Polyspecific associations and niche separation of rain-forest anthropoids in Cameroon, West Africa

A 19 month field study of rain-forest anthropoids at Idenau and several other rain forests, and a similar 15 month study at Southern Bakundu were conducted in Cameroon, West Africa. The study areas and their primate fauna are described. Polyspecific associations of primates were temporary, but not random, some species occurring together more frequently than others, and with statistical significance. Seasonal environmental factors affecting the composition of polyspecific cercopithecid associations are described. Interspecific social behaviour was infrequent and hybridization rare; instances of each are described. Observations on vertical stratification, habitat preference, seasonal movements and food habits indicated that all these factors contribute to niche separation among five sympatric species of rain-forest Cercopithecus. The major predator of anthropoids in Cameroon is man. To a much lesser extent the Crowned hawk-eagle, Stephanoaëtus coronatus (Linnaeus) preys on Cercopithecus species. It is suggested that polyspecific associations, by increasing the effective group size, give advantages in food location and avoidance of predators without increasing interspecific competition for food and competition between males for females.