- Common names: midget faded rattlesnake, yellow rattlesnake, faded rattlesnake.
This snake grows to a maximum length of 750 mm (29 1⁄2 in). The smallest gravid female measured was 522 mm (20 1⁄2 in).
The color pattern of this species consists of a pinkish, pale brown, yellow-brown, straw-colored, reddish, or yellow-brown ground color, overlaid with a series of brown elliptical or rectangular dorsal blotches. However, most specimens are gray or silvery. In juveniles, the pattern is distinct, but becomes faded in adults, almost to the point where it is indistinguishable from the ground color.
Found in the United States in the Colorado and Green River basins. This area covers southwestern Wyoming, Utah east of long. 111° West (excluding the southeastern corner) and extreme west-central Colorado. The type locality given is "King's Ranch, Garfield Co., at the base of the Henry Mts [Utah]."
This species possesses the most toxic venom of the C. oreganus/C. viridis group, although apparently considerable variability exists among local populations. It is even one of the most potent venoms found in North America, and according to LD50 studies, the venom is many times more potent than that of an Asiatic cobra. It is characterized by the presence of a presynaptic neurotoxin, referred to as concolor toxin, the amount of which varies in individual snakes.
- List of crotaline species and subspecies
- Crotalus by common name
- Crotalus by taxonomic synonyms
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
- McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- 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, Vol. 21, No.2, pp. 176-189. PDF Archived 2007-09-29 at the Wayback Machine at CNAH. Accessed 3 September 2008.
- Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates. (7th printing, 1985). 1105 pp. ISBN 0-8014-0463-0.
- "Crotalus oreganus concolor". Integrated Taxonomic Information System. Retrieved 11 August 2007.
- Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. 2 volumes. Reprint, University of California Press, Berkeley. ISBN 0-520-21056-5.
- Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- Glenn and Straight, 1977, 1978.
- Glenn and Straight, 1977
- "Archived copy". Archived from the original on 2011-07-16. Retrieved 2010-09-02.CS1 maint: archived copy as title (link)
- Glenn and Straight, 1977, 1990
- Wetstein et al., 1985
- Hubbs, Brian, and Brendan O'Connor. 2012. A Guide to the Rattlesnakes and other Venomous Serpents of the United States. Tricolor Books. Tempe, Arizona. 129 pp. ISBN 978-0-9754641-3-7. (Crotalus oreganus concolor, pp. 32–33.)
- Woodbury, Angus M. 1929. A new rattlesnake from Utah. Bull. Univ. Utah 20 (1).
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