Chimpanzee fathers bias their behaviour towards their offspring.

Carson M Murray,Elizabeth V Lonsdorf,Emily E Wroblewski,Margaret A Stanton,Anne E Pusey

doi:10.1098/rsos.160441

Abstract

Promiscuous mating was traditionally thought to curtail paternal investment owing to the potential costs of providing care to unrelated infants. However, mounting evidence suggests that males in some promiscuous species can recognize offspring. In primates, evidence for paternal care exists in promiscuous Cercopithecines, but less is known about these patterns in other taxa. Here, we examine two hypotheses for paternal associations with lactating mothers in eastern chimpanzees (Pan troglodytes schweinfurthii): paternal effort, whereby males associate and interact more with their own infants, and mating effort, whereby males invest in mothers and offspring for mating privileges. We found that fathers associated more with their offspring than they did with non-kin infants, particularly early in life when infanticide risk is highest. Additionally, fathers and their infant offspring interacted more than expected. Notably, association between fathers and mother–infant pairs did not predict the probability of siring the mother's next offspring. Our results support the paternal effort, but not the mating effort hypothesis in this species. Chimpanzees are one of the most salient models for the last common ancestor between Pan and Homo, thus our results suggest that a capacity for paternal care, possibly independent of long-term mother–father bonds, existed early in hominin evolution.

Highlights

Promiscuous mating by females is thought to limit paternity certainty for males, and paternal care owing to the potential cost of investing in unrelated offspring who provide no direct fitness benefit in return [1]
A long-held assumption is that promiscuity reduces the likelihood of paternal behaviour, as males may accidently invest in unrelated infants [1]
A growing body of work in Cercopithecine primates raises the intriguing question about whether paternal kin recognition is the ancestral state in this subfamily (e.g. [50,51,52]), but work 8 in other Cercopithecines and other old world primates is important to increase our understanding of these patterns at higher taxonomic levels

Summary

Introduction

Promiscuous mating by females is thought to limit paternity certainty for males, and paternal care owing to the potential cost of investing in unrelated offspring who provide no direct fitness benefit in return [1]. In yellow baboons, fathers intervened on behalf of their offspring in conflicts [6], and father’s presence during the immature period predicted accelerated offspring maturation [8] Work in another baboon species found paternal effects on offspring outcomes; for example, Huchard et al [9] reported that juvenile desert baboons accessed richer food patches when in close proximity to their fathers. These patterns suggest that males in some promiscuous primate species recognize their offspring and support a paternal effort hypothesis for male behaviour towards offspring and their mothers

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Results

Conclusion