| Project/Area Number |
02041046
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Institution | The University of Kyoto |
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Principal Investigator |
KURODA Suehisa Assistant Professor, Faculty of Science, The University of Kyoto, 理学部, 助手 (80153419)
黒田 末寿 (1992) 京都大学, 理学部, 助手
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| Co-Investigator(Kenkyū-buntansha) |
ルフィン A オコ コンゴ共和国経済森林省自然保護局, 主任研究員
OKO Rufin Antoin Chief Researcher, Division of Fauna and Flora Conservation, Ministry of Economy
オコ ルフィン A. コンゴ共和国, 森林省・自然保護局, 主任研究員
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 1992: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1991: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1990: ¥3,500,000 (Direct Cost: ¥3,500,000)
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| Keywords | Sympatric Apes / Chimpanzee / Gorilla / Tropical Forst / Congo / Interspecies Relation / Peaceful Coexistence / Nich Separation / ツェゴチンパンジ- / ロ-ランドゴリラ / 生態 / 社会構造 / 熱帯雨林 / ドキ=ヌアバレ保護区 / ツエゴチンパンジ- / ドキ保護区 / 熱帯多雨林 |
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| Research Abstract |
Sympatric chimpanzees (Pan t. troglodyte) and gorillas (Gorilla g. gorilla) inhabit the Ndoki Forest in high densities (2.5-3.5 head/km2, 2.5-3.0 head/km2 respectively). Socionomic sex ratio of chimpanzees thought to be forming two unit-groups, is 0.8. This is the highest value among chimpanzee population studied thus far. This chimpanzees are frugivorous, but prey upon animals as like other populations. A hunting attempt with the use of tool by a female was observed. They also make and use two kind of tools for one goal of termite-eating (Macroterms sp.). Sticks are used to perforate termite mounds and probes are used to fish for termites by inserting these into the holes made by sticks.
The size of gorilla unit-groups varies from 2 to 40. Gorillas feed on both herbs and fruits. Their fruit-eating seems depend upon the availability of fruits in their habitat. Although their major food in the fruiting season is fruits, when they became scarce, gorillas rapidly change to herbs. Herbs suc
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h as Marantacese and Hydrocharis are consumed through out the year, and these seem to be the key plans that sustain the population in this area. They also feed on termites, but they are different species (Cubiterms sp.) from those that chimpanzees obtain with tools.
Co-feeding by chimpanzees and gorillas in a fig tree was observed 4 times. They did not seem to be bothered by each others presence, although they did not approach to within less than 6-7m of each other. Although their food repertoires are largely overlap with each other, we have no evidence of antagonistic interactions between these apes. On the contrary, they separate their niches in animal and herbaceous foods. It is interesting that both kinds of food contain much protein. However, their niche separation on protein is not a result of competition, because gorillas have never been observed to hunt animals in any situation. Gorillas can also eat the same termite species as chimpanzees, if they like, because this termites can often be found in large numbers moving on the ground. This niche seperation seems to have occurred because of other factors. Less
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