| Research Abstract |
1.Studies of pygmy chimpanzees at Wamba, Zaire (Jul., '90 - Sep., '91)
(1) Mother-son bonds play an important role in the maintenance of the social status of sons.
(2) A sex difference exist in the development of sexual behavior in immatures.
(3) Intergroup interaction patterns vary from mutual tolerance to toal hostility.
(4) Mother's carrying behavior of offspring is concerned with infant's sex, age, developmental stage, and mother's age, rank and nature as well as with the places and situations where they are put.
(5) Vocal patterns are classified into six large categories. It is characteristic of pygmy chimpanzees' vocal communications that vocalizations directed to a single peculiar individual are infreguent.
2. Studied of common chimpanzees at Mahale, Tanzania (Jul. - Dec., '90)
Investigations in inter-male proximity suggest that males are classified into three age classes (i) adolescence, (ii) young adults, (iii) prime and past prime.
3. Studies of common chimpanzees in Uganda
(1) Extensive survey was conducted in six forest blocks in southwestern Uganda. Chimpanzees are low in density in all of them except the Karinzu forest (Feb. and Mar., '92).
(2) Intensive study of nests, grouping patterns, and habitats were carried out in the Karinzu forest (Oct., '92 - Mar., '93). The results will be compared with those from Wamba.
4. Studies of common chimpanzees in Congo (Nov., '92 - Mar., '93)
(1) Extensive surveys in southwestern and northeastern Congo revealed that hunting pressure is a principal factor that affects the density of chimpanzees in Congo.
(2) Extensive studies of nests, grouping patterns and habitats were conducted along the Motaba river. The results will be compared with those from Wamba.
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