Coordination in Primate Mixed-Species Groups

Abstract

Groups formed by individuals from different species (mixed-species groups) are a widespread phenomenon amongst primates. Although the formation and maintenance of such mixed-species groups may incur costs to participating individuals, they render a net benefit, mainly through increased safety from predators and increased foraging efficiency. In contrast to the large number of studies that have examined the benefits and costs of primate mixed-species groups, there are still very few studies that have analysed the mechanisms of group coordination in mixed-species groups. Available evidence suggests that this coordination is mainly through vocal communication, but since the same vocalisations may be employed in intra-specific within-group and between-group communication as well as in inter-specific communication, it is difficult to analytically separate intra- and inter-specific coordination. The need for inter-specific coordination is likely to be highest when asymmetries in benefits from a mixed-species troop’s formation are strong. Thus, “goal-dependent management of interdependencies” is necessary to maintain the integrity of mixed-species groups.