Evolution of Non-Maternal Care in Primates

This special issue comprises papers on the proximate, intermediate and ultimate evolutionary causes of non-maternal infant care (allocare) across the range of primate taxa in which this unusual mammalian behaviour has evolved. Why should non-maternal care of infants, or allocare, have evolved in certain primate taxa? What stimulates non-mothers to care for infants? How are such behaviours mediated physiologically? The papers in this edited issue reflect a range of approaches to these questions, including a detailed field study of the spectral tarsier of Sulawesi, for which details of infant care behaviour were previously unknown, and comparative analyses of field data on cercopithecines and callitrichids. Hormonal correlates of allocare are investigated in callitrichids, and similarities and differences in the involvement of particular hormones across birds, rodents and primates are reviewed. The possibility that contrasting natal colouration of the infants of some primate species may serve to attract allocare is explored, as is a theoretical model for the evolution of care specifically from the infants' fathers. A variety of possible life history and ecological correlates of allocare is tested across primates, demonstrating that allocare enables mothers to increase their reproductive rates. Allocare is an unusual feature among primates, as it is in other mammals, and understanding how and why it has evolved requires a range of approaches, and synthesis of findings, as demonstrated in this issue. Of interest to primatologists, socioecologists, anthropologists, zoologists and endocrinologists.