Testing the anxiety reduction function of grooming interactions in wild Barbary macaques (Macaca sylvanus)

Together with its hygienic and social function, grooming is thought to reduce anxiety. However, empirical evidence on the anxiety-reduction function of grooming is scarce. We collected 10-minute focal data on the donor and recipient of grooming using the post-grooming / matchedcontrol (PG-MC) method. In these PGs and MCs sessions, we recorded the occurrence of selfdirected behaviours (i.e. scratching and self-grooming), which are behavioural indicators of anxiety. We found mixed evidence of the relationship between anxiety and grooming interactions. The link between grooming and anxiety may be more complex than originally thought