The owl-faced guenon is thought to be largely terrestrial, spending most of its time on the ground (4) (6). It has two peaks of daily activity; one in the early morning, and then again in the late afternoon or evening (7). Living in small groups with a single male (2), the owl-faced guenon is apparently territorial, but avoids serious conflicts with neighbouring groups (7). This omnivorous monkey feeds on fruit, insects and leaves (2). Its fairly large incisors are perfect for biting into fruit, and the flatter molars are suited to crushing and grinding hard seeds. It also possesses cheek pouches, the advantages of which are twofold: in areas where competition for fruit is intense, the monkey can grab as much food as possible before being supplanted by another hungry monkey, and at the same time, enzymes in the saliva help break down toxic compounds in unripe fruits and seeds stored in the pouches (8).