Ecological studies on food conditions and cognitive ability of Japanese macaques over food

该项目旨在阐明单个日本猕猴如何识别野外食物的分布，以及每个个体如何将这些知识用作觅食策略。对居住在日本屋久岛岛暖温带森林中的习性良好(未提供食物)的日本猕猴进行了实地研究。采用焦点取样法和扫描取样法收集各季节(春、夏、秋、冬)的活动节律、取食时间预算、个体日数范围、旅行路线、食物补丁选择、停留时间和个体间关系等数据。将这些数据与直线样线法测量的果实物候期进行了分析。结果表明，野生日本猕猴(Macaca Fuscata Yakui)根据优质食物(水果或昆虫)的可获得性，使用两种觅食模式(目标导向和机会主义)。在猕猴结果期(秋冬)经常观察到目标导向觅食，此时猕猴形成一个凝聚力的群体，长途旅行，连续访问特定的果树。机会性觅食通常发生在非结实季节(冬春)，此时它们分散到不同的食物中，不仅食物条件，而且个体的性别、年龄或社会地位都会影响觅食策略的选择。个体觅食模式反映了日本猕猴的生活史和社会认可度。以目标为导向的觅食可能已经演变为一种介于摄食和繁殖之间的最佳策略，这一策略受到个体社会认知的强烈影响。

This project aims to clarify how individual Japanese macaque recognize the distribution of foods in the wild and how each individual uses these knowledge as foraging strategies. Field studies have been conducted on the well habituated (non-provisioned) Japanese macaques inhabiting the warm-temperate forest at Yakushima Island, Japan. Data were collected by focal-sampling and scan-sampling methods on activity rhythm, feeding time budget, individual day range, travel route, choice of food patch, duration of visit, and inter-individual relationships in each season (Spring, Summer, Autumn and Winter) . These data were analyzed in relation to phenology of fruit measured by the line-transect methods. The results suggest that the wild Japanese macaques (Macaca fuscata yakui) use two foraging patterns (Goal-oriented and Opportunistic) according to the availability of high-quality foods (fruits or insects) . The goal-oriented foraging is observed frequently during the fruiting period (Autum-winter) , when macaques form a cohesive group, travel long distance and continuously visit the particular fruiting trees. The opportunistic foraging is usually observed during the non-fruiting season (winter-spring) , when they disperse to forage diversed food items individually.Not only food conditions but also sex, age or social status of each individual influence the choice of foraging strategies. Individual foraging patterns reflect life history and social recognition of Japanese macaques. The goal-oriented foraging may have evolved as an optimal strategy between feeding and reproduction, which are strongly influenced by individual social recognition.