Ecology of the Grand Canyon rattlesnake (Crotalus viridis abyssus) in the Little Colorado River Canyon, Arizona

We studied movement behavior, activity range size, habitat use, and diet of the Grand Canyon rattlesnake (Crotalus viridis abyssus) in the Little Colorado River Canyon (Arizona) by capturing 13 rattlesnakes and equipping 9 with radio-transmitters. On average, snakes moved 45 m per movement and 26 m per day; males moved longer distances than females, but movement frequency was not significantly different between sexes. Unlike some other populations of C. viridis, Grand Canyon rattlesnakes exhibited low directionality of movements. Activity range size ranged from <4 to >30 ha among individuals, and the corridor-like nature of the canyon bottom resulted in elongate activity ranges. Prey species of rodents were common in each of 4 subhabitats on the study site, and snakes appeared to be dietary opportunists, eating a variety of rodent and lizard prey. Snakes preferentially used riparian areas and avoided floodplains. Talus and upland mesquite habitats were used in rough proportion to their availability. Differential use of subhabitat may result from thermoregulatory constraints and from variation in predictability of rodent prey.