The diet of olive baboons (Papio anubis) in the Budongo Forest Reserve, Uganda

Baboons (genus Papio) are large-bodied, semi-terrestrial monkeys that occupy a diversity of habitats. Across populations, they show wide variation in dietary composition and in their foraging behaviour. Early studies concluded that baboons were generalist feeders, but it is now clear that baboons selectively exploit their environment. The baboon foraging adaptation, in general terms, may be to selectively exploit a wide array of plant foods to satisfy energetic and nutritional needs when faced with a shifting mosaic of possibilities.The variation in diet between baboon populations has been used to investigate the influence of ecology on both diet and foraging behavior, but few such quantitative data have been published for forest- dwelling baboons. Savannah and forest habitats present different ecological conditions and resources to foraging baboons: Tropical forests typically show less dramatic seasonality in comparison with savannah habitats, and so forest-living baboons should experience a wider and potentially more consistent resource base, which may influence both dietary composition and feeding time.

Such data will also be useful for interspecific comparisons. Forest- living baboons may be significant competitors with sympatric chimpanzees (Pan troglodytes) despite contrasts in foraging strategies. While baboons follow a selective–generalist strategy, chimpanzees typically show a reliance on ripe fruit. Baboons may have the advantage in scramble competition where the two species target fruit of the same plant species, as they are better able to digest unripe fruit. There are few data available to test whether such competition occurs. Here, as a preliminary step in investigating potential feeding competition and to broaden the knowledge of baboon foraging strategies, we describe the diet of forest-living olive baboons (Papio anubis) from the Sonso region of the Budongo Forest Reserve, where they live sympatrically with chimpanzees (P. t. schweinfurthii). The diet of these chimpanzees has been well studied, but comparable data for baboons have not been collected.