Zhang Peng, Watanabe Kunio
Field Research Centre, Primate Research Institute, Kyoto University, Inuyama, Aichi, Japan.
Am J Primatol. 2007 Oct;69(10):1119-30. doi: 10.1002/ajp.20419.
Japanese macaques on Shodoshima Island habitually form very large rest clusters, in which 50+ or even 100+ individuals huddle together. This behavior is not seen in any other populations of the species. Mean cluster sizes of two groups of Shodoshima monkeys are three and four in summer and 17 and 16 in winter, respectively. A maximum of 137 individuals have been seen to huddle in one cluster. It is difficult to explain the extra large clusters on Shodoshima only as an adaptive behavior against cold, since Shodoshima is relatively warm in the range of habitats for Japanese macaques. Compared with other groups of Japanese macaques, Shodoshima monkeys show: more frequent affinitive interactions, shorter inter-individual distance, more frequent ignoring of exclusion, more frequent aggression, less intense aggression, and more frequent counter-aggression. These characteristics suggest that the Japanese macaques on Shodoshima have relaxed dominant relations. The specific social organization of Shodoshima monkeys may sustain the formation of extra large clusters. Inter-group comparisons suggest that the social structure of Japanese macaques might be highly plastic, and that Shodoshima monkeys have less despotic, more tolerant social relations than typically reported for this species.
小豆岛上的日本猕猴习惯形成非常大的休息群体，其中50多只甚至100多只个体挤在一起。这种行为在该物种的其他群体中未见。小豆岛两组猴子的平均群体规模在夏季分别为3只和4只，在冬季分别为17只和16只。曾观察到多达137只个体挤在一个群体中。仅将小豆岛上这种格外大的群体解释为对寒冷的适应性行为是困难的，因为在日本猕猴的栖息地范围内，小豆岛相对温暖。与其他日本猕猴群体相比，小豆岛的猴子表现出：更频繁的亲和互动、个体间距离更短、更频繁地无视排斥、更频繁的攻击行为、攻击强度较低以及更频繁的反击行为。这些特征表明小豆岛上的日本猕猴的优势关系较为宽松。小豆岛猴子特定的社会组织可能维持了格外大的群体的形成。群体间比较表明，日本猕猴的社会结构可能具有高度可塑性，并且小豆岛猴子的社会关系比该物种通常报道的更不专制、更宽容。
