Biogeographic variation in the diet and behaviour of Cercopithecus mitis

Primate species are characterised by variation in foraging behaviour and dietary composition across their geographic range. Here we examine how ecological conditions account for variation in the behavioural ecology of a widespread arboreal guenon, Cercopithecus mitis. Although substantial variation existed in time budgets, group size, home range and day journey length, clear biogeographic patterns were not apparent. In contrast, dietary variation was correlated with underlying climatic conditions. Temperature seasonality, which tends to increase with latitude, was significantly positively related to the proportion of fruit in the diet and negatively related to the proportion of animal matter. Both dietary components were 'preferred' foods, with the variability between populations reflecting the availability of different food types across their geographic range. Although we found no significant relationships between climate and the proportion of leaves in the diet, the ability for C. mitis to vary its diet to include a diversity of food types, and to incorporate a significant proportion of leaves when preferred sources are scarce, likely underpins its ability to survive across such a large distribution.