Data from: Female affiliation and status in semi-free-ranging chimpanzees

Objectives: Sex differences in social behavior and status are pervasive
across primates and other mammals. In the wild, chimpanzees (Pan
troglodytes) exhibit many sex-typed behaviors: adult female chimpanzees
exhibit lower aggression, are subordinate to adult males, and also are
generally less social than males. This pattern is thought to partly
reflect the energetic constraints (e.g. feeding competition) that wild
female chimpanzees face. Materials and Methods: We test the drivers of sex
differences in chimpanzee behavior by examining a semi-free-ranging
African chimpanzee sanctuary group where individuals are provisioned, an
environment that should relax ecological constraints on socializing. Using
two years of focal observations on a group with 45 chimpanzees (17 males,
28 females), we examined sex differences in social proximity, grooming,
aggression, coalition formation, and dominance. Results: In contrast to
patterns in wild chimpanzees, we found that males and females in this
population exhibited comparable rates of affiliative behavior. Males
engaged in more aggressive behavior overall than females, as in the wild.
However, females were equally likely to aggress either sex, and a high
proportion of female aggression involved coalitions. Finally, David’s
scores revealed that a few of the adult females outranked some of the
lower-status adult males. Discussion: These findings show that sex
differences in chimpanzee social behavior are partially flexible, and
females may show more affiliation, cooperation, and higher status when
ecological conditions are favorable. More generally, some forms of female
power can emerge even in a species with strong sex biases in behavior
favoring male affiliation and status.