Altruism in humans: an evolutionary approach

In this paper, we review the major findings of almost thirty years of research conducted on the large colony of Japanese macaques (Macaca fuscata fuscata) housed at the Rome zoo. The colony originated from a group of 27 monkeys that was taken as a whole in 1977 from Takasakyiama, Oita prefecture, Japan. Since then, the group has been studied almost continuously. The macaque colony thus represents one of the best studied captive groups of primates in the world. In the first part of the paper, we review the research conducted on the colony, that may be grouped in three related topics: 1) mother-infant relationship; 2) allo-grooming distribution, aggression and competition; 3) demography and life histories. Research conducted in Rome contributed to clarify the causes and consequences of variation in primate mother-infant relationships, the social strategies adopted by primates in cooperative and competitive settings and their cognitive basis, and the demographic consequences of captivity. We compare the results of our research with studies conducted on other groups of Japanese macaques and/or on other primate species. This comparison highlights the consistency of results of studies conducted in captivity, in the wild or on provisioned free-ranging populations. In the second part of this paper, we discuss the benefits and fallacies of zoo research in comparison to field work and the importance of long-term data for animal behaviour studies. We also analyse the link between ethological research and the management of zoo animals. Finally, we consider the interdisciplinary implications of primate behaviour research. We emphasize how the comparative study of nonhuman primates may allow the abstraction of principles that can be profitably applied to the study of human social behaviour and evolution. We exemplify this by examining hypotheses about the relation between social behaviour, brain size and language during human evolution