Southern Mountain Yellow‑Legged Frogs Leap Back into the Wild to Boost Vulnerable Populations

11 July 2025

Southern California mountain yellow-legged frog.(Jamie Pham / L.A. Zoo)

On July 10, 2025, the Los Angeles Zoo joined forces with the U.S. Geological Survey and the Aquarium of the Pacific to reintroduce 643 endangered southern mountain yellow‑legged frogs into the pristine streams of the San Gabriel Mountains. This carefully coordinated release included 450 tadpoles and 193 subadult frogs, all of which were bred and nurtured within the zoo’s specialized conservation facilities. The program, which began in 2007, has already seen more than 6,000 of these amphibians returned to their native habitat, helping to restore a species decimated by disease, habitat loss, introduced predators, and environmental stressors.

The reintroduced frogs were transported from the zoo in temperature‑regulated coolers to a secure, undisclosed release site to ensure their safety as they adjust to life in the wild. L.A. Zoo keeper Luc Myers described the experience during field work in the San Gabriels as “nothing short of amazing,” reflecting the emotional power of witnessing these fragile creatures return to the ecosystem from which they had nearly vanished.

Measuring between 1.5 and 3.25 inches and sporting distinctive brown and yellow camouflage with dark speckles, these medium‑sized frogs are well adapted to evading predators in their native streams. However, their numbers plummeted by approximately 90 percent across their southern California range by the 1970s, making conservation interventions critical.

This latest effort marks the continuation of a decades‑long strategy to combat population decline, bolstering numbers through head‑starting raising amphibians to a less vulnerable stage in captivity before reintroduction. The collaboration exemplifies a dynamic partnership model, with federal, zoo, and aquarium partners aligning resources to support a species recovery plan across multiple mountain ranges.

Public investment in habitat restoration and captive rearing programs has also intensified. The zoo recently committed additional space to extend the pre‑release care period for tadpoles, increasing their chances of survival post‑release. Long‑term monitoring of released individuals is planned to assess their adaptation to natural conditions, evaluate breeding success, and refine future release protocols.

As climate change, chytrid fungus, and invasive species continue to threaten amphibian survival, the southern mountain yellow‑legged frog remains emblematic of broader biodiversity crises affecting high‑elevation habitats. But each successful release offers tangible hope and a model for restoring other imperiled species.

This substantial release enriches our collective understanding of conservation impact and reaffirms the power of sustained ecological stewardship. As these resilient frogs begin to hop back into the streams fragile yet firm, they bring with them the promise of renewal and the urgent reminder that dedicated, science‑based action can foster recovery for species once teetering on the edge of disappearance.