The time budgets of all adult and yearling black-tailed prairie dogs in a wild population were measured in 14 separate samples between late April and mid-August 1989. In general, males were more vigilant and fed less than females did. This sex difference was due largely to the behavior of males that had sired offspring; non-fathers behaved more like females. As the summer progressed, prairie dogs spent more time feeding and less time vigilant. The lone exception to this pattern was mothers, who fed less and spent more time vigilant as the summer progressed. Other influences on time allocation produced similar effects for all sex/parental groups: animals were more vigilant while in tall vegetation and in the early morning as opposed to mid-day or evening. Environmental (e.g. weather) and social (e.g. number of other adults and pups present) effects on time allocation were analyzed via multiple regression. Of all potential influences, distance from the nearest burrow seemed to have the most consistent impact on time allocation for all individuals. These results point to strong effects of sex, parental status and environmental context in determining the particular pattern of time allocation observed in an individual prairie dog.