Ecological studies have shown that female competitive relationships within groups are important in determining individual foraging and reproductive success. Current models predict that clumped food resources influence aggression, yet definitions of clumped resources often include two different concepts: time spent at the resource and distance between resources. In Chapter 1, I conducted an experiment on captive rhesus macaques (Macaca mulatta) to disentangle these two aspects of clumping. Results showed that long food handling time was significantly associated with both contest competition and punishment but that interfood distance was not. Importantly, the study revealed that consumers were aggressive after obtaining food, suggesting that aggression was used as punishment. Consumers who punished were more likely to be high-ranking and to get food in multiple trials. Among punishers, consumers who punished the most were more likely to get the most food. In Chapter 2, I aimed to expand our understanding of dominance relations among female cercopithecines by investigating gray-cheeked mangabeys (Lophocebus albigena) in Kibale National Park, Uganda. Analyses revealed that females formed linear dominance hierarchies, though coalitions were rare. As with captive rhesus macaques, food items with long handling times and potentially high resource values were associated with aggression. Higher-ranking females also spent longer feeding on such foods than lower-ranking females. These results support the hypothesis that food handling time is a behavioral contributor to female dominance hierarchies. In Chapter 3, I used female gray-cheeked mangabeys to test the predictions of biological markets theory. Allogrooming models based on biological markets theory predict that grooming is 'time-matched' within bouts. The models also predict that when female-female contest competition is strong, grooming may be traded for other commodities such as feeding tolerance, and grooming discrepancy between members of dyads is positively related to the distance between their ranks. I found that, among reciprocated bouts, females in all five groups showed time matching. In two groups I also found rank-related discrepancies in grooming, but showing opposite patterns. Consistent with predictions based on biological markets theory, these groups may have been under greater feeding competition, revealed more by adjustments in ranging behavior than increased agonistic rates.