Both aggressive and affiliative behaviour facilitate resource access in high-ranking female long-tailed macaques (Macaca fascicularis)

Access to limited resources may be achieved by dominance as well as by high rates of aggressive and affiliative behaviour. We investigated the relative effectiveness of dominance rank and aggressive and affiliative behaviour in accessing three material and three social resources. Aggressive and affiliative behaviour of 24 female long-tailed macaques was scored along with their success in resource access. Path models revealed that high-ranking individuals have more access to resources than low-ranking ones through their employment of both aggressive and affiliative behaviour. Physical aggression was effective in accessing two material resources (food and enrichment). Affiliative behaviour was effective in accessing one material (co-drinking) and one social (tolerance) resource. In conclusion, since aggressive behaviour was effective in accessing two material resources, while affiliative behaviour increased access to both a material and a social resource, affiliative behaviour is at least as important as aggressive behaviour for high-ranking individuals to access resources.