The effect of dominance rank on behavioural response to playback calls in ring-tailed lemurs (Lemur catta)
In group-living species, dominance hierarchies play a central role in shaping social dynamics, influencing both agonistic and affiliative interactions. Being able to recognise an individual's dominance rank at a distance, can reduce direct conflicts, facilitating group coordination, and mediating social cohesion. While the role of dominance in relation to aggressive or reproductive vocalizations has been well documented, its influence on affiliative contact calls, particularly in mediating group movement and social integration, remains underexplored. We conducted playback experiments with free-ranging adult ringtailed lemurs (Lemur catta) at the Affenwald Wildlife Park to investigate how dominance rank of the caller and rank differences between caller and listener affect behavioral responses. Using Generalized Linear Mixed Models (GLMMