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Heterodon nasicus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA DIPSADIDAE

Scientific Name: Heterodon nasicus
Species Authority: Baird & Girard, 1852
Common Name(s):
English Western Hog-nosed Snake, Western Hognose Snake
Synonym(s):
Heterodon gloydi Edgren, 1952
Heterodon kennerlyi Kennicott, 1860
Taxonomic Notes: Crother et al. (2000) stated that "the nominal races of H. nasicus undoubtedly represent arbitrarily delimited sections of continuous variation," yet Crother et al. (2003) listed Heterodon gloydi as a distinct species, citing comments in Werler and Dixon (2000). However, Werler and Dixon treated gloydi as a subspecies of H. nasicus. Smith et al. (2003) recommended that kennerlyi be recognized as a distinct species, but pending further study, we here recognize gloydi and kennerlyi as subspecies or synonyms of H. nasicus.

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.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Justification:
Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

Geographic Range [top]

Range Description: This species ranges from southern Canada, through the United States to northern Mexico. Its range extends from southern Alberta, southern Saskatchewan, and southern Manitoba southward through primarily the Great Plains region to southeastern Arizona and central Mexico (San Luis Potosi), discontinuously east to Minnesota, Illinois, Missouri, and eastern Texas, and disjunctly west to central Wyoming; reported occurrence in northwestern Colorado need verification (Conant and Collins 1991, Walley and Eckerman 1999, Stebbins 2003). The single record for Arkansas is based on a misidentified specimen (Irwin 2001). Its elevational range is from near sea level to around 2,440 m asl (8,000 feet) (Stebbins 2003).
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 (e.g., see maps in Degenhardt et al. 1996, Hammerson 1999, and Werler and Dixon 2000). The total adult population size is unknown but undoubtedly exceeds 100,000. Historically, local declines probably occurred as a result of habitat destruction. The current trend is probably relatively stable overall, with local declines associated with habitat loss or degradation. Overall, declines are probably less than 10% over 10 years or three generations.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: Its habitat consists of areas with sandy or gravelly soils, including prairies, sandhills, wide valleys, river floodplains, bajadas, mesquite grassland, thornscrub, semi-desert areas, creosote bush desert, open montane woodland, semiagricultural areas (but not intensively cultivated land), margins of irrigation ditches, and sometimes mountain canyon bottoms (Degenhardt et al. 1996, Hammerson 1999, Werler and Dixon 2000, Stebbins 2003). Periods of inactivity are spent burrowed in the soil or in existing burrows. Eggs are laid in nests a few inches below the ground surface (Platt 1969).
Systems: Terrestrial

Threats [top]

Major Threat(s): Conversion of prairie habitat to agricultural use has caused local declines, but overall it is not significantly threatened.

Conservation Actions [top]

Conservation Actions: This species probably is effectively protected in at least several areas of federal, state, and private lands (e.g., national parks and grasslands, state wildlife management areas, large cattle ranches).

Citation: Hammerson, G.A. 2007. Heterodon nasicus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 September 2014.
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