The evolution of female social relationships in nonhuman primates is influenced by ecological factors, particularly predation risk and food distribution. The ecological model suggests that female gregariousness is determined by the balance between predation risk and food availability. This model explains variations in female-female social relationships, including formal submission signals, dominance hierarchies, and coalitions. It also accounts for female philopatry and dispersal patterns, which are influenced by the strength of competition for resources. However, the model has limitations, as it does not account for infanticide risk and habitat saturation. Alternative models, such as socioecological models, incorporate these factors and provide a more comprehensive explanation of female social relationships. The model predicts that female social relationships vary systematically across primate taxa, with different patterns of dominance, coalition formation, and tolerance. These patterns are influenced by the type of competition for resources, whether within or between groups. The model also highlights the importance of female philopatry and dispersal in shaping social relationships. Despite its strengths, the model has not fully explained all aspects of female social relationships, and additional factors such as infanticide avoidance and habitat saturation may play a role. Overall, the ecological model provides a useful framework for understanding the evolution of female social relationships in nonhuman primates, but further research is needed to refine and expand it.The evolution of female social relationships in nonhuman primates is influenced by ecological factors, particularly predation risk and food distribution. The ecological model suggests that female gregariousness is determined by the balance between predation risk and food availability. This model explains variations in female-female social relationships, including formal submission signals, dominance hierarchies, and coalitions. It also accounts for female philopatry and dispersal patterns, which are influenced by the strength of competition for resources. However, the model has limitations, as it does not account for infanticide risk and habitat saturation. Alternative models, such as socioecological models, incorporate these factors and provide a more comprehensive explanation of female social relationships. The model predicts that female social relationships vary systematically across primate taxa, with different patterns of dominance, coalition formation, and tolerance. These patterns are influenced by the type of competition for resources, whether within or between groups. The model also highlights the importance of female philopatry and dispersal in shaping social relationships. Despite its strengths, the model has not fully explained all aspects of female social relationships, and additional factors such as infanticide avoidance and habitat saturation may play a role. Overall, the ecological model provides a useful framework for understanding the evolution of female social relationships in nonhuman primates, but further research is needed to refine and expand it.