The communicative function of self-directed behaviours in macaques

• Main Author: Whitehouse, Jamie
• Other Authors: Waller, Bridget Marguerite ; Micheletta, Jerome Francois ; Kaminski, Juliane
• Published: University of Portsmouth 2018
• Subjects: 150
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.765707

humans and non-human animals, stress is often linked to observable behaviours (e.g scratching, self-grooming and other self-directed behaviour). The link between stress and these behaviours is widely accepted, but their adaptive value remains understudied and so, the reasons for their production is unclear. Stress behaviours are often highly visual (e.g. scratching, yawning, self-grooming), and so it has been hypothesised that these behaviours may provide information to others. In this thesis I explored the hypothesis that stress behaviours (e.g. scratching) have communicative function, using a non-human primate model genus, the macaques (Macaca). First, I consider how observers perceive the scratching of others, and more specifically, how they are perceived in comparison to neutral, non-communicative behaviour. Macaques attended to the scratching of others more so than neutral behaviours, with this shift in attention being modulated by the degree to which the subject is bonded with the actor. Second, I measured how the macaques responded to the stress of others, comparing social interactions with and without a preceding scratch. The findings of this study demonstrate that producing stress behaviour significantly impacted the likelihood of aggression from others, and led to more peaceful social interactions. Finally, I considered the function of scratching during two other contexts, preceding behavioural change, and as a signal during grooming interactions, however, I found no evidence for a communicative function of scratching in either of these contexts. Overall, this thesis supports the idea that stress behaviour is perceived and responded to by others, providing some of the first evidence to suggest that these behaviours may function communicatively. Ultimately, these data adds clarity as to why stress behaviours have evolved, and why they exist in the behaviour repertoire of many social animals (including ourselves).