Crotalus viridis

Crotalus viridis

Common names: prairie rattlesnake, western rattlesnake, plains rattlesnake, more.
Crotalus viridis is a venomous pitviper species native to the western United States, southwestern Canada, and northern Mexico. Two subspecies are recognized, including the nominate subspecies described here.


This species commonly grows to more than 100 cm in length. The maximum recorded size is 151.5 cm (Klauber, 1937). In Montana, specimens occasionally exceed 120 cm in length; Klauber (1972) mentioned that the species reaches its maximum size in this region.

Common names

Prairie rattlesnake, western rattlesnake, plains rattlesnake, black rattler, common rattlesnake, confluent rattlesnake, Great Basin rattlesnake, large prairie rattlesnake, Missouri rattlesnake, rattlesnake of the prairies, spotted rattlesnake.

Geographic range

Found in North America over much of the Great Plains, from southern Canada south through the United States to northern Mexico. In Canada it occurs in Alberta and Saskatchewan; in the USA in eastern Idaho, Montana, North Dakota, South Dakota, Wyoming, Nebraska, Colorado, Kansas, Oklahoma, Texas, New Mexico, extreme eastern Arizona; in Mexico in northern Coahuila and northwestern Chihuahua. Its vertical range from 100 m near the Rio Grande River to over 2,775 m elevation in Wyoming.

Wright and Wright (1957) and Klauber (1997) both mention Utah as within the range of this species, including maps showing it confined to the extreme southeastern part of the state.

The type locality is described as "the Upper Missouri" (Valley, USA). An emendation was proposed by Smith and Taylor (1950) to "Gross, Boyd County, Nebraska."

Conservation status

This species is classified as Least Concern (LC) on the IUCN Red List of Threatened Species (v3.1, 2001). Species are listed as such due to their wide distribution, presumed large population, or because it is unlikely to be declining fast enough to qualify for listing in a more threatened category. The population trend is stable. Year assessed: 2006.


Subspecies Taxon author Common name Geographic range
C. v. nuntius Klauber, 1935 Hopi rattlesnake The United States from northeastern and north-central Arizona, from the New Mexican line to Cateract Creek, including the Little Colorado River basin, the southern section of the Apache Indian Reservation, the Hopi Reservation, and the Coconino Plateau from the southern rim of the Grand Canyon to U.S. Highway 66 in the south.
C. v. viridis (Rafinesque, 1818) Prairie rattlesnake North American Great Plains from the Rocky Mountains to long. 96° W. and from southern Canada to extreme northern Mexico, including southwestern Saskatchewan, southeastern Alberta, Idaho in the Lemhi Valley, Montana east of the higher Rockies, southwestern North Dakota, west, central and extreme southeastern South Dakota, western Iowa, central and western Nebraska, Wyoming except for the Rockies, Colorado, central and western Kansas, Oklahoma, extreme southeastern Utah, northeastern Arizona, New Mexico, western and southwestern Texas, northeastern Sonora, northern Chihuahua, northern Coahuila.


The taxonomic history of this species is convoluted. Previously, seven other C. viridis subspecies were also recognized, including abyssus, caliginis, cerberus, concolor, helleri, lutosus and oreganus. However, in 2001 Ashton and de Queiroz published a paper describing their analysis of the variation of mitochondrial DNA across the range of this species. Their results agreed broadly with those obtained by Pook et al. (2000). Two main clades were identified, east and west of the Rocky Mountains, which they argued were actually two different species: on the one hand C. viridis, including the conventional subspecies viridis and nuntius, and on the other C. oreganus, including all the other traditional subspecies of C. viridis. The authors retained the names of the traditional subspecies, but emphasized the need for more work to be done on the systematics of C. oreganus.

See also


Further reading

  • Ashton KG, de Queiroz A. 2001. Molecular systematics of the Western Rattlesnake, Crotalus viridis (Viperidae), with comments on the utility of the D-Loop in phylogenetic studies of snakes. Molecular Phylogenetics and Evolution 21(2):176-189.

External links

Search another word or see crotalus viridison Dictionary | Thesaurus |Spanish
Copyright © 2015, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature