Scientists bring extinct frogs back to Southern California in big AI leap for preservation

Scientists in Southern California have successfully reintroduced native red-legged frogs to the region using artificial intelligence and cross-border collaboration with Mexico. The breakthrough came when AI analysis of pond recordings confirmed breeding calls in January, marking the first successful reproduction of the species in Southern California after nearly disappearing from 95% of their historical range.

The big picture: This conservation success represents a rare example of effective wildlife restoration across international borders, combining cutting-edge AI technology with traditional field biology to bring back a species that had virtually vanished from Southern California.

Key details: The red-legged frog, believed to be the star of Mark Twain’s “The Celebrated Jumping Frog of Calaveras County,” was decimated by invasive bullfrogs, habitat loss, and disease over the past century.

• Scientists found that Southern California’s extinct population was genetically closer to Mexican frogs than to any remaining California populations.
• In 2006, researchers discovered about 20 red-legged frogs in Baja California, Mexico, which became the source for the reintroduction effort.
• The Mexican population has since grown from 20 to as many as 400 adult frogs.

How AI changed everything: Artificial intelligence transformed the painstaking process of monitoring frog populations by automatically analyzing hours of audio recordings.

• Previously, scientists had to manually listen to countless hours of audio files to detect the red-legged frog’s distinctive call, which “resembles the sound of a thumb being rubbed on a balloon.”
• AI can now process 18 hours of pond recordings in just three minutes, identifying various species while filtering out background noise from “tree frogs calling, there’s cows mooing, a road nearby with a motorcycle zooming back and forth.”
• The technology is being expanded to potentially provide real-time satellite audio feeds to scientists’ phones.

Cross-border cooperation: The project required unprecedented international coordination, especially during the COVID-19 pandemic.

• Anny Peralta, a former student at San Diego State University, and her husband established the nonprofit Fauna del Noroeste in Ensenada, Mexico to breed frogs specifically for cross-border relocation.
• During the pandemic, teams had to secure special permits and arrange flights to transport coolers of frog eggs across the U.S.-Mexico border.
• The eggs had to pass U.S. border guard inspection before continuing their journey north.

Why this matters: The success demonstrates how AI can accelerate conservation efforts for endangered species while proving that wildlife restoration can transcend political boundaries.

• More than 100 adult red-legged frogs now inhabit Southern California ponds, with tadpoles spotted at new sites.
• The restored ecosystem is already showing benefits, including fewer disease-carrying mosquitoes.
• Scientists plan to continue transporting egg masses from Baja to build thriving populations on both sides of the border.

What they’re saying: The breakthrough moment came with clear audio evidence of success.

• “It felt like a big burden off my shoulder because we were thinking the project might be failing,” said Brad Hollingsworth of the San Diego Natural History Museum. “And then the next couple nights we started hearing more and more and more, and more, and more.”
• “They don’t know about borders or visas or passports,” Peralta said of the frogs. “This is just their habitat and these populations need to reconnect. I think this shows that we can restore this ecosystem.”