Ground Snake, Sonora semiannulata
Ground Snake, Sonora semiannulata. Snake found as road kill in the greater Ivins area, June 2026. Length: 62 cm (2 feet 0 inches). Collection, photographs and identification courtesy of Bob Hills, Ivins, Utah.
The Ground Snake, Sonora semiannulata, is a member of the Colubridae Family of North American Racers, Coachwhips, and Whipsnakes. The Colubridae family comprises two-thirds of the world’s snake population with one thousand seven hundred sixty species placed in two hundred forty-nine genera. Many Colubrids are classified as venomous but very few are considered to be dangerous to humans. There are fifteen species in the Sonora Genus. The Ground Snake is also known as the Western Ground Snake and the Variable Ground Snake. In Mexico they are known as Culebrilla de Tierra Variable and Culebrilla Sonorense. Because Ground Snakes are so variable in appearance, there are multiple synonyms for this species. At least five different subspecies are no longer valid. Some sources still recognize subspecies based of geographic range.
Ground Snakes are highly variable in appearance. They are commonly seen with dark cross bands. These cross bands may encircle the body, form saddles, or be reduced to a single band at the neck. They may lack cross bands and have a middorsal stripe or lack markings entirely. The dorsal surface may be red, orange, brown or gray. This color may continue to the sides, or the sides might be lighter colors including greenish-gray and bluish-gray. The ventral surface is usually unmarked whitish or yellowish. Some specimens have dark bands on the ventral surface. The scales are smooth and shiny. Their pupils are round. The head is just slightly wider than the neck. These snakes are slender and cylindrical in form. Adult Ground Snakes are typically 20 cm (7.9 inches) to 46 cm (18 inches) in length.
Ground Snakes may be found in rocky, gravelly, or sandy soils, ideally with some subsurface moisture. They are often found in river bottoms, sandy hummocks, plains, and rocky hillsides that have patches of soft soil. The live in areas of thick and sparse vegetation, including thornscrub, juniper-pinon, and oak-pine habitats. They range from low elevations to 1,800 m (6,000 feet).
round Snakes consume a variety of invertebrates, including spiders, scorpions, centipedes, crickets, grasshoppers, and insect larvae. They are ambush predators that search for prey under rocks, in crevasses, and under surface cover. They swallow their prey whole, limiting the size of their prey. Their saliva is mildly toxic to help subdue prey. They are prey for a variety of birds, mammals, and other snakes. They primarily rely on hiding or burrowing to escape predators. Ground Snakes are oviparous and mating usually takes place during spring, from May to early June. Males engage in combat during the breeding season when they are competing for access to females. The females lay from 1-6 eggs between late May and August. The eggs incubate underground for about 60 days. The eggs are thin-shelled and elongate. The female provides no care for the eggs or the hatchlings. The eggs hatch in late August or September. The hatchlings average 7.0 cm (2.75 inches) to 10 cm (3.9 inches) in length. Ground Snakes are generally nocturnal, especially in warm desert climates, but may be crepuscular or diurnal when conditions allow. They spend the majority of their life underground. They move very efficiently through loose sandy soils, but are sluggish on the ground’s surface. They usually only emerge from the soil at night or during heavy rains. They are most active from spring through fall. They retreat underground for brumination during the cooler months of late November through February.
Ground Snakes are found through much of the western and southwestern United States, including Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Texas, and Utah. In Mexico, they are found primarily in the northern arid zones, including Baja California, Chihuahua, Coahuila, Durango, Nuevo León, Sonora, and Tamaulipas.
Ground Snakes may be confused with several other red and black banded snakes, including Coral Snakes, Long-Nosed Snakes, Milk Snakes and Mountain Kingsnakes.
From a conservation perspective, Ground Snakes are considered to be vulnerable in localized population and have legal protection in some areas. Overall, they are currently considered to be of Least Concern, due to their wide distribution. Major threats include road mortality and loss of habitat due to intense urbanization and agricultural development. Ground Snakes are non-venemous and are considered harmless to humans.