An animal’s style of social relationships may affect their communication process. Many primates live in social groups with an unequal distribution of dominance. The distribution varies between primate species. A primate species’ dominance style ranges from democratic to despotic. In a despotic group, individuals assert their dominance over subordinates more than in a democratic group. Dominant individuals can choose whether to tolerate their subordinates. More tolerance is given in democratic groups. Subordinates can only be tolerated and cannot give tolerance. Previous researchers have studied groups from multiple primate species. They found that a species’ dominance style can affect the communication of an entire group. Specifically, more democratic groups had more vocal calls. However, researchers have not studied the effect of dominance and tolerance on individuals’ communication. The dominance style, whether despotic or democratic, may affect the individuals’ communication separately to the species. Communication could be different for every group member. Therefore, this study investigates whether dominance style alters communication at an individual and species level.
This study includes 111 groups from 26 species. There are two key findings. First, from observing group communication, the despotic species had more vocal calls associated with maintaining or forming the hierarchy than the democratic species. This means that the more despotic the species, the more hierarchy related calls the group produced. Second, for individuals, the amount of tolerance given by the dominant individuals affected communication. Dominant individuals vocalised more when they gave more tolerance to subordinates. However, subordinates’ rate of communication was not correlated with the tolerance they received. This indicates that a democratic group relies on dominant individuals to be more vocal than subordinates.
These results show that we should analyse animals’ communication as a species and as individuals. This is because communication changes for every individual within a group. At an individual level, subordinate individuals may be more pressured than dominant individuals to consider other group members, regardless of whether the dominant individuals tolerate them. Therefore, subordinates’ communication may not depend on dominance style. At a species level, future research should test whether dominance style remains stable across generations. By testing its stability, we may understand whether dominance style influences evolving communication styles. Overall, despotic groups were found to produce more hierarchy related vocal calls than democratic groups, but communication levels vary for each individual. Entry by Rebecca Cummins