Frequent insectivory by two guenons (Cercopithecus lhoesti and Cercopithecus mitis) in the Kalinzu Forest, Uganda

I investigated the feeding ecology of l'Hoest's monkeys (Cercopithecus lhoesti) and blue monkeys (Cercopithecus mitis) in the Kalinzu Forest, Uganda. Although forest guenons are generally thought to be frugivores or folivores, these two guenons spent a large proportion of their time feeding on invertebrates. The l'Hoest's monkey and the blue monkey spent as much as 66 and 50% of their time on insectivory, respectively. These proportions of time spent on invertebrate feeding are higher than those reported elsewhere for forest guenons. L'Hoest's monkeys mainly utilized the area near the ground for invertebrate feeding, while blue monkeys utilized the area around 20 m above the ground. It seemed that guenons have an ability to change their diet according to the environment.