Comparative Reproductive Energetics of Human and Nonhuman Primates

Primates as a group exhibit high reproductive costs, departing in numerous ways from expectations derived from other mammals. Yet, there is also substantial life-history variation within primates that affects the costs of producing offspring and how these costs are distributed over time. Whereas general phylogenetic and allometric trends are well established, issues regarding the mechanisms that regulate energy allocations remain unresolved. This review examines reproductive energetics across primates, placing them in context with other mammals and comparing how reproductive processes change as body and brain size increase. The three major stages of reproduction (conception, pregnancy, and lactation) are examined along with the reproductive adaptations that facilitate them: breeding seasonality, placental formation, breast milk production, body fat, and communal breeding. Throughout, this review examines how comparative primate energetics can help illuminate the unique adaptations that allow humans to produce extraordinarily costly offspring at an unexpectedly high rate.