Arizona black rattlesnake (Crotalus viridis cerberus)

Abstract

The Arizona black rattlesnake makes its home at higher elevations in Arizona and far western New Mexico. The snake's use of high-altitude habitat and its black coloration as an adult distinguishes it from other subspecies of the western rattlesnake (Crotalus viridis), which prefer lower elevations and range from tan to reddish in color as adults. These physical and habitat differences are also reflected in genetic differences that suggest that the Arizona black rattlesnake may be a new species of rattlesnake. Despite the species's limited range, basic biological information needed to make management decisions is lacking for most Arizona black rattlesnake populations. To address this need, U.S. Geological Survey (USGS) scientists conducted research on the species in Arizona national park units from 2003 to 2005. The research examined relative population abundance, movement patterns, range requirements, dietary habits, and winter and summer habitat. Research in Arizona national parks was made possible through the support of the Western National Parks Association, Tonto National Monument, and the USGS Science Internships for Workforce Diversity Program. Importantly, the park-based research was used to augment a long-term mark-recapture study of the species that has been conducted by USGS biologists at sites near Flagstaff, Arizona, since 1999. USGS researchers were the first to conduct extensive studies of this species in the wild.