Abstract
The age-sex composition of provisioned groups of Japanese monkeys (Macaca fuscata yakui) was investigated along the Anbo Road in the southeast of Yakushima island, Japan. The monkeys had been provisioned on an irregular basis by tourists passing through by car or bus. Group size, age-sex composition and socionomic sex ratio were no different from those of purely wild groups of monkeys in Yakushima, as reported by Maruhashi (1982). However, the proportion of females with infants of 7-9 months old in a group on the Anbo Road was estimated to be higher than that for non-provisioned groups. The reason for this could be improvement of nutritional condition as a result both of provisioning by tourists, and of feeding on high quality herbs planted on large, artificial slopes which flank several sections of the Anbo Road.
