Collared mangabey  (Cercocebus torquatus)

Collared mangabeys live in large groups of 12 to 23 individuals, with several adult males within each group (2). Loud cackles and alarm barks echo across the forest as the mangabeys keep in contact with the members of their group and signal their position to neighbouring groups. Often these dramatic calls are accompanied by much branch-shaking and grimacing by the adult males (2).

Within each group a dominance hierarchy exists, but unlike many primate species, the dominance rank an individual attains is not related to its mother's rank, except in the first few years of life. Instead, young collared mangabeys rise to their own place in the dominance hierarchy by using a range of behaviours, most commonly by directly challenging a high-ranking monkey (7). Holding a high position within the dominance rank has benefits; generally, high-ranking males have more offspring than lower-ranking males (8).

The collared mangabey feeds primarily on fruits and nuts growing in its lush forest habitat, but supplements its diet with the stems and roots of plants in the undergrowth (2). These primates possess strong incisor teeth which enable them to also eat hard seeds, which the guenon monkeys, with which they share their habitat, can not (5).