We measured potential advantages of living singly as contrasted to in male-female pairs in a free-living population of the prairie vole (Microtus ochrogaster) in a high food habitat. Whereas adult females survived longer when living in a pair than when living singly, adult males survived longer when single and wandering throughout the study site than when paired. Estimated total number of offspring produced that survived to adulthood and became reproductive was similar for paired females (0.32 female and 0.36 male offspring/female) and females living singly (0.34 female and 0.25 male offspring/female). There was no correlation between the proportion of unpaired adult males in the population and either adult population density, adult sex ratio, or proportion of females that were living singly. These results support the hypothesis that living in pairs evolved in the original low food habitat of the prairie vole and represents a basic behavioral trait that is retained regardless of food resources in the habitats now occupied.