Great Basin night snake (Hypsiglena chlorophaea)

Close up of a desert nightsnake on the ground.
This snake may be confused with a rattlesnake or gopher snake. (B. Hughes)
Category: Reptiles
Common names: Desert Nightsnake or Night Snake
Ecosystems: Shrubsteppe
Vulnerability to climate change (More details)


If you see this species, please share your observation using the WDFW wildlife reporting tool or email us at Be sure to include a photo of the species for verification and location (latitude/longitude coordinates) of your observation. 

The night snake is found throughout the Columbia Basin. This species is identified as important to monitor in the state, based on a distribution that is primarily restricted to shrubsteppe vegetation that has been heavily altered.

Description and Range

Physical description

This is a small, (less than 18 inches in total length) spotted snake with dark brown blotches in the neck region. it has both smooth scales and vertical pupils. 

Ecology and life history

Most night snake occurrences in Washington are from arid areas that support shrub-steppe vegetation, but occurrences in the Leavenworth area are in ponderosa pine forests. Individuals are usually found in rocky areas, but have also been found in sagebrush flats that are not rocky. During the day, individuals can be found sheltering under surface objects, generally rocks. However, during prolonged periods of hot weather, they may move deep into talus, rock fissures or rodent burrows.

In Washington, these snakes are active from April to October. As their common name suggests, they are primarily nocturnal.

Night snakes eat small lizards and smaller snakes, as well as lizard eggs, frogs, and other small prey.

Mating takes place in the spring. Three to nine eggs are laid in June or July each year. Little else is known regarding this snake's reproduction in Washington. Similarly, survival rate, growth rates, and longevity are largely unknown.

Geographic range

In Washington, night snakes have been documented in the Columbia Plateau, Eastern Cascades, and Okanogan Ecoregions. Distribution may be limited by the occurrence of certain lizard prey species. From 2003 to 2004, 66 new observations were made from seven Washington counties by a student as part of his graduate studies. This suggested that the species was more common than was previously known.

For a map of world-wide distribution and conservation status of the Great Basin night snake (a.k.a., "northern desert nightsnake"), check out NatureServe Explorer

Climate vulnerability

Sensitivity to climate change


Great Basin night snake, a small egg-laying largely nocturnal snake that tends to be associated with rocky habitats but has a highly relatively plastic diet though it may take reptiles more frequently, seems relatively robust to historical changes in climate. If any particular sensitivity to climate change exist, it may be linked to dietary specialization of local populations. Uncertainty exist with regard to the impact of climate change on overwintering and oviposition sites, but neither is anticipated to be create particularly great vulnerabilities for this species. Altered fire regimes and invasive weeds have an uncertain likelihood of affecting Great Basin night snakes.

Confidence: Moderate

Exposure to climate change


Confidence: Moderate


This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.

Conservation Threats and Actions Needed

  • Resource information collection needs
    • Threat: Lack of information
    • Action Needed: Research, survey and monitoring are needed to understand the status, distribution and habitat needs of this species.
  • Fish and wildlife habitat loss and degradation
    • Threat: Loss and degradation of suitable shrubsteppe habitat that this species relies upon in Washington.
    • Action Needed: A strategy needs to be developed to make sure enough suitable shrubsteppe habitat is maintained to support viable populations of this snake.
  • Overharvesting of biological resources
    • Threat: Destruction of rattlesnake hibernacula also negatively affects night snakes because they often share hibernacula with rattlesnakes.
    • Action Needed: Environmental education and outreach. Protect snake dens on public lands.


WDFW Publications

Living with wildlife

Snakes are among the most misunderstood of all animals. Of the dozen or so species of snakes found in Washington, only the Western rattlesnake is capable of inflicting a venomous bite, which it seldom does. All snakes are an important part of the natural food chain, eating a variety of prey—from mice and birds to frogs and insects.

Observe snakes, like all wild animals, from a respectful distance. Learn more about living with snakes.