Western Terrestrial Garter Snake (Thamnophis elegans)

Western Terrestrial Garter Snake (Thamnophis elegans)



General Distribution
This often-abundant garter snake is found in the Coast Ranges from the Oregon border south to southern Santa Barbara Co., throughout northern California including the northern Sacramento Valley, and the Sierra Nevada south to southern Tulare Co. Also found in the San Bernardino Mts. of southern California. Associated with permanent or semi-permanent bodies of water in a variety of habitats. Elevation sea level to 3660 m (12,000 ft).
Habitat Requirements
Prefers holes, especially small mammal burrows, crevices, and surface objects. Often basks in the open near cover. In cold areas garter snakes often spend the period of winter inactivity aggregated, sometimes with other species, in fissures, in rocky accumulations, in mammal burrows, or other suitable hibernacula. In milder areas mammal burrows and surface objects such as flat rocks and rotting logs serve as winter refuges.
Reproduction
Courtship occurs in spring soon after emergence. Seven to 30 young are born in July and August.
Daily/Seasonal Activity
An active diurnal snake. During the warm days of summer most activity occurs during morning and late afternoon. During cooler weather of spring and fall and at higher elevations snakes restrict their activity to the warm afternoons. On warm days during winter, garter snakes have been observed to emerge and bask in the sun at the entrances of hibernacula.
Diet and Foraging
Over much of its range this species feeds on terrestrial prey to a larger degree than the other garter snakes with which it occurs. Small mammals, birds, fishes, frogs, (especially during the metamorphic peak), salamanders, insects, crabs, marine polychaete worms, leeches, earthworms, gastropods (snails and slugs), and even regurgitated gull foods and camper refuse have been listed among the food items taken (Fitch 1941, White and Kolb 1974, Wassersug and Arnold 1976).
Territoriality/Home Range
The nature of the home range of garter snakes in California is not well known. There is likely considerable overlap in the home ranges of neighboring individuals, as snakes can be located every few meters along suitable shorelines. Not thought to be territorial. Although this species is not well studied, other garter snakes have not been observed exhibiting behaviors suggesting territoriality.
Predator-Prey Relations
Western terrestrial garter snakes are taken as prey by mammals, birds, and other snakes despite the release of a repulsive musk from the postanal glands of disturbed individuals.
Literature Cited
Aleksiuk, M. 1977. Cold-induced aggregative behavior in the red-sided garter snake (Thamnophis sirtalis parietalis). Herpetologica 33:98-101.
Fitch, H. S. 1941. The feeding habits of California garter snakes. Calif. Dept. Fish and Game 27:1-32.
Fitch, H. S. 1983. Thamnophis elegans. Cat. Am. Amphibians and Reptiles 320.
Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. 2nd ed., revised. Houghton Mifflin, Boston. 336pp.
Wassersug, R. J., and S. J. Arnold. 1976. Differential predation on tadpoles, metamophosing individuals and frogs by garter snakes (Genus Thamnophis). Herpetol. Rev. 72:101.
White, M., and J. A. Kolb. 1974. A preliminary study of Thamnophis near Sagehen Creek, California. Copeia 1974:126-136.

 
Information gathered from California DFG - California Interagency Wildlife Task Group