Display of Aggression in Chimpanzees

In both transitive and intransitive dominance structures, dominance is established, communicated and maintained through specific behaviors. In chimpanzees, these behaviors and their functions can be easily observed and clearly identified. Such behaviors include repetitive rocking, a piloerection, bipedalism, charging, stamping, branching, throwing objects, and a behavior called a ‘hunch over’, where the displaying chimpanzee straddles a subordinate chimpanzee with its arms (Coe and Levin 2006). The function of each behavior varies; bipedalism and piloerection make the displaying chimpanzee look physically larger (and therefore stronger). Branching, charging, and stamping directly indicate strength. A ‘hunch over’ display emphasizes the social influence of the displaying chimpanzee (Coe and Levin 2006). The frequency of these behaviors and their effectiveness at conveying dominance vary from individual to individual. Although these specific behaviors and postures are always present, adult chimpanzees use different approaches to develop and progress their status in the dominance hierarchy (Anestis 2005)."

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