Feeding Ecology of Guerezas in the Kakamega Forest,Kenya: The Importance of Moraceae Fruit in Their Diet

Eastern black-and-white colobus (Colobus guereza), or guerezas, have long been considered to be one of the most folivorous primates. I conducted a study of the feeding ecology of two guereza groups (T and O) over an annual cycle in the Kakamega Forest of western Kenya. I found that the annual diets of both groups comprised mostly of leaves (T: 48%, O: 57%) though fruit (T: 44%, O: 33%) also accounted for a substantial portion of the diet. In the six months when fruit was most abundant, fruit consumption constituted an average of 58% of T-group's monthly diet and 42% of O-group's monthly diet. In contrast to most previous studies of colobines, in which seeds were the primary fruit item consumed, almost all of the fruit eaten by guerezas at Kakamega consisted of whole fruits. At least 72% of the whole fruits consumed by T-and O-groups were whole fruits from trees in the Moraceae family, which dominates the tree family biomass at Kakamega. Unlike at sites where guerezas consumed fruit primarily when young leaves were scarce, at Kakamega guerezas ate fruit in accordance with its availability and irrespective of the availability of young leaves. My findings demonstrate that guerezas are more dietarily flexible than was previously known, which may help to explain why the species can survive in such a wide variety of forested habitats across equatorial Africa.