| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Akiko Okinawa University, Department of Welfare and Culture, Associate Professor (80369206)
HOSAKA Kazuhiko Kamakura Women's University, Faculty of Child Studies, Associate Professor (10360215)
NAKAMURA Michio Kyoto University, Department of Zoology, Assistant Professor (30322647)
ZAMMA Koichiro Japan Monkey Centre, Research Fellow (50450234)
佐々木 均 酪農学園大学短期大学部, 教授 (60105252)
藤田 志歩 岐阜大学, 応用生物科学部, 特別研究員
橋本 千絵 京都大学, 霊長類研究所, 助手 (40379011)
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| Budget Amount *help |
¥30,420,000 (Direct Cost: ¥23,400,000、Indirect Cost: ¥7,020,000)
Fiscal Year 2006: ¥9,750,000 (Direct Cost: ¥7,500,000、Indirect Cost: ¥2,250,000)
Fiscal Year 2005: ¥10,010,000 (Direct Cost: ¥7,700,000、Indirect Cost: ¥2,310,000)
Fiscal Year 2004: ¥10,660,000 (Direct Cost: ¥8,200,000、Indirect Cost: ¥2,460,000)
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| Research Abstract |
Development, learning, propagation, and acquisition rate of locality-specific behavior patterns, and rate of cultural fixation of innovative patterns have been investigated for M group chimpanzees at Mahale, Tanzania. Ant-fishing begins at age 3, with its skill improving at age 5, and become perfect around age 7-8. Individuals begin grooming-hand-clasp with mothers at age 5, subsequently with adult females and finally with adult males around age 9. The slow development of grooming-hand-clasp compared with cognitively-demanding tool-using is remarkable. Many cultural patterns have been confirmed for most weaned chimpanzees. However, sex and age differences also exist Some females do not perform leaf-clipping courtship, while all the males do. Shrub-bend courtship is shown by only males, and throw-splash and metal-wall-drumming by only adult males. Such innovative patterns as mouth-holding of infant and belly-slapping display spread to at least one other individual, whilst nasal probe ne
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ver spread. Innovative patterns including belly-slapping, digging stick for water and nipple press continue for 3-10 years on an individual basis, but likely perish without becoming a culture. However, the number of youngsters performing innovative behaviors such as leaf-sponge/spoon and muzzle-rubbing with a branch have gradually increased recently, which may be an example of fashion based on social learning. Chimpanzees often peer other individuals engaged in grooming, eating, baby caring, and self-medicating. Peering may be one of the mechanisms through which youngsters acquire traditions. The tendency for younger individuals peer older ones indicates the possible function of social leaning, but the fact that adult individuals also sometimes peer suggests another function. Youngsters get a traditional menu from eating food left over by relatives and playmates. Some patterns such as leaf-clipping seem to be common local cultures. Rapid habituation to humans suggests the socialization process by which newcomers acquire M-group's attitudes to humans. M-group chimpanzees neither predate nor scavenge aardvarks and leopards. Despite this conservative nature, they have adopted a new food culture of eating yellow baboons. DNA analyses based on excretions show that alpha males inseminated more than half of infants and that male outside of the group had none. Father-offspring comparison of behavior will be an interesting challenge. A study of Y chromosome polymorphisms indicates that males of M group and a neighboring group have common male ancestors. We have collected field materials including: 750 DV tapes, 10, 000 still photos, 220 field notes, 3 chimpanzee skeletons, 900 tubes of insects, 112 urine and 139 fecal samples. Less
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