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This study identified the dietary composition of the arboreal tree hyrax Dendrohyrax arboreus, a rare, poorly known, forest mammal, in three eastern Cape forests. Fecal analysis showed D. arboreus to be a selective browser with an average of 7.2, 12.4, and 9.5 species of plants in the diet at the Pirie, Alexandria and Springmount forests, respectively. The economically important yellowwood Podocarpus falcatus was the principal dietary item at Pirie forest, whereas the principal dietary items at Alexandria forest were Schotia latifolia, Cassine aethiopica, and Eugenia capensis zeyheri. Principal food items at Springmount forest were S. latifolia and Euclea natalensis. Dietary preferences could not be explained by dietary abundance of plants, and appear to be related to the complex energetics of arboreal folivory. This delicate energy balance, together with the fact that the tree hyrax is a selective feeder, has implications for the selective removal of plant species from forests of the eastern Cape.
Key words: Dendrohyrax arboreus, arboreal folivore, diet, fecal analysis, South Africa
Mammals in the mass range of arboreal folivores (<15-20 kg) are predicted to face severe problems meeting energy requirements from fibrous diets (Cork and Foley, 1991), because retention time of the gastrointestinal tract varies as a fractional power of body mass (W^sup 0.28^) and smaller animals have lower digestive efficiencies (McNaughton and Georgiadis, 1986). Folivores must be able to use fiber as their main source of digestible energy or maintain a sufficiently high intake of foliage from digestion of contents of the cells. Because many arboreal folivores live close to the limit of their energy budgets, they have certain characteristics in common (Eisenberg, 1978). These include decreased speed of locomotion, small size of home ranges and litters, a relatively dense pelage, and heatconserving mechanisms. Herbivores feeding primarily on woody foliage of plants also have significantly lower metabolic rates (Mattson, 1980). Folivores often have antipredator strategies that depend on crypticity and they seldom live in large groups and frequently are nocturnal. They also have well-developed communication systems for localizing their positions relative to one another (Eisenberg, 1978).
The tree hyrax Dendrohyrax arboreus arboreus is a small (1.5-3.35 kg-Kingdon, 1971) forest mammal residing in the indigenous forests of the eastern Cape and Kwazulu-Natal, South Africa. Elsewhere in Africa the species occurs along...