| Research Abstract |
1. Coalition and alliance tactics of adult male chimpanzees were studied. (1) The oldest and adult male of M Group died around March 1993, but his death did not have any influence on the existing male dominance relationships. (2) No change in rank was seen among the 3 highest ranking and 3 lowest ranking males. The relationships among 3 middle-ranking males, however, were unstable and difficult to define. (3) The rivalry between the alpha and beta males was a major factor responsible for the group instability in 1993-94. However, the status of the alpha male was maintained, being supported by the coalition with the gamma male : Social grooming and solicitation of aid in combat were often seen between the alpha and gamma males. On the contrary, these coalitionary moves were rarely seen between the beta and gamma. Moreover, the temporary coalition between the beta and gamma was immediately cancelled when the alpha reconciled with the gamma. (4) The gamma male was occasionally challenged
… More
for status by a young adult male, who was, however, discouraged to continue to do so by the alpha male who intervened in the dispute by attacking the latter one-sidedly. Thus, the coalition between the alpha and gamma was mutually beneficial, being characterized as a reciprocal altruism.
2. Nineteen chimpanzees of M Group died during this study period, 50% of which were killed by influenza. 3. Orphans of 2 to 4 years of age who lost their mothers by influenza were adopted and provided care by an adult female and several adolescent females and males. Thus, most of the orphans including the youngest survived their mothers' death. 4. Gestures, calls, and displays of chimpanzees were audio-visually recorded, which will be analyzed for detailed analysis of social relationships. Samples of blood, bone, muscle, and skeletons of several chimpanzees were obtained, which will be used for DNA typing. A lot of fecal and plant samples were also collected for either parasitological or chemical analyses. Less
|
