Bay Area Public Agencies and Private Organizations Team Up to Save One of the Rarest Snakes in the U.S.
First Ever Head-start Project for the Endangered San Francisco Garter Snake Aimed at Boosting Populations in San Mateo County
SAN FRANCISCO – San Francisco Bay Area’s own native snake – the San Francisco garter snake (Thamnophis sirtalis tetrataenia) – is the focus of a first-ever program to head-start what is considered one of the most beautiful snakes in the world, but also one of the most critically endangered.
The San Francisco garter snake lives only on the San Francisco Peninsula and nowhere else in the world, and has been listed as endangered in California since 1971 and federally listed as endangered since 1967. This effort focuses on repopulating areas in San Mateo County, including a location in the Golden Gate National Recreation Area (GGNRA), where only a handful of snakes remain.
Project partners include the Midpeninsula Regional Open Space District (Midpen), San Francisco Zoo, United States Geological Survey (USGS), National Park Service (NPS), Golden Gate National Parks Conservancy, and San Francisco Recreation and Parks Department, along with other state and local agencies.
For the head-start program, USGS biologists collected pregnant females from a healthy population and transferred them to the Zoo. The snakes have been housed at the Zoo, where its Conservation Team reared an estimated 120 neonate snakes this year for release in 2026 when they reach a large enough size to evade predators. The mothers were recently returned home.
Darren Fong, an aquatic ecologist for the National Park Service, has overseen habitat improvements that add new frog habitats. “With enhancements and restoration, we have created new areas to better support our population of the San Francisco garter snake. The head-start program is another important milestone in that effort,” Fong said.
“Often conservation starts at the local level—in our own backyards—and the story of the snake’s decline due to urbanization, pollution, loss of prey and habitat loss, should resonate with all of us,” said Dr. Rochelle Stiles, SF Zoo Director of Field Conservation. “This is the first time the SF Zoo is rearing this species for release to help bolster the snakes in key habitats.”
Since 2004, the Parks Conservancy and NPS restored and enhanced 33 acres of wetland, grassland and coastal scrub habitat in San Mateo County specifically for garter snakes, adding new ponds to provide breeding habitat and building elevated trails and decks to protect wildlife and allow for wildlife watching.
“Our National Park lands in the Bay Area are shining examples of how people and nature can thrive together,” said Christine Lehnertz, President & CEO of the Golden Gate National Parks Conservancy. “With the help of our staff, volunteers, and partners, we’re creating a place where endangered wildlife like the San Francisco garter snake can flourish and visitors can connect with incredible landscapes.”
The partners are grateful to the California Department of Fish and Wildlife and the U.S. Fish and Wildlife Service (USFWS) for their contributions to this vital project.
“The San Francisco garter snake is truly on the brink of extinction, and was recognized before the Endangered Species Act even existed. Fortunately, it’s not too late for them. Together, we are acting as their life support,” said Midpen biologist Ariel Starr.
SF Zoo’s previous work included successfully breeding snakes in order to develop captive husbandry techniques starting in the 1990s. The Zoo also collaborated with San Diego Zoo starting in 2005 to further develop husbandry protocols for this and other garter snakes. These husbandry protocols include specific housing techniques, nutritional guidelines, growth and maturity tracking, and regular monitoring for parasites or other anomalies, which will contribute greatly to positive outcomes.
The San Francisco garter snake is a subspecies of the common garter snake and was endemic historically throughout the San Francisco peninsula, from San Francisco to Santa Cruz. The wild population today is limited to pockets in San Mateo County. Until recently, SF Zoo was the only zoo in the country to house this subspecies.
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About the Golden Gate National Parks Conservancy
The Golden Gate National Parks Conservancy is the nonprofit partner of the National Park Service, supporting the Golden Gate National Recreation Area. Spanning 82,000 acres, including Muir Woods, Ocean Beach, and Alcatraz Island, the Parks Conservancy works to preserve these parks, enhance visitor experiences, and foster a community dedicated to conservation. Learn more at www.parksconservancy.org.
About San Francisco Zoo & Gardens
Established in 1929, San Francisco Zoo & Gardens connects people to wildlife, inspires caring for nature and advances conservation action. An urban oasis, the Zoo & Gardens is home to nearly 1,500 exotic, endangered and rescued animals representing up to 200 species as well as seven distinct gardens full of native and unusual plants. Located at the edge of the Pacific Ocean where the Great Highway meets Sloat Boulevard. Visit www.sfzoo.org for more information.
About the Midpeninsula Regional Open Space District (Midpen)
The Midpeninsula Regional Open Space District is a public agency with the mission to acquire and preserve a regional greenbelt of open space land in perpetuity, protect and restore the natural environment and provide opportunities for ecologically sensitive public enjoyment and education. On the San Mateo County coast, Midpen’s mission also includes preserving rural character and agricultural land of regional significance, and encouraging viable agricultural use of land resources. Midpen has protected more than 70,000 acres of public open space land in the greater Santa Cruz Mountains region since 1972. Learn more at openspace.org.
About the California Department of Fish and Wildlife
California Department of Fish and Wildlife is a state department, under the California Natural Resources Agency, with a mission to manage California's diverse fish, wildlife, and plant resources, and the habitats upon which they depend, for their ecological values and for their use and enjoyment by the public. For more information, California Department of Fish and Wildlife Home Page.
About the Golden Gate National Recreation Area
Golden Gate National Recreation Area (GGNRA), one of the largest national parks in an urban area, preserves and enhances the natural, historic, scenic and recreational resources of the lands north and south of the Golden Gate for the education, enjoyment and inspiration of people today and in the future. It was established by Congress in 1972 as part of the Parks for the People movement. GGNRA spans three counties: Marin, San Francisco, and San Mateo. With more than 15 million annual visitors, the park is both an international destination and a local treasure for the 7 million people who call the Bay Area home. Learn more at Press Kit - Golden Gate National Recreation Area (U.S. National Park Service)
About the U.S. Geological Survey
The USGS provides science for a changing world, which reflects and responds to society’s continuously evolving needs. As the science arm of the Department of the Interior, the USGS brings an array of earth, water, biological, and mapping data and expertise to bear in support of decision-making on environmental, resource, and public safety issues.
About the US Fish and Wildlife Service
The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people.