Description: The giant garter snake is the largest species of garter snake, with the adult snakes ranging from 37.0–65.0 inches in length. As with many snakes, the female giant garter snakes tend to be longer and larger than the males. The snakes have keeled scales, with a yellow dorsal stripe against two additional yellow stripes on either side that run the length of its body. Although, some unstriped checkered patterns have been observed. It is venomous, but harmless to humans; it possesses a very mild neurotoxic venom that helps subdue its prey. A bite to a human will at most give a red itchy rash around the area of the bite.

Habitat: Giant garter snakes prefer to inhabit stagnant or slow-moving water bodies with emergent vegetation; they use water to thermoregulate and deep and fast-moving water bodies are too cold, while emergent vegetation protects them from predators. Despite their dependence on water, giant garter snakes spend most of their time on land during the active season and all their time in brumation on land during the winter. They spend most of their time on land underground. When not underground, they seek litter or vegetation (particularly tules) to use as cover from predators and environmental extremes, and they avoid rocky or otherwise open areas. Giant garter snakes associated with rice agriculture use rice field canals during the spring and autumn and use rice fields throughout the active season, as they provide good habitat for the snakes with plentiful food, water, and cover. Due to habitat destruction, most giant garter snakes live in rice agricultural wetlands, and thus most live on private property, which provides a barrier to their study and conservation.

Range: The giant garter snake is found in Central California. Its historic range extends through much of Central California's Sacramento and San Joaquin valleys but has been reduced to a few fragmented areas in the Sacramento Valley.

Found in these States: CA

Diet: Due to their predominately aquatic lifestyle, giant garter snakes prey upon fish, frogs, and tadpoles. Historically they would prey upon local species such as the Sierran treefrog, but in current times their diet predominately consists of introduced species, most notably the American bullfrog.

Reproduction: Starting in March to mid May, male giant garter snakes emerge from hibernation search for a female to mate with. Because giant garter snakes hibernation dens are typically more spread out compared to other garter snakes, male snakes must expend more energy to find a potential mate. There is a difference observed between male and female reproductive strategies. Males were observed to have a decreased body condition during early spring, as a result of allocating energy towards mate searching and reproductive opportunities, forgoing growth and feeding. Alternatively, females were seen to have an increase in body condition around the same time, which is thought to support embryo development. Gravid female snakes have also been observed to be basking more frequently compared to males and non-gravid females, as it is thought the warmth facilitates the growth of the embryos. Giant garter snakes are ovoviviparous, meaning they carry eggs internally but give live birth. Following the spring mating season, birthing occurs from mid July to early October with average litter size of 17 young. Larger female snakes tend to produce more offspring compared to smaller females, rather than producing fewer but larger young. The size of the young is also heavily linked to availability of resources in any given year.

Status: Listed as Vulnerable because its area of occupancy is less than 2,000 km², its distribution is severely fragmented, and there is continuing decline in its area of occupancy, the extent and quality of its habitat, the number of locations, and the number of mature individuals.

Taxonomy: