Researchers from the San Diego Zoo Global Wildlife Conservancy let 65 mountain yellow-legged frogs head off into the wild on their own on June 10.

The frogs are part of a critically endangered species and were bred at the zoo’s Institute for Conservation Research. This is the first time this species has been reintroduced into the wild.

“Right away, they were exhibiting natural behaviors,” said research coordinator Frank Santana. “I think they’re well-positioned to survive. They have these natural instincts to avoid predators.”

Some of the frogs are carrying tiny backpacks that can help the scientists pinpoint their location, allowing them to determine how they’re doing.

Watch more Vetstreet animal videos.