RANGE: Sierra Nevada Mountains of California and Nevada, from southern Plumas County to southern Tulare County

STATUS: Not listed under the Endangered Species Act; petitioned for protection by the Center for Biological Diversity in 2000

THREATS: Predation by introduced trout, pesticides, environmental changes from drought and global warming, disease, and habitat degradation due to livestock grazing

The mountain yellow-legged frog was once the most abundant amphibian in the Sierra Nevada Mountains, but today the hardy survivors of freezing Sierra winters are vulnerable to a host of modern threats, which have driven the frogs extinct in more than 93 percent of their ancient home. The main reason for the frog’s decline is the introduction of nonnative trout to high Sierra lakes by the California Department of Fish and Game — stocked fish that prey on tadpoles and young frogs. Scientists predict that the yellow-legged frog could be extinct in the Sierra within decades.

LEARN MORE ABOUT THE SIERRA NEVADA MOUNTAIN YELLOW-LEGGED FROG