The Ground Snake is a small (8-18 inches long) crossbanded, striped or plain colored snake with a head that is only slightly larger than its neck.1 The top of the snake may be brown, reddish, orange or gray. The sides are lighter than the top and the bottom is whitish or yellowish. The dorsal pattern in this species varies greatly: 1) dark crossbands may encircle the body, form saddles on the top or be reduced to a single band around the neck; 2) dark crossbands may be entirely absent; 3) some populations (along the lower Colorado River) have broad beige, red or orange stripes and gray or bluish gray sides.1
Habitat: S. semiannulata is a secretive nocturnal snake of arid and semiarid lands where the soil may be rocky, gravelly, or sandy and has some subsurface moisture.1 It will frequent river bottoms, desert flats and rock hillsides where there are pockets of loose soil. Vegetation is usually sparse, as on sagebrush plains and cresote bush desert, but along the Colorado River the snake is found among thickets of mesquite and willows.1 In Pima County, a valley form of S. semiannulata is found in desert grassland with clay loams or heavy, silty clay loams.
Range: The species occurs from the Snake River region of southwest Idaho to the tip of Baja California, and from southeastern California to east-central Texas. The species is found in elevations ranging from sea level to 6,000 feet.1
Reproduction: The Ground Snake will lay a clutch of 46 eggs in late June or July which will hatch in about two months.2
Diet: This species eats spiders, scorpions, centipedes crickets, grasshoppers and insect larvae.1
Status: Currently, there is no federal or state status identified for the Ground Snake.
Ground Snake in Pima County: The main concern in Pima County is for the valley form of Ground Snake found in the tobasa grassland of the Tohono O'Odham Nation. Small numbers of this form, which may be a subspecies, are found with more common forms of S. semiannulata. A population in Marana is unique and abundant enough to be of special interest.3
1. Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Second edition, revised. Houghton Mifflin Company, Boston.
2. New Mexico Department of Game and Fish et al. 1998. BISON-M: New Mexico Species List/Species Accounts.
3. RECON. 2001. Priority Vulnerable Species. Pima County Administration
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