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Home/Species/ Short-headed Gartersnake

Thamnophis brachystoma

(Cope, 1892)

Short-headed Gartersnake

G4Apparently Secure Found in 3 roadless areas NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.104011
Element CodeARADB36010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicendemic to a single nation
KingdomAnimalia
PhylumCraniata
ClassReptilia
OrderSquamata
FamilyColubridae
GenusThamnophis
Other Common Names
Short-headed Garter Snake (EN) Shorthead Garter Snake (EN)
Concept Reference
Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The garter snakes: evolution and ecology. University of Oklahoma Press, Norman. xx + 332 pp.
Conservation Status
Review Date2006-09-05
Change Date1998-07-10
Edition Date2006-09-05
Edition AuthorsHammerson, G.
Threat ImpactMedium
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences21 - 300
Rank Reasons
Small range in New York and Pennsylvania (and introduced in Ohio); population densities maybe lower than historical numbers, but believed to be maintaining a steady population density; several introduced populations have become established; apparently secure.
Range Extent Comments
The native range includes southwestern New York and northwestern Pennsylvania, mainly in the unglaciated portions of the upper Allegheny River drainage, at elevations of 270 to over 700 meters (Ernst and Barbour 1989, Rossman et al. 1996, Ernst and Ernst 2003). This species is introduced and established at Pittsburgh and apparently also in Butler, Clearfield, and Erie counties (e.g., Lethaby, 2004, Herpetol. Rev. 35:73), Pennsylvania, in south-central New York (Conant and Collins 1991), and in Youngstown, Mahoning County, Ohio (Novotny, 1990, Herpetol. Rev. 21:42). In New York, this snake is restricted to the Allegheny River drainage in Chatagua, Cattaraugus, and Allegheny counties and two isolated (possibly introduced) areas at Horseheads straddling the Susquehanna and St. Lawrence river drainages, Chemung County (Bothner 1986).
Occurrences Comments
This species is represented by a large number of occurrences (subpopulations). Bothner (1976) mapped 69 records in New York and Pennsylvania and five questionable records. McCoy (1982) mapped 73 records in 11 counties from Pennsylvania. Hulse et al. (2001) mapped 70+ collection sites in Pennsylvania plus 9 additonal locations with established introductions.
Threat Impact Comments
In some areas the preferred habitat has disappeared as old farms have been developed or abandoned and reforested (Bothner 1986). It has been suggested that Thamnophis sirtalis may be encroaching on the range of T. brachystoma in some reforested areas (Bothner 1986), but whether or not this poses a threat independent of that associated with habitat change is unknown.

This species becomes established easily when introduced in suitable areas in urban settings outside the natural range (McCoy 1982). However, it disappears from areas that have undergone intensive development.
Ecology & Habitat

Diagnostic Characteristics

Differs from THAMNOPHIS SIRTALIS in usually lacking a longitudinal series of black spots between the dorsal and lateral stripes. Differs from THAMNOPHIS BUTLERI in having a shorter head and 17 scale rows at mid-body (vs. usually 19).

Habitat

Habitats include old fields, meadows, pastures, forest edges, and other open herbaceous fields, often in areas close to water or wetlands; this snake scarcely penetrates wooded areas; it can be found active or basking on the ground or in stone piles or under debris (Rossman et al. 1996, Hulse et al. 2001, Ernst and Ernst 2003). Introduced populations are well established in urban settings. Hibernating individuals have been found underground on a steep rocky slope.

Ecology

Commonly aggregates under cover objects.

Reproduction

Mating occurs in spring. Litters of 5-14 young are born late July-September (Behler and King 1979), mostly in August. Sexually mature in second year. Mature females do not produce young every year.
Terrestrial Habitats
Forest EdgeGrassland/herbaceousOld field
Other Nations (1)
United StatesN4
ProvinceRankNative
New YorkS3Yes
OhioS3Yes
PennsylvaniaS4Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial development——High (continuing)
1.1 - Housing & urban areas——High (continuing)
7 - Natural system modifications——High (continuing)
7.3 - Other ecosystem modifications——High (continuing)

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Roadless Areas (3)
Pennsylvania (3)
AreaForestAcres
Allegheny FrontAllegheny National Forest7,430
CornplanterAllegheny National Forest2,929
Tracy RidgeAllegheny National Forest9,034
References (18)
  1. Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.
  2. Bier, Charles W. Western Pennsylvania Conservancy. Pittsburgh, PA. Personal communication.
  3. Bothner, R. C. 1976. Thamnophis brachystoma. Cat. Am. Amph. Rep. 190.1-190.2.
  4. Bothner, R. C. 1986. A survey of the New York state populations of the short-headed garter snake, <i>Thamnophis brachystoma</i> (Cope) (Reptilia: Colubridae). Unpublished report for the New York State Endangered Species Unit. Contract no. Coo1340.
  5. Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles. 3rd ed. Society for the Study of Amphibians and Reptiles. Herpetological Circular No. 19. 41 pp.
  6. Conant, R. and J. T. Collins. 1991. A field guide to reptiles and amphibians: eastern and central North America. Third edition. Houghton Mifflin Co., Boston, Massachusetts. 450 pp.
  7. Conant, R., and J. T. Collins. 1998. A field guide to reptiles and amphibians: eastern and central North America. Third edition, expanded. Houghton Mifflin Co., Boston, Massachusetts. 616 pp.
  8. Crother, B. I. (editor). 2008. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth edition. Society for the Study of Amphibians and Reptiles Herpetological Circular 37:1-84. Online with updates at: http://www.ssarherps.org/pages/comm_names/Index.php
  9. Crother, B. I. (editor). 2012. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 7th edition. SSAR Herpetological Circular 39:1-92.
  10. Crother, B. I. (editor). 2017. Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. 8th edition. SSAR Herpetological Circular 43:1-104. [Updates in SSAR North American Species Names Database at: https://ssarherps.org/cndb]
  11. Ernst, C. H., and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.
  12. Ernst, C. H., and R. W. Barbour. 1989b. Snakes of eastern North America. George Mason Univ. Press, Fairfax, Virginia. 282 pp.
  13. Harding, J. H. 1997. Amphibians and reptiles of the Great Lakes region. University of Michigan Press, Ann Arbor. xvi + 378 pp.
  14. Hulse, A. C., C. J. McCoy, and E. Censky. 2001. Amphibians and reptiles of Pennsylvania and the Northeast. Comstock Publishing Associates, Cornell University Press, Ithaca. 419 pp.
  15. Lawson, R. 1987. Molecular studies of thamnophiine snakes: 1. The phylogeny of the genus <i>Nerodia</i>. J. Herpetology 21:140-157.
  16. McCoy, C. J. 1982. Amphibians and reptiles in Pennsylvania. Carnegie Museum of Natural History Special Publication No. 6.
  17. Novak, P. Associate Zoologist, New York Natural Heritage Program, Wildlife Resources Division, Department of Environmental Conservation, Latham, NY
  18. Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The garter snakes: evolution and ecology. University of Oklahoma Press, Norman. xx + 332 pp.