The Diurnal Primate Fauna and Population Densities of Tschego Chimpanzees in Southwestern Congo

Hiroshi IHOBE


An extensive two-part survey on the diurnal primate fauna and population densities of tschego chimpanzees (Pan t. troglodytes) was carried out in southwestern Congo from November 1992 to February 1993. The first half of the survey was conducted in the Regions of Niari and Lekoumou. In this area, the occurrence of Pan t. troglodytes and Cercopithecus pogonias was confirmed by direct observations. The occurrence of Gorilla g. gorilla, Mandrillus sphinx, Cercopithecus cephus and C. nictitans was confirmed by the indirect evidence. Local people informed me of the presence of Cercocebus albigena, C. torquatus and Miopithecus talapoin, although they were not confirmed directly. The second half of the survey was carried out at Dimonika in the Region of Kouilou. Pan t. troglodytes and Cercopithecus cephus were directly observed. Peer (199l) has reported the occurrence of Gorilla g. gorilla, Mandrillus sphinx, Cercocebus albigena, Cercopithecus pogonias and C. nictitans, but no evidence was obtained for their presence. The chimpanzee population densities, calculated from nest counts in the survey, were higher near the border of Gabon and in the eastern part of the Region of Lekoumou than other areas. This difference in population densities seemed to be due to differences in hunting pressure by humans. The overall population density of chimpanzees in southwestern Congo was lower than that in the Nouabale-Ndoki National Park in northern Congo, but roughly the same as in Equatorial Guinea, and in Gabon.

Key Words: Diurnal primate fauna; Pan t. troglodytes; Population density; Southwestern Congo.

African Study Monographs, 16: 35-44 (1995)

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