“…At least two processes could leave the mean relatedness among competing females higher than that among competing males. First, males frequently contest extra-group parentage (with non-relatives) [89,92,95,130,131], whereas females rarely do (though see [93]). Second, the strong female philopatry seen in many cooperative mammals [122,123,132] can be expected to exacerbate this sex difference, leaving females frequently contesting within-group reproduction near-exclusively with close relatives [28,45,133,134], whereas males disperse and contest dominance with unrelated males in other groups ( [45,134,135]; though coalitional dispersal can also leave relatives competing post-dispersal).…”