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A Guide to the Amphibians
and Reptiles of California


Variable Groundsnake -
Sonora semiannulata
semiannulata

Baird and Girard, 1853
Click on a picture for a larger view



Variable Groundsnake California Range Map
Range in California: Red




observation link





Striped Phase
Variable Groundsnake
Variable Groundsnake Variable Groundsnake Variable Groundsnake
  Striped juvenile, Imperial County  
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Striped adult, Inyo County © Ryan Sikola Striped adult, Old Woman Mtns.
San Bernardino County
© 2005 Michael Rathbun.
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Adult, Inyo County © Mardee
Another groundsnake with the same coloring as this one but with bright orange saddles instead of a stripe was also found in the same area. (Shown below)
Striped adult, Old Woman Mountains, San Bernardino County
© Jeremiah Easter
  Variable Groundsnake  
  Striped juvenile, Imperial County  
     
Banded Phase
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Striped and banded adults, Inyo Couty
© Ryan Sikola
Banded adult, Inyo Couty © Ryan Sikola
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Banded adult, Inyo County Banded adult, Inyo County
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Banded adult, Lassen County
(First snake recorded from from Lassen County and Northeastern California.)
© Loren Prins
Banded adult, Inyo County
© Brad Alexander
Banded adult, Clark Mountains, San Bernardino County. © Benjamin German
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Adult male (striped) and female (banded), San Bernardino County 
© Adam G. Clause
Black and white banded adult, Riverside County © Richard Morgan II
Variable Groundsnake Variable Groundsnake Variable Groundsnake
Adult, Inyo County © Mardee
This aberrant adult missing black pigment was found near another groundsnake with more typical coloring. Another groundsnake with the same coloring as this one but with an orange stripe instead of saddles was also found in the same area. (Shown above.)
Preserved specimen (black and white banded morph) from the Bartlett Hills near the town of Joshua Tree, San Bernardino County. © Jeremiah Easter
Variable Groundsnake Variable Groundsnake Variable Groundsnake shed
Banded adult, Inyo County
© 2005 Jeremiah Easter
Adult, showing partial dark banding of the underside, eastern San Bernardino County desert © Joel A. Germond Shed Groundsnake Skin, Inyo County
     
Variable Groundsnakes From Outside California
Variable Groundsnake
Variable Groundsnake ground snake
Striped adult, Arizona,
© Gary Nafis, specimen courtesy of Randy Babb
Banded adult, Arizona
© Gary Nafis, specimen courtesy of Randy Babb
Plain brown morph adult,
Presidio County, Texas
ground snake ground snake ground snake
Plain brown morph adult, Travis County, Texas
Variable Groundsnake Variable Groundsnake  
Banded adult, Washoe County, Nevada © Jeremiah Easter  
 
Habitat
Variable Groundsnake Habitat Variable Groundsnake Habitat Variable Groundsnake Habitat
Habitat, rocky wash, 5,500 ft.,
Inyo County mountains
Habitat, White/Inyo Mountains,
Inyo County
Habitat, next to Colorado River, Imperial County desert
Variable Groundsnake Habitat Variable Groundsnake Habitat Variable Groundsnake Habitat
Habitat, Lassen County desert
© Loren Prins
Habitat, Whipple Mountains, San Bernardino County
Inyo Mountains Slender Salamander Habitat Great Basin Fence Lizard Habitat  
Desert Riparian Habitat,
Inyo Mountains, Inyo County
A Groundsnake  was found at a spring in the Kingston Mountains, seen here in the background, in San Bernardino County.
© Steve Bledsoe
 
     
Short Video
  Variable Groundsnake  
  A tiny juvenile Variable Ground Snake is found under a rock in Imperial County.  
     
Similar Snakes
Comparison chart of the 3 subspecies of Chionactis in California, along with the similar sympatric species - Sonora semiannulata, and the similar possibly sympatric species - Chilomeniscus stramineus.

A plain-colored Variable Ground Snake with black on the head is sometimes confused with a Smith's Black-headed Snake - Tantilla hobartsmithi, but the ground snake has a loreal scale, which is not present in Tantilla, and lacks the red coloring on the belly that is found on the black-headed snake.

