Thamnophis marcianus marcianus - Marcy's Checkered Gartersnake

Nonvenomous

Gartersnakes have toxins in their saliva which can be deadly to their prey and their bite might produce an unpleasant reaction in humans, but they are not considered dangerous to humans.

Size

13 - 42 inches long (32 - 107 cm). Normally found from 20 - 28 inches (51 - 71 cm). Neonates from 6.5 - 9.5 inches (17 - 24 cm).

Appearance

A medium-sized snake with a head barely wider than the neck and keeled dorsal scales. Tan, brown or yellowish brown with rows of large alternating black blotches arranged in a checkered pattern on the sides, and distinct yellowish stripes on the back and lower sides. There is a dark blotch on the back of each side of the head with a light area between the dark blotch and the corner of the mouth. The underside is pale and unmarked or smudged with dark pigment.

Behavior

Can be diurnal, crepuscular, and nocturnal, especially in hot weather. A good swimmer. May dive when startled. Like most gartersnakes, when picked up, this snake will often release its cloacal contents and musk.

Diet

Eats a large variety of prey: fish, amphibians, lizards, snakes, small mammals, and invertebrates.

Reproduction

Bears live young from May to October.

Range

Found in southeast California along the Colorado river and the Imperial Valley in Imperial and Riverside counties. Elsewhere, ranges east through southern Arizona into New Mexico, Texas, Oklahoma, and Kansas, and south into Mexico.

Habitat

Found in grassland, semi-arid land, and deserts, typically near water. In California, inhabits areas near streams, rivers, irrigation ditches, and irrigated croplands, in the desert.

Taxonomic Notes

There are three subspecies of Thamnophis marcianus, two occur in Mexico and south to Costa Rica. Conservation Issues (Conservation Status) Possibly increasing their range due to irrigation in the desert. Apparently not negatively affected by introduced Bullfrogs.