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. 2 Volumes. University of California Press, Berkeley, California. pp.
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: Friday 05 December 2025 15:58 CT