San Francisco Garter Snake

North America


Thamnophis sirtalis tetrataenia


  • Habitat loss
  • Mortality through predation
  • Competition over food resource

The San Francisco Garter Snake is an endemic Californian snake species that is considered as the most beautiful serpent in North America. Its slender multi-coloured body can grow up to 3 feet in length. This endangered common garter snake is not dangerous to humans and feeds mainly on California red-legged frogs. Its elusive nature makes it difficult to fully document its habitat range but it prefers to stay in wet and marshy areas of the San Mateo County and Santa Cruz County.

Man-made settlements, road construction, and other modern developments within the surrounding habitat of the San Francisco Garter Snake had reduced the areas where it can live peacefully. And the significant loss of habitat also means being in constant competition over food resources with other garter snake species. The introduction of predatory animals in its native habitat such as bullfrogs leads to continued decline in population. And because snakes, in general, are considered as a threat, they are wilfully killed on sight by humans. Those that remain in the area are vulnerable to being eaten by birds of prey or caught by breeders for illegal pet trade.