The giant garter snake is endemic to California’s Central Valley and is the largest species of garter snake; some grow over five feet in length. Giant garter snakes are brown, olive, or black in color, with a yellow stripe running down their back and two lighter stripes on each side.

These highly aquatic reptiles inhabit a variety of wetlands and artificial waterways, such as marshes, ponds, small lakes, streams, canals, and rice fields. The diet of the giant garter snake historically consisted of two species: the now extinct thicktail chub (a type of fish) and the endangered California red-legged frog. Today, giant garter snakes primarily feed on a variety of non-native species of aquatic fish, frogs, and tadpoles.

Invasive plants and animals, habitat loss, drought, and the impacts of climate change have greatly contributed to the decline of giant garter snake populations in the last century. Listed as an endangered species at both state and federal levels, only 5% of the giant garter snake’s historical wetland habitat remains.

(Senate Bill 765, Chapter 482, 2025)