San Francisco Garter Snake

Thamnophis sirtalis tetrataenia (Herps (reptiles and amphibians))

Species Description

The San Francisco Garter Snake has been called North America’s most beautiful serpent. A fantastically colored species that does justice to its moniker, it is identified by its reddish-orange head with red, black, and blue racing stripes on its sides and back.

Keep in mind that the more-common Coast Gartersnake (Thamnophis elegans terrestris) can sometimes look similar to the San Francisco Gartersnake. The Coast Gartersnake has a brown head, whereas the San Francisco Garter Snake has an orange or red head, and will not have any spotting on its blue/green belly.

A Snake on the Brink

Unfortunately this harmless and gorgeous critter isn’t easily seen, in part because it is on the brink of extinction. Restricted primarily to San Mateo County, the species’ preferred habitats—wet and marshy land with access to upland areas—have been hit hard by agricultural, residential, commercial, and even recreational development. There may be only one to two thousand individuals remaining in the wild today.

The San Francisco Garter Snake was protected by federal law as early as 1967, and was listed an endangered species under the Federal Endangered Species Act when the Act was passed in 1973. Since that time great effort has gone into conserving the species, including the creation of a recovery plan and controlling developments to ensure that the species’ habitats aren’t adversely modified. It was too late, however, to stop development at Sharp Park Golf Course.

The San Francisco Garter Snake and Sharp Park Golf Course

Historically Sharp Park in Pacifica, California provided excellent habitat for the San Francisco Garter Snake. It contained a vibrant feeding lagoon, now called Laguna Salada, and upland refuge areas and basking habitats where the snake could rest and warm itself in the sun.

In the 1940s, Dr. Wade Fox surveyed Sharp Park for the first time, and found the species to be abundant and of remarkable purity. It thrived there long-before San Francisco began developing the area.

Unsurprisingly, Dr. Fox also discovered that the recently built Sharp Park Golf Course was having detrimental impacts on this beautiful serpent. In 1946, he found a snake killed by golfers, and noted that the species was probably frequently killed in this manner.

Over the next few decades the snake’s population crashed. In 2006 the U.S. Fish and Wildlife Service concluded a dead snake found on the property was killed by the course’s lawn mowers.

The population crash and on-going take of the Garter Snake is particularly worrisome because the survival of the Sharp Park population is key to the success of the species’ overall recovery plan. Unfortunately, the population at Sharp Park Golf Course has crashed since that time: there may be fewer than 10-20 individuals left on the property.

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Conservation Action Item

There is no currently active Big Year.

No action has been set for this species!


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