Friend or foe: reconciliation between males and females in wild chacma baboons

Abstract

Male aggression towards females is a common and often costly occurrence in species that live in bisexual groups. But preferential heterosexual relationships are also known to confer numerous fitness advantages to both sexes-making it of interest to explore how aggression is managed among male-female dyads through strategies like reconciliation (i.e., post-conflict affiliative reunions between former opponents). In this study, we build on traditional PC-MC, time-rule, and rate methods to validate a novel methodological approach that tests for the presence and form of reconciliation between male and female wild chacma baboons (Papio ursinus). We show that heterosexual opponents exhibit friendly post-conflict reunions, further demonstrating that reconciliation occurs almost exclusively between males and pregnant/lactating females who form tight social bonds. Such 'friendships' represent stable associations offering proximate and ultimate benefits to both parties-mainly improving (future) offspring survival. This aligns our findings with the Valuable Relationship Hypothesis, which predicts rates of reconciliation to increase with the fitness consequences of the opponents' bond. Moreover, patterns concerning the initiative to reconcile reveal that males are as likely as females to initiate reconciliation, suggesting that males play a heretofore underappreciated role in maintaining heterosexual friendships. Beyond proposing a multivariate methodological technique applicable to other long-term observational datasets, the present research illuminates how male-female aggression in promiscuous societies may be mitigated via relationship-repair strategies like reconciliation, the balance in those efforts between partners shedding new light on the mutual investment in such bonds.

Mechanisms of equality and inequality in mammalian societies

“…both philopatric; mixed sexes; omnivore (most food not defendable) coalitions (N,R) [73] tolerated co-feeding limited to kin at playbacks [74] post-conflict reconciliation [75] olive baboon (P. anubis) females philopatric; mixed sexes; omnivore (most food not defendable) coalitions (N) [54]; social skills in infants linked to maternal care [76]; maternal sociality predict infant growth and reproduction [77] mothers experiencing more adversity had increased glucocorticoid levels and reduced offspring survival [78] mutual feeding tolerance by males of males and females sexes of different ages [60] cultural shift from competitive to peaceful troop [79] post-conflict reconciliation [67,80] yellow baboon (P. cynocephalus) females philopatric; mixed sexes; omnivore (most food not defendable) coalitions (N, R, CH) [54];…”

“…food, tools, land) transfer (material wealth)food sharing and adoption of non-kin c revolutionary coalitions and peacekeepingfairness—inequity aversion d conflict resolution (forgiveness/reconciliation) e chimpanzee ( Pan troglodytes spp. )male philopatry; mixed sexes; omnivore (most food not defendable)coalitions (N, R, CH) [54]; maternal presence positively influenced offspring muscle mass [55] and survival [56]maternal rank and ‘stress’ during gestation correlated with offspring stress physiology [57]intergenerational transfer of stone tools (hammers and anvils) [58] and natal community [59]meat-sharing among kin and non-kin; some enforcement via aggression [60,61]males join forces to overthrow the α male [62,63]inequity aversion to unequal pay (food) paradigm [64]post-conflict reconciliation [65–67]bonobo ( Pan paniscus) male philopatry; mixed sexes; omnivore (most food not defendable)coalitions (N, R) [54], but they also promote tolerance; maternal presences associated with increased mating, particularly by low and mid-ranking males [68] mutual tolerance; co-feeding promotes social interactions [69–71]females join forces to protect themselves from harassment by males [72]inequity aversion to unequal pay (food) unclear [64]post-conflict reconciliation [67]chacma baboon ( Papio ursinus) both philopatric; mixed sexes; omnivore (most food not defendable)coalitions (N,R) [73] tolerated co-feeding limited to kin at playbacks [74] post-conflict reconciliation [75]olive baboon ( P. anubis )…”