FRESNO (AP) — Scientists say they’re inoculating an endangered California frog to give it a fighting chance at avoiding extinction.

National Park Service biologist Danny Boiano says it’s part of an experiment to save the mountain yellow-legged frog from ravaging disease.

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The once-abundant frog lives high in California’s Sierra Nevada; disease and non-native predators nearly wiped them out.

An endangered mountain yellow-legged frog. (U.S. Geological Survey)

An endangered mountain yellow-legged frog. (U.S. Geological Survey)

Boiano’s team over three years netted nearly 400 sickly tadpoles deep in Sequoia and Kings Canyon national parks.

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Zoos in San Francisco and Oakland treated the frogs before they were returned to the wild.

Boiano says his team will next study their success, but they’ve already seen promising signs.

Jessie Bushell of the San Francisco Zoo says it may seem like a lot, but letting the frog die out isn’t an option.

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