EPOW - Ecology Picture of the Week

Arizona Black Rattlesnake (Crotalus cerberus), Family Vipiridae
northern Arizona

Explanation:   Watch your step!  Coaxed from its cool dark hiding place among rock outcrop dens in a secret location south of Flagstaff, Arizona, this beautiful viper is ready to defend itself.

This is an Arizona black rattlesnake -- little-known and nearly unstudied, except for a team of intrepid herpetologists led by Erika Nowak who have been analyzing the few known populations in northern Arizona since 1998.  The study is focusing on recapture data using pit-tagging surveys to analyze population size.  View a slide series here of the team's rattlesnake study and "roundup."

The color pattern of Arizona black rattlesnakes 
is most unique, and beautiful.
(Click for larger image)

The ventral scales, too, are strikingly marked.
(Click for larger image)

View a brief movie of the capture of an Arizona black rattlesnake here (2MB MPG file) ... and a brief movie of the "noisy end" of one in the hand here (1MB MPG file) (both files © Bruce G. Marcot).

Arizona black rattlesnakes reach a length of 20-48 inches (51-122 cm) and are found in central and northern Arizona and New Mexico.  They are quite varied in coloration (compare to western rattlesnake, which we explored in a previous EPOW).  

Note the typical "keeled" scales, characteristic
of vipirid snakes including rattlesnakes.
(Click for larger image)

Arizona black rattlesnakes have been only recently changed from being viewed as a subspecies of western rattlesnake (Crotalus viridis cerberus) into its own full species, thanks to mitochondrial DNA analysis.  It seems to be the most primitive of the viridis complex, perhaps signifying it as the origin of the other viridis subspecies.  

And this is but one of an amazing array of 85 rattlesnake species and subspecies found in the New World (North America through South America).  

Acknowledgment:  Many thanks to Erika Nowak for allowing me to accompany her field research expedition, and to team members Justin Schofer, Carol Chambers, and others from whom I learned much about this seldom-seen species.  

Information:  Schuett, G. W., E. M. Nowak, and R. A. Repp. 2002. Crotalus cerberus (Arizona Black Rattlesnake): diet and prey size.  Herpetological Review 33(3):210-211.