The diet and feeding behavior of the black-and-white colobus (Colobus guereza) in the Kalinzu Forest, Uganda

One of the goals for primate feeding ecology is to understand the factors that affect inter- and intra-specific variations. Therefore, a detailed description of basic feeding ecology in as many populations as possible is necessary and warrants further understanding. The black-and-white colobus (Colobus guereza) or guereza is widely distributed in Africa and is one of the well-studied colobines in terms of their feeding; they demonstrate considerable variation in their diets in response to local conditions. We studied the diet of a group of guerezas in the Kalinzu Forest, Uganda, for over 30 consecutive months using behavioral observation (4308 h in total), phenology, and vegetation surveys. A total of 31 plant species were consumed by the study group. This study group was predominantly folivorous; the majority of their feeding time was involved in feeding on young leaves (87%). However, during certain times of the year, fruits and seeds accounted for 45% of monthly feeding time. Young leaves of Celtis durandii were by far the most important food, which constituted 58% of the total feeding records. There was a significant increase in the consumption of fruits and flowers once young leaf availability was low, but their consumption of fruits did not significantly increase even when fruit availability was high. Their monthly dietary diversity increased as the number of available plants with young leaves declined, suggesting that much of the dietary diversity in the study group may be attributable to the young leaf portion of their diet. Our findings may help contribute to a better understanding of the dietary adaptations and feeding ecology of guerezas in response to local environmental conditions

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

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. Feer (1991) 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

ザイール共和国ワンバにおける野生ボノボのオス間関係

要旨ファイルの氏名は"五保部 裕京都大学0048新制・課程博士博士(理学)甲第4881号理博第1338号新制||理||746(附属図書館)UT51-91-S4京都大学大学院理学研究科霊長類学専攻(主査)教授 加納 隆至, 教授 杉山 幸丸, 教授 西田 利貞学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Dietary Choices of a Foregut-Fermenting Primate, Colobus guereza: A Comprehensive Approach Including Leaf Chemical and Mechanical Properties, Digestibility and Abundance

Free-ranging animals make dietary choices that affect their nutritional status and, ultimately, their health and fitness. We investigated food selection by a leaf-eating foregut-fermenting primate, the guereza (Colobus guereza), using multiple criteria, including chemical and mechanical properties, in vitro digestibility and leaf abundance, on the basis of 30 consecutive months of behavioral observations (4308 h in total) of a family group in the Kalinzu Forest, Uganda, as well as vegetation surveys. We noted that leaf toughness may be a proximate cue for the chemical properties of plant foods, especially for protein, which is an important selection factor used by primates. We also found that the in vitro digestibility of plant foods was greatly influenced by the concentrations of fiber and secondary compounds. At a broad level, none of the studied factors, including leaf chemical and mechanical properties, digestibility and abundance, affected whether guerezas consumed specific leaf items. At a more detailed level, however, protein content, digestibility and toughness were related to the percentage of foraging effort that guerezas devoted to specific items in our study site