An integrated understanding of paternal care in mammals: lessons from the rodents

Abstract

AbstractMammalian paternal care is rare, and often considered synonymous with social monogamy. Numerous hypotheses have been proposed to explain the evolution and function of paternal care in mammals, many assuming that males are important for offspring survival, with accompanying costs and benefits to fathers and mothers. Most hypotheses are taxon‐centric, focusing primarily on three mammalian orders. Consequently, there is no definitive ‘one size fits all’ hypothesis that adequately explains the evolution of mammalian paternal care. Here, we review both proximate (ontogeny, mechanisms) and ultimate (adaptive significance, evolution) questions to provide an integrated perspective of paternal care, focussing on the rodents. Firstly, we describe the behavioural machinery, and then the neuroendocrine, genetic end environmental factors that regulate and modulate paternal care. We suggest that the behavioural machinery of parental care is conserved in both males and females, although parental care is regulated in a sex‐ and species‐specific manner. Secondly, we provide hypotheses for the evolution and function of paternal care. In contrast to previous studies, we consider seven adaptive hypotheses that explore the possibility of paternal care benefiting the offspring, mothers and/or fathers. We also consider three constraints hypotheses. We suggest that paternal care does not have to incur a survival benefit to offspring to evolve. Instead, the combined benefits to fathers, mothers and offspring should out‐weigh the costs to fathers of providing care. Our suggestions for integrating proximate and ultimate explanations for why and how male rodents provide paternal care are applicable across taxa. Integrating these explanations is complicated because the adaptive consequences are context and species‐specific. Therefore, future research should integrate these approaches within and between a wide array of taxa.