The significance of fibrous foods for Kibale Forest chimpanzees

ABSTRACT

Four categories of plant food dominated the diet of chimpanzees in Kibale Forest; Uganda non-fig tree fruits; fig tree fruits; herbaceous piths and terrestrial leaves. Fruit abundance varied unpredictably; more among non-figs than figs. Pith intake was correlated negatively with fruit abundance and positively with rainfall; whereas leaf intake was not influenced by fruit abundance. Piths typically have low sugar and protein levels. Compared with fruits and leaves they are consistently high in hemicellulose and cellulose; which are insoluble fibres partly digestible by chimpanzees. Herbaceous piths appear to be a vital resource for African forest apes; offering an alternative energy supply when fruits are scarce