I studied the ecology and behavior of ringtails (Bassariscus astutus) in juniper (Juniperus monosperma) woodland on the Sevilleta National Wildlife Refuge in central New Mexico. Average home-range sizes of ringtails (males 462 ha, females 94 ha, 95% fixed kernel) were among the largest reported to date. Females moved least in summer and most in autumn, but males showed no seasonal trend in movements. The average stay in a single den was 1.3 days. I found no effect of the closeness of approach of the den observer on the distance moved between successive dens. Ringtails used a variety of den settings: rocks, trees, shrubs, rocks and shrubs, and holes in the ground. Males used trees and rocks more and shrubs less than females. In summer and autumn, ringtails used rocks more and shrubs less than expected, and in winter ringtails used rocks less and shrubs and holes in the ground more than expected. There was no tendency to reuse certain types of dens, and 31.6% of dens were reoccupied at least once. Most ringtails died before the age of 4 due to predation, resulting in an annual survival rate of 0.375. Contrary to the popular conception that ringtails require open, permanent water for survival, 16 of 18 ringtail home ranges had no water source within them, and no ringtail was observed in the vicinity of water. Latrines of ≥2 scats contained 89.4% of scats found. As measured by frequency of occurrence in scats, ringtails consumed primarily fruits, followed by arthropods, mammals, birds, and reptiles, Many arthropod prey were venomous or chemically defended. Average weights were 1.0 kg for males and 0.9 kg for females.