San Francisco Zoo Releases 62 Endangered Garter Snakes
The San Francisco Zoo and its conservation partners have released 62 young San Francisco garter snakes into the wild in San Mateo County, marking the first release from a collaborative head-starting program for the endangered species. The zoo-raised snakes were released this fall at sites that officials are keeping confidential to protect the animals.
The San Francisco Zoo’s announcement describes the release and the science behind it. An Associated Press video report carried by Yahoo also reported the release and said more than 100 additional snakes are being raised for a planned 2027 release.
How the garter snake head-start program works
Biologists collected pregnant females from a healthy population in 2025. After the snakes gave birth at the zoo, the mothers returned to the wild while staff raised the young until they were larger and better able to withstand threats such as predators and competition for food.
Before release, the young snakes underwent genetic testing. The results helped conservation teams choose destinations: about one-third went back to the area where their mothers came from, while the rest were placed among other populations where additional animals and genetic diversity were needed.
Why this release matters for the endangered species
The San Francisco garter snake is found only in San Mateo County and a small part of Santa Cruz County. Its habitat has become fragmented, and the zoo lists threats including drought, disease, invasive species, vehicle strikes and illegal collection. The exact release sites have not been made public because of risks that include poaching and disease exposure.
The release is a milestone, not a recovery finish line. The zoo says federal delisting would require at least 10 viable, self-sustaining breeding populations, each with 200 or more snakes. The first head-started cohort is intended to strengthen existing populations while research and habitat work continue.
Sources: San Francisco Zoo & Gardens; Associated Press video report via Yahoo.
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