No evidence for female kin association, indications for extragroup paternity, and sex‐biased dispersal patterns in wild western gorillas

Characterizing animal dispersal patterns and the rational behind individuals’ transfer choices is a long-standing question of interest in evolutionary biology. In wild western gorillas (Gorilla gorilla), a one-male polygynous species, previous genetic findings suggested that, when dispersing, females might favor groups with female kin to promote cooperation, resulting in higher-than-expected within-group female relatedness. The extent of male dispersal remains unclear with studies showing conflicting results. To investigate male and female dispersal patterns and extra-group paternity, we analyzed long-term field observations, including female spatial proximity data, together with genetic data (10 autosomal microsatellites) on individuals from a unique set of four habituated western gorilla groups, and four additional extra-group males (49 individuals in total). The majority of offspring (25 of 27) were sired by the group male. For two offspring, evidence for extra-group paternity was fo...