Food selection by western gorillas (G.g. gorilla) in relation to food chemistry

Samples of stems, leaves, shoots and fruit (N=36) from lowland, African rain forest are analyzed for nutrients, digestibility and digestion-inhibiting substances. Plants from which the samples are drawn are all important in the diet of western gorillas, large generalist herbivores in coastal Cameroon. Many of the plants are common in the early succession following disturbance to the forest. Analysis of food chemistry in relation to food preference indicates that lignin, digestibility and crude protein are the most significant factors in food selection for western gorillas at this site. Food chemistry of western gorillas is compared to food chemistry of mountain gorillas in the montane forest of East Africa. Foliage consumed by western gorillas contains more condensed tannin than does foliage consumed by mountain gorillas. The greater content of condensed tannin in the leaves consumed by western gorillas is related to the greater representation of woody plants in the western diet.