The evolution of female social relationships in nonhuman primates

Abstract

Considerable interspeci®c variation in female social relationships occurs in gregarious primates, particularly with regard to agonism and cooperation between females and to the quality of female relationships with males. This variation exists alongside variation in female philopatry and dispersal. Socioecological theories have tried to explain variation in female-female social relationships from an evolutionary perspective focused on ecological factors, notably predation and food distribution. According to the current``ecological model'', predation risk forces females of most diurnal primate species to live in groups; the strength of the contest component of competition for resources within and between groups then largely determines social relationships between females. Social relationships among gregarious females are here characterized as Dispersal-Egalitarian, Resident-Nepotistic, Resident-Nepotistic-Tolerant, or Resident-Egalitarian. This ecological model has successfully explained di erences in the occurrence of formal submission signals, decided dominance relationships, coalitions and female philopatry. Group size and female rank generally a ect female reproduction success as the model predicts, and studies of closely related species in di erent ecological circumstances underscore the importance of the model. Some cases, however, can only be explained when we extend the model to incorporate the e ects of infanticide risk and habitat saturation. We review evidence in support of the ecological model and test the power of alternative models that invoke between-group competition, forced female philopatry, demographic female recruitment, male interventions into female aggression, and male harassment. Not one of these models can replace the ecological model, which already encompasses the between-group competition. Currently the best model, which explains several phenomena that the ecological model does not, is a``socioecological model'' based on the combined importance of ecological factors, habitat saturation and infanticide avoidance. We note some points of similarity and divergence with other mammalian taxa; these remain to be explored in detail.

Comparative analysis of the role of olfaction and the neocortex in primate intrasexual competition

“…Thus, among primates, diet ultimately determines the social organization of females within a group (Janson, 1988;Janson and van Schaik, 1988;van Schaik, 1989;Isbell, 1991;Sterck et al, 1997). Access to food resources can be attained through scramble competition for dispersed resources or contest competition for concentrated, defendable resources (Janson and van Schaik, 1988).…”

Triadic awareness predicts partner choice in male–infant–male interactions in Barbary macaques

“…De Waal 1986;van Hooff and van Schaik 1994), to increase fitness (Silk et al 2003;Silk 2007a, b;Silk et al 2009;Schülke et al 2010) and contributes to the stability and cohesion of the group (e.g. Sterck et al 1997;Lehmann et al 2007). It has been suggested that the challenges of social life might drive the evolution of complex social knowledge, so-called triadic awareness, that is, knowledge about the relationships among other individuals.…”

Social structures in Pan paniscus: testing the female bonding hypothesis

“…Socio-ecological models predict that when females migrate, bonds between them will be less developed than in species where females are philopatric (Wrangham 1980;Van Schaik 1989;Sterck et al 1997). These female bonded species are characterised by ''highly differentiated networks of social relationships within groups, based on grooming, aggression and other interactions'' (Wrangham 1980, p. 263).…”