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Hypsiglena torquata

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA DIPSADIDAE

Scientific Name: Hypsiglena torquata
Species Authority: (Gunther, 1860)
Common Name(s):
English Nightsnake, Night Snake
Synonym(s):
Hypsiglena gularis Tanner, 1954
Taxonomic Notes: There have been various arrangements of species within this genus and undoubtedly the current arrangement followed here can be expected to change again in the near future.

The populations on Isla Partida Norte, in the Gulf of California, Mexico are sometimes considered to be a separate species (Grismer 1999, 2000).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Hammerson, G.A., Frost, D.R., Santos-Barrera, G., Vasquez Díaz, J. & Quintero Díaz, G.E.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Least Concern in view of the large and probably relatively stable extent of occurrence, area of occupancy, number of subpopulations, and population size. This species is not threatened in most of its range.

Geographic Range [top]

Range Description: The species' range extends from southern British Columbia, Idaho, Utah, Colorado, and Kansas southward through the southwestern United States to southern Baja California (including Isla Partida Norte, in the Gulf of California) and Guerrero in mainland Mexico, at elevations from near sea level to around 2,650 m asl (8,700 feet) (Stebbins 2003). Reports of occurrences as far south as Costa Rica (e.g., Ernst and Ernst 2003) are incorrect (Savage 2002).
Countries:
Native:
Canada; Mexico; United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by hundreds of occurrences or subpopulations. The total adult population size is unknown but undoubtedly exceeds 100,000. The species occupies a wide range and is locally fairly common. The extent of occurrence, area of occupancy, number of subpopulations, and population size are probably relatively stable. The population in Mexico is stable.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This snake generally inhabits arid and semi-arid plains, flats, canyons, and hillsides, usually rocky, dissected or hilly terrain with sandy or gravelly soils, including desert (e.g., creosote bush, sagebrush), prairie, foothill grassland, chaparral, thornscrub, thornforest, pinyon-juniper woodland, scrubby oak-juniper savanna, mesquite savanna, pine-hardwood woodland, and sometimes moist mountain meadows (Degenhardt et al. 1996, Hammerson 1999, Werler and Dixon 2000, Stebbins 2003). Periods of inactivity are spent under rocks or other surface cover, in crevices, or underground. In Idaho, individuals can be found under surface rocks in spring, but not in summer. It feeds on small amphibians and reptiles, and is an oviviparous species.
Systems: Terrestrial

Threats [top]

Major Threat(s): No major threats to this species have been identified. The habitat generally tends to be unsuitable for human settlement.

Conservation Actions [top]

Conservation Actions: Many occurrences of this species are in national parks and other well-protected areas.

Citation: Hammerson, G.A., Frost, D.R., Santos-Barrera, G., Vasquez Díaz, J. & Quintero Díaz, G.E. 2007. Hypsiglena torquata. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 October 2014.
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