Animals may respond to seasonally changing environments with physiological and behavioral strategies. Whereas migration is a behavioral strategy used by many taxa, it may not be an option for small mammals. However, small mammals can seasonally vary the area of habitat in which they are active. The striped mouse Rhabdomys pumilio in the semiarid Succulent Karoo of South Africa lives in a seasonal environment, characterized by hot, dry summers with low food abundance and cold, wet winters, followed by high food abundance in spring. We radio tracked a total of 28 females during the 2004 dry season, the following breeding season in spring, and the following dry season in 2005 and tested the prediction that females shift their home ranges in relation to food availability. Females shifted their home ranges from an area characterized by evergreen succulent shrubs in the vicinity of a dry riverbed in the dry season to sandy areas that were characterized by new plant growth of annuals in spring. Home ranges during the breeding season in spring had a higher percentage of annuals than dry season home ranges measured in spring. Female home range size increased during the breeding season. We suggest that female striped mice shift their home ranges seasonally to gain access to protein-rich young plant material, which is important for breeding.