The mountain yellow-legged frog is a complex of two species (Rana muscosa, Rana sierrae) that has existed in the mountains of California and adjacent Nevada for millions of years, moving up and down in elevation as glaciers repeatedly advanced and retreated. Over these thousands of centuries, the mountain yellow-legged frog has developed numerous adaptations that allow it to thrive in even seemingly inhospitable alpine lakes, habitats too cold for any other amphibian. Ironically, the same adaptations that served the mountain yellow-legged frog so well for millions of years have also made it extraordinarily vulnerable to the nonnative trout that were stocked into many of these habitats during the past century.

Sierra Nevada yellow-legged frog, Rana sierrae Read on...