THE CENTER FOR NORTH AMERICAN HERPETOLOGY

Reptilia    Squamata (part-snakes)    Crotalidae  

Eastern Black-tailed Rattlesnake
Crotalus ornatus Hallowell, 1854
KROH-tah-lus — or-NAY-tus

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: 2024.02.20.10.09.00)
Download GeoJSON polygon range file: - 0.08 MB

Province/State Distribution:
United States: New Mexico Texas

Taxonomic Etymology:
Known for its striking dorsal pattern.
Crotalus — From Greek: κρόταλον (krotalon) = “rattle” or “castanet”. This refers to the rattle at the end of the tail, a defining characteristic of rattlesnakes. So Crotalus means “rattler.”
ornatus — From Latin ornatus, meaning “decorated,” “ornate,” or “adorned”

First instance(s) of published English names:
Black-tail Rattlesnake (Crotalus molossus: 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); Dog-faced Rattlesnake (Crotalus molossus: Stejneger, Leonhard H. 1895. The poisonous snakes of North America. Annual Report of the United States National Museum 1893(2):337-487); Black-tailed Rattlesnake (Crotalus molossus: Schmidt, Karl Peterson and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. C.P. Putnam and Sons, New York. 365pp.);

Taxon Links:

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

Selected References:
1854 Hallowell, Edward. Notices of new reptiles from Texas. Proceedings of the Academy of Natural Sciences of Philadelphia 7:192-193
1940 Gloyd, Howard K. The rattlesnakes, genera Sistrurus and Crotalus. Chicago Academy of Sciences Special Publication 4(1):1-266
1956 Klauber, Laurence M. Rattlesnakes. Their Habits, Life Histories, and Influence on Mankind. Volume 2. University of California Press, Berkeley, California. 1476pp.
1972 Klauber, Laurence M. Rattlesnakes. Their Habits, Life Histories, and Influence on Mankind. 2 Vols. 2nd ed. University of California Press, Berkeley and Los Angeles. pp.
2012 Anderson,Christopher G. and Eli Greenbaum. Phylogeography of northern populations of the Black-Tailed Rattlesnake (Crotalus molossus Baird and Girard, 1853), with the revalidation of C. ornatus Hallowell, 1854. Herpetological Monographs 26(1):19-57
2024 Myers, Edward A., Rhett M. Rautsaw, Miguel Borja, Jason Jones, Christoph I. Grünwald, Matthew L. Holding, Felipe Grazziotin, and Christopher L. Parkinson. Phylogenomic discordance is driven by wide-spread introgression and incomplete lineage sorting during rapid species diversification within rattlesnakes (Viperidae: Crotalus and Sistrurus). Systematic Biology syae018:

THE CENTER FOR NORTH AMERICAN HERPETOLOGY — Accessed: Tuesday 28 April 2026 11:39 CT