Food resources and predation can influence various aspects of the ecology of small mammals, including movement and space-use patterns. We used radiotelemetry to examine experimentally how supplemental feeding and mammalian predator exclusion affected size and exclusivity of hispid cotton rat (Sigmodon hispidus) home ranges. Supplemental feeding had no effect on home-range size, and exclusivity was not influenced by either treatment. However, predator exclusion was associated with increased home-range sizes, indicating a behavioral response to perceived predation risk. We suggest that this behavioral response reflects a trade-off between predation risk and space-use patterns.