Yosemite National Park is restoring the federally endangered Sierra Nevada yellow-legged frog to alpine lakes within the park.
The species was once the most common frog in mountain lakes throughout the Sierra Nevada.
Predators and diseases caused their population to decline by more than 95%.
Adult frogs are being collected from well-established populations within the park.
They will be reintroduced in seven lakes within the park, with the frogs already in two lakes.
Park experts hope the yellow-legged frog will again become self-sustaining within the next decade.
Park biologist Rob Grasso says that like the better-known California red-legged frog, made famous by Mark Twain in his story the “Celebrated Jumping Frog of Calavaras County,” the Sierra Nevada yellow-legged frog was once so numerous it was difficult to walk around a lake without stepping on them.