| Species | Hypsiglena torquata Gunther |
| Family | Colubridae (Colubrids) |
| Status | State Monitor |
| State Rank | S3 |
| Global Rank | G5 |
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This is a small snake usually less than 46 cm in total length. The overall appearance is of a spotted snake with dark brown blotches in the neck region. The ground color is light but appears gray, tan, or light brown due to speckles of pigmentation on each scale. Brown blotches run the length of the body. The blotches in the neck region are distinctly larger and vary in appearance. This species has a dark eye stripe from the nostril to the jaw. The upper labial scales are white speckled with brown. The belly scales are pearly white with no markings. Scales are smooth and the mid-body count is 19-21 rows. Pupils are vertical in bright light. This snake is rear fanged and mildly venomous. See Photos Page.
Washington species that are similar in appearance include the Gopher Snake, Rattlesnake and juvenile Racer. Only the Night Snake has both smooth scales and vertical pupils. See Key Features Page.
In Washington, Night Snakes are active from April to October. Mating takes place in the spring, with three to nine eggs laid in June or July each year. Very little is known about the locations selected for egg laying, incubation periods, or the factors that contribute to successful reproduction. Similarly, survival rate, growth rates, and longevity are largely unknown.
In Washington, Night Snakes have been documented from 24 isolated areas of the Columbia Plateau, Eastern Cascades, and Okanogan Ecoregions. See Distribution Map.
For information on the complete range of this species, see NatureServe Explorer.
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. Activity is nocturnal. During the day, individuals can be found under surface objects, generally rocks. However, during prolonged periods of hot weather, they may move deep into talus, rock fissures or rodent burrows. During these warm summer periods, Night Snakes are most easily found on road surfaces at night. Night Snakes eat small lizards and smaller snakes, as well as lizard eggs, frogs, and other small prey. Distribution may be limited by the occurrence of certain lizard prey species.
The status change from S2 to S3 is based on 66 new observations collected between 2003-2004 from 7 Washington Counties. Robert Weaver, a graduate student at Central Washington University, collected 63 of the records. His work indicates that the species is much more common than was previously known but the rank is S3 because of the species association with declining shrub-steppe habitat. Night Snakes are now known to be present in 24 areas, with recent confirmation at 20 of these sites.
The apparent isolation of populations needs to be verified with searches of intervening areas. Food habits, home range, shelter requirements, egg-laying and overwintering habitat associations, and basic demographics need to be investigated. Any sighting that occurs outside the known distribution should be reported to the Washington Department of Fish and Wildlife. Sightings from Okanogan and Walla Walla counties are needed to confirm current presence. Historical records from these counties are from Pateros, McNary Wildlife Recreation Area, and the Prescott area.
The loss of extensive patches of shrub-steppe habitat patches is a primary concern as this habitat is being lost to agricultural conversion and various types of development.
Robert Weaver, a graduate student at Central Washington University in Ellensburg, is nearing completion of his master’s thesis on the ecology of night snakes in Washington. Robert’s work has contributed to knowledge of the distribution of the species in the state. Other important life history, habitat, climate, and diet details will be better understood with the completion of this thesis.
Nussbaum et al. (1983), Stebbins (1985), Storm and Leonard (1995).
Personal Communications: R. Weaver
Hallock, L.A. and McAllister, K.R. 2005. Night Snake. Washington Herp Atlas. http://www1.dnr.wa.gov/nhp/refdesk/herp/
Last updated: February 2005