ニホンザル自然群の社会構造に関する1例 : 箕面谷のB群について

抄録

In the Minoo Valley about 15 km. north of Osaka City, there live two natural groups of Japanese Macaque, Macaca fuscata fuscata. The larger group is called the Minoo-A group and the smaller the Minoo-B group. This paper deals with the results of our study on the social organization of the latter group, which has some characteristic features differing from those of other groups hitherto surveyed. The Primates Research Group, to which we belong, has already clarified the social organization of four different wild groups of Japanese Macaque in different localities of Japan including the Minoo-A group, and the present study represents the 5th example. As Table 1 shows, the Minoo-B group consists of 17 members belonging to 7 different social status. 2 individuals, Nasio and Zuku, comprises the axis of the group and share the leadership, younger Nasio being the chief-male and old Zuku the headfemale. Adult female, young female, infant and baby are the other 4 status. Besides these there is another interesting status. 2 females, especially young Anzu behaved as if they were young males and played the status role of common males in other normal groups. These 2 females seem to complement the social deficit due to the absence of common males in this unusual macaque group. Besides the two groups, a male party is found which consists of 5 younger males and follows after the B-group keeping some distance apart from the latter. According to KAWAMURA'S preceding observations, certain historical processes as follows are responsible for this situation. Formerly Nasio was the leader of an independent male party, when the chief-male of the B-group was occupied by a full adult male named Ata. In the later part of 1955,however, Ata disappeared and his status was replaced by Nasio who came from the male party. Members of the male party other than Nasio thereafter abandoned their own nomadism and became the follower associated to the B-group. Sexual relationship between the Minoo-B group and the associated male party exhibited several features as yet unknown in any other group so far studied. The group of females often approached the male party in a very open manner or tried to tempt the males to her group. Even in such cases, the chief-male Nasio showed no rage to the females, unlike most chiefs of other groups who found impudent females. A particular type of females' calling, which we registered as (K'), was found to be a stereotyped behavior on their approach to the males, rarely known in other groups. A violent series of homosexual behavior between Anzu and Momo was observed, Anzu playing the typical role of a male. Part of the series is recorded in Table 2. These facts should be of importance in the socio-ecological comparison among groups of Japanese Macaque.