THE CENTER FOR NORTH AMERICAN HERPETOLOGY

Reptilia    Squamata (part-snakes)    Natricidae  

Black-necked Gartersnake
Thamnophis cyrtopsis (Kennicott, 1860)
THAM-noh-fiss — sir-TAWP-sis

SSAR 9th Edition Comments:
 There are no current SSAR comments for this taxon.

Range maps are based on curated specimens and provided gratis by CNAH.
(Created by Travis W. Taggart; Version: 2025.08.21.15.08.25)
Download GeoJSON polygon range file: - 0.76 MB

Province/State Distribution:
United States: Arizona Colorado New Mexico Oklahoma Texas Utah

Taxonomic Etymology:
Named for its curved head markings.
Thamnophis — From Greek thamnos (θάμνος), “bush” or “shrub,” and ophis (ὄφις), “snake.” The name means “bush-snake” or “shrub-snake,” likely referring to the habitats where these snakes are commonly found.
cyrtopsis — From Greek kyrtos (κυρτός), “curved” or “arched,” and opsis (ὄψις), “appearance.” The name means “curved appearance,” referring to the distinctive curved black markings on the neck or side of the head.

First instance(s) of published English names:
Couch's Garter Snake (Eutaenia cyrtopsis: Yarrow, Henry C. 1882. Check list of North American Reptilia and Batrachia with catalogue of specimens in U. S. National Museum. Bulletin of the United States National Museum (24):1-249); Black-necked Garter Snake (Thamnophis cyrtopsis: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.); Black-necked Garter Snake (Thamnophis cyrtopsis cyrtopsis: Schmidt, Karl P. 1953. A Check List of North American Amphibians and Reptiles. 6th Edition. University of Chicago Press, Chicago, Illinois. 280pp.);

Taxon Links:

  
Catalog of American Amphibians and Reptiles
  
The Reptile Database
  
NatureServe
  
iNaturalist
  
GenBank
  
USGS - Nonindigenous Aquatic Species Database

Selected References:
1860 Kennicott, Robert. Descriptions of new species of North American serpents in the Museum of the Smithsonian Institution, Washington Proceedings of the Academy of Natural Sciences, Philadelphia 12:328-338
1908 Ruthven, Alexander G. Variations and genetic relationships of the garter-snakes. Bulletin of the United States National Museum (61):1-201
1972 Baker, Robert J., George A. Mengden, and James J. Bull. Karyotypic studies of thirty-eight species of North American snakes . Copeia 1972(2):257-265
1980 Webb, Robert G. Thamnophis cyrtopsis. Catalogue of American Amphibians and Reptiles (245):1-4
1994 De Queiroz, Alan and Robin Lawson. Phylogenetic relationships of the garter snakes based on DNA sequence and allozyme variation. Biological Journal of the Linnean Society 53:209-229
2002 de Queiroz, Alan, Robin Lawson, and Julio A. Lemos-Espinal. Phylogenetic relationships of North American garter snakes (Thamnophis) based on four mitochondrial genes: How much DNA sequence is enough?. Molecular Phylogenetics and Evolution 22(2):315-329

THE CENTER FOR NORTH AMERICAN HERPETOLOGY — Accessed: Friday 05 December 2025 15:54 CT