SANTA MONICA—Officials have announced that an endangered species of frogs were found breeding in the Santa Monica Mountains last week. Mark Twain first marketed the species in his 1865 story “The Celebrated Jumping Frog of Calaveras County.”

Zach Behrens, a representative for the National Park Service, disclosed that the California red-legged frogs were discovered on March 14 by National Park Service Rangers, who located nine egg masses while examining the mountains’ creeks. Katy Delaney, a National Park Service ecologist with the Santa Monica Mountains National Recreation Area, explained that one egg mass alone can contain 1,000 to 3,000 eggs.

These amphibians reportedly began disappearing in the 1920s and 1930s when the crayfish, whose primary food sources include eggs, fish, insects, and tadpoles, entered their environment. In the 1970s, only a single red-legged frog was found.

“I was literally crying when the stream team showed me the photos of egg masses,” said Delaney in a statement. “The years of work we’ve put in is showing amazing progress. There’s still plenty of work to be done, but this is a major moment for the project.”

A reintroduction project included a 2014 procedure in which scientists transported 350 red-legged frog eggs from the mountains to a protective pen in a stream to enable them to hatch and reproduce. They were then released.

Delaney shared last week’s findings serve as evidence that the population is managing to sustain itself without contribution from humans.

The National Park Service website lists the following information on amphibians’ endangerment:

“Unfortunately, amphibians are suffering dramatic declines due to habitat destruction and modification, over-exploitation, pollution, introduced species, climate change, increased ultraviolet-B radiation (UVB) and disease.”