressed because of concerns similar to those with the wolf reintroduction as well as fears for human safety. The northern and high elevation areas of the forest contain habitat for wolverines and the endangered Canadian lynx, but no recent sightings of these species have been reported.