Applying socioendocrinology to evolutionary models: fatherhood and physiology.

Abstract

Owing to humans' unique life history pattern, particularly comparatively short interbirth intervals, early weaning, and prolonged support of multiple dependents, human females have greater reproductive value and higher lifetime fertility, on average, than do their Great Ape counterparts. As hominin females began weaning their young early and "stacking" dependents of various ages, they must have had cooperative allomaternal care partners already in place or been successful at concurrently soliciting help to ensure a high rate of survival of their offspring. Following Hrdy, I define allomaternal care (and its derivatives, such as "allomothers" and "allomothering") as "care from anyone other than the mother," which thus encompasses a wide range of individuals, including fathers. Who the likely allomother candidates mothers were and what form that cooperation took remain intriguing, difficult-to-answer questions, which are limited, in some capacity, by the lines of evidence available to us. Here, I present a framework for the ways in which we can integrate neurobiological-endocrine and social-behavioral data ("socioendocrinology") to contribute to this dialogue in terms of evaluating fathers' roles.