The development of infant Mαcαcα thibetαnα was studied at Mount Emei, China, and compared to that of other macaque species. It was found that there are many common features in the process of infant socialization in species of the genus Mαcαcα: mothers play an important and active role, other group members influence the infants’ development to a greater or lesser extent and play is a major activity in the life of infants. Some differences were found to exist, however, between macaque species. These included differences in maternal care behaviour such as ‘len’, leaving time and weaning time. Paternal behaviours were also found to vary within and among species. Tibetan macaque males care for infants extensively, and they may use infants as an agonistic buffer. The natural and social environment may also influence differences between macaque species in infan