Like some species of pika (Ochotona) and tree squirrel (Tamiasciurus), the banner-tailed kangaroo rat (Dipodomys spectabilis) is a solitary, philopatric larder-hoarder that practices unisexual territoriality. Seeking to understand how this unusual combination of traits might influence the mating system, we used systematic trapping at mounds (burrows) and spool-and-line tracking to examine male and female visits to each other. Where genetic data exist, unisexual larder-hoarders such as D. spectabilis have been found to be polygynandrous. We asked whether the fact that females sometimes mate with more than 1 male is a passive side effect of imperfect mate defense by males, or whether females actively engage in behaviors that encourage multiple mating. During the nonbreeding season, adults of both sexes were rarely captured at mounds other than their own. In contrast, during the breeding season females as well as males were significantly more likely to be captured away from their home mounds, most often at mounds belonging to adults of the opposite sex. Spool-and-line tracking during the breeding season confirmed these results. Consistent with the expectation that they engage in competitive mate searching, adult males visited adult females' mounds significantly more than expected by chance and without regard to age, size, or relatedness. More surprisingly, adult females exhibited similar behavior, expanding their home ranges and disproportionately visiting the mounds of large adult males during the nights preceding estrus. Increased (and apparently directed) female mobility during the days preceding estrus may serve as a means of shaping the pool of competing mates and is worthy of more attention in this and other, ecologically similar species.