Sonora Semiannulata – Western Ground Snake

Sonora Semiannulata - Western Ground Snake information

Sonora semiannulata, the western ground snake is a small nonvenomous snake found in the Western United States and in Mexico. It can have various body colorations with strong colors. It is also referred to as the common ground snake or the variable ground snake, due to its variable body coloration.


The color of the western ground snakes varies between individual specimen. The basic color of the body can be yellow-brown, light brown with a pink shade as well as orange-colored. There are populations with a dark band on the neck and other populations with several bands along their body. The belly is usually light grey, white or cream-colored.

One of the morphs that appears quite often is an orange-colored snake with several black lateral blotches along its body. This appearance is also reflected in its specific name “semiannulata” which is Latin for “half-ringed”.

Sonora Semiannulata - Western Ground Snake information
An orange western ground snake with the characteristic black half-rings. Photo: Peter Paplanus

However, the snake can also be uniformly colored. Snakes without any patterns often have lighter colors on their sides.

Variable Ground Snake (Sonora semiannulata semiannulata) in Arkansas
A uniformely-colored western ground snake. Photo: Peter Paplanus


Sonora semiannulata is a small snake that reaches an average length of 8-16 inches (20-40 cm). Some individuals can reach a length of up to 19 inches (50 cm).

Hunting Behavior and Habitat

The western ground snake lives in lowlands as well as in mountainous areas of up to 6,000 feet (1830 m) above sea level. It can be found in various arid habitats such as rocky areas, semi-dry deserts, prairies and mixed forests. It is a nocturnal snake that rests hidden away or in the shade throughout the day. They feed mainly on small invertebrates such as spiders and centipedes.

Variable Ground Snake found in missouri orange snake with black crossbands patterns
A western ground snake found in Missouri. Photo: Flickr


The western ground snake is a small nonvenomous snake. It is absolutely harmless to humans. Due to its small head and teeth, it will most likely not succeed to bite through human skin.

Western ground snake range in the USA

The western ground snake can be found in Mexico as well as in the Southwestern United States in the following states: Arizona, Nevada, California, Colorado, Kansas, Missouri, Arkansas, New Mexico, Oklahoma, Oregon, Idaho, Texas, and Utah.

Scientific classification of Sonora semiannulata

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Reptilia
  • Order: Squamata
  • Suborder: Serpentes
  • Family: Colubridae
  • Genus: Sonora
  • Species: Sonora semiannulata

Subspecies of Sonora semiannulata

Currently, two valid subspecies of the western ground snake are recognized:

  • Sonora semiannulata semiannulata
  • Sonora semiannulata taylori
Sonora Semiannulata – Western Ground Snake

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