Variable Groundsnake Smith's Black-headed Snake Mohave Shovel-nosed Snake
Underside of Variable Groundsnake Underside of Smith's
Black-headed Snake
Underside of Shovel-nosed Snake
Description

Not Dangerous (Non-poisonous)  -  This snake does not have venom that is dangerous to most humans.

There are shallow grooves on the outer sides of the rear teeth which indicates that this snake may produce a mild venom, but it is not dangerous to humans.

Size
Adults are typically 8 - 12 inches long (20 - 30.5 cm) with a record length of 18 inches (46 cm).

Appearance
A small snake with a round body, smooth glossy scales, and a head barely wider than the neck.
Color and Pattern
Variable in color and pattern.
Four morphs are found: plain brown, red-striped, black-banded, and red-and-black banded.
These markings do not vary between sexes or change with age.
Often several morphs are found in the same location.

Some examples of the various colors and patterns found in these morphs are:
banded with black and gray or yellowish with or without reddish saddles along the back on the light bands;
solid gray or brown with a darker head;
banded with orange or red and black;
banded with white and black;
banded with pink and gray;
reddish-orange above with gray sides; and
gray with a thin orange stripe along the back.

The underside can be whitish or yellowish with or without dark crossbands.

Life History and Behavior

Activity
Secretive but not uncommon.
Terrestrial, remaining underground in the daytime, surfacing at night or during heavy rains.
Sometimes seen on roads at night, often discovered beneath surface debris, especially rocks.
Diet and Feeding
Eats small invertebrates, including spiders, scorpions, centipedes, crickets, and insect larvae.
Predation
Ground snakes are probably consumed by various vertebrates, including snakes, mammals, and birds, and maybe large lizards, but their predators also include invertebrates: A large Scolopendra heros centipede was observed killing then eating a Ground Snake in Texas. (Herpetological Review 38(1), 2007)
Reproduction

Mating takes place in May and early June.
Eggs are laid underground from late May to August.

Females have been observed laying from 1 - 6 eggs.
Incubation lasts about 60 days.
(Bartlett & Tennant, 2000)

Habitat
Inhabits areas with surface cover and some moisture: grassland, riverbottoms, desert flats, ranchland, sand hummocks, open rocky hillsides with loose soil, sandy washes, dry streambeds, and riparian thickets.

Geographical Range
In California, this species occurs from eastern San Diego county east to the Colorado River, north into the Mojave Desert as far west as 29 palms and Barstow, and north along the eastern slopes of the Sierra Nevada Mountains to Nevada, and farther north in Lassen County.  (The first record from Northeastern California and from Honey Lake Basin in Lassen County was described in Herpetological Review 38(4), 2007, and can be seen in a photo above taken by Loren Prins, who made the discovery.)

Outside California, the species ranges north into Nevada, Oregon, and Idaho, extreme southeast Utah, Arizona, New Mexico, Texas, Oklahoma, Colorado, Arkansas, Missouri, and Kansas, and south into Mexico, including much of Baja California.

Full Species Range Map
(Several subspecies are sometimes recognized, but I don't know their exact ranges outside of California.)

Elevational Range
Occurs from sea level to about 6,000 feet (1,830 m) elevation. (Stebbins & McGinnis, 2018)

Notes on Taxonomy

Several subspecies were once thought to exit based on the different pattern and color morphs found in this species, but when it was observed that several morphs were often found at the same location, this was considered inaccurate.


Cox et al in their April 2018 paper "Synopsis and taxonomic revision of three genera in the snake tribe Sonorini," synonymized genera Chilomeniscus and Chionactis with genus Sonora. They did not discuss common names changes.
If their taxomomy is accepted:

* Sonora semiannulata semiannulata
becomes Sonora semiannulata;
* Chionactis occipitalis becomes Sonora occipitalis;
* Chionactis annulata annulata becomes Sonora occipitalis;
* Chilomeniscus stramineus, where possibly present in California, becomes Sonora cincta.

(Synopsis and taxonomic revision of three genera in the snake tribe Sonorini.
Christian L. Cox, Alison R. Davis Rabosky, Iris A. Holmes, Jacobo Reyes-Valasco, Corey E. Roelke, Eric N. Smith, Oscar Flores-Villela, Jimmy A. GcGuire and Jonathan A. Campbell.
Journal of Natural History, 2018 Vol. 52, Nos. 13-16, 945-988.
https://doi.org/10.1080/00222933.2018.1449912)

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Two subspecies of Sonora semiannulata are recognized since 2000:
S. s. semiannulata
- Variable Groundsnake, and
S. s. taylori
- Southern Texas Groundsnake.


Alternate and Previous Names (Synonyms)

Sonora semiannulata - Western Ground Snake (Stebbins 1966, 1988, 2003, 2012)
Sonora semiannulata - Western Ground Snake (2 subspecies in CA - S. a. isozona; S. a. linearis) (Stebbins, 1954)
S. s. isozona - Bicolored ground snake (Woodbury 1928)
S. s. linearis - Striped ground snake (Van Denburgh 1922)
Sonora episcopa - Texas Ground Snake (Lamprosoma episcopum)

Ringed ground snake
Banded ground snake;
Banded miter snake;
Bicolor ground snake;
Black banded ground snake;
Miter snake;
Pinkish ground snake;
Sonora ring snake;
Striped ground snake;
Vermilion ground snake;
Western earth snake
Vermilion-lined ground snake
Striped earth snake
Vermilion-striped ground snake

Conservation Issues  (Conservation Status)
None
Taxonomy
Family Colubridae Colubrids Oppel, 1811
Genus Sonora North American Groundsnakes Baird and Girard, 1853
Species semiannulata Western Groundsnake Baird and Girard, 1853
Subspecies

semiannulata Variable Groundsnake Baird and Girard, 1853
Original Description
Sonora semiannulata - Baird and Girard, 1853 - Cat. N. Amer. Rept., Pt. 1, p. 117

from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz

Meaning of the Scientific Name
Sonora - region of Sonora - type collected in Sonora, Mexico
semiannulata
- Latin - semi - half and annulata - ringed - refers to the body cross bands which fail to cross the venter

from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz

Related or Similar California Snakes
C. o. annulata - Colorado Desert Shovel-nosed Snake
C. o. occipitalis - Mojave Shovel-nosed Snake
C. o. talpina - Nevada Shovel-nosed Snake
C. stramineus - Variable Sandsnake 
R. l. lecontei - Western Long-nosed Snake

More Information and References
California Department of Fish and Wildlife

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.

Samuel M. McGinnis and Robert C. Stebbins. Peterson Field Guide to Western Reptiles & Amphibians. 4th Edition. Houghton Mifflin Harcourt Publishing Company, 2018.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin Company, 2003.

Behler, John L., and F. Wayne King. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, 1992.

Powell, Robert., Joseph T. Collins, and Errol D. Hooper Jr. A Key to Amphibians and Reptiles of the Continental United States and Canada. The University Press of Kansas, 1998.

Bartlett, R. D. & Patricia P. Bartlett. Guide and Reference to the Snakes of Western North America (North of Mexico) and Hawaii. University Press of Florida, 2009.

Bartlett, R. D. & Alan Tennant. Snakes of North America - Western Region. Gulf Publishing Co., 2000.

Brown, Philip R. A Field Guide to Snakes of California. Gulf Publishing Co., 1997.

Ernst, Carl H., Evelyn M. Ernst, & Robert M. Corker. Snakes of the United States and Canada. Smithsonian Institution Press, 2003.

Wright, Albert Hazen & Anna Allen Wright. Handbook of Snakes of the United States and Canada. Cornell University Press, 1957.

John E. Werler and James R. Dixon. Texas Snakes: Idenification, Distribution, and Natural History. University of Texas Press, Austin. 2004.

Joseph Grinnell and Charles Lewis Camp. A Distributional List of the Amphibians and Reptiles of California. University of California Publications in Zoology Vol. 17, No. 10, pp. 127-208. July 11, 1917.

Conservation Status

The following conservation status listings for this animal are taken from the October 2021 California "Special Animals List" and the October 2021 "State and Federally Listed Endangered and Threatened Animals of California" list, both of which are produced by multiple agencies and available here: https://www.wildlife.ca.gov/Data/CNDDB/Plants-and-Animals. You can check the link to see if there are more recent lists.

If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can go to the NatureServe and IUCN websites to check their rankings.

This snake is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.
Organization Status Listing  Notes
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None
IUCN

 

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