Adaptive social ties drive post-fission group choice in blue monkeys

Permanent group fissions present rare opportunities for individuals in philopatric groups to select their groupmates, and so by studying post-fission group choice, we can gain insight into how sociality influences decision-making. Our first analysis investigated which social ties influence post-fission group choice in blue monkeys by considering a female's ties to kin, non-kin, the original group's resident male, her risk of infanticide, and her position in the dominance hierarchy in each potential post-fission group. We used nine conditional logit models to analyze how females make this choice, employing alternative ways to quantify social ties to groupmates. We conducted a post-hoc analysis to further investigate which factors influence maternally-related kin to split into different post-fission groups. This study used two datasets, one for the group choice analysis and one for the post-hoc analysis. We also present the R code for the analyses we report in the associated manuscript.