Rattlesnake Species in Arizona
The Arizona Game and Fish Department (AZGFD), lists 13 rattlesnake species on its website (www.azgfd.gov). Some species include two or three subspecies. Subspecies are separate populations that are often only slightly different from the other populations of the species. Including the accepted subspecies listed on the AZGFD website, there are 19 kinds of rattlesnakes in the state. Eighteen of them belong to the genus Crotalus. Desert Massasauga, belongs to the genus Sistrurus.
The photograph shows a Southwestern Speckled Rattlesnake (Crotalus mitchelli pyrrhus). It is from the Arizona Herpetological Association website at: www.azreptiles.com.
Counting species is tricky, because not everyone uses the same names. The scientific names, the genus, species, and subspecies are ‘Latinized’ terms that are the same everywhere. Common names are much more variable. For example, AZGFD lists Crotalus viridis viridis as the Green Prairie Rattlesnake, but the Arizona Herpetological Association lists the same species as the Prairie Rattlesnake. The AFOSA wildlife blog provides more information on species names.
Humans are affecting all of Arizona’s rattlesnakes. It is in this regard that subspecies are particularly important. The habitat of one subspecies may be more heavily damaged than the habitat of another subspecies. Thus, it is not helpful to list an entire species as needing protection when only one subspecies is in jeopardy. AZGFD lists six rattlesnake species and subspecies as the most affected by human impacts. They are the Arizona Ridge-Nose, Desert Massasauga, Green Prairie, Hopi, New Mexico Ridge-nose, and the Western Twin-spotted.
In 2011 the Center for Snake Conservation (CSC) began holding snake counts. Volunteers conduct two types of counts, by automobile and on foot. Everyone can take part. The CSC provides instructions, tool kits, and manages the counts. Learn more and sign up for the fall or spring count at the CSC website.
AZGFD maps show seven species and subspecies of rattlesnakes might occur in the Agua Fria River Basin. They are the Arizona Black, Black-tailed, Mojave, Sidewinder, Southwestern Speckled, Tiger, and Western Diamondback. The Western Diamondback is the most dangerous. It is the largest, and will stand its ground and defend itself when threatened. The AFOSA wildlife blog provides a checklist of all of Arizona’s snakes.