Capuchins live in groups of 10 to 40 members. These groups consist of related females and their offspring, as well as several males. Usually groups are dominated by a single male, who has primary rights to mate with the females of the group, though the white-headed capuchin groups are led by both an alpha male and an alpha female. Mutual grooming as well as vocalization serves as communication and stabilization of group dynamics. These primates are territorial animals, distinctly marking a central area of their territory with urine and defending it against intruders, though outer areas may overlap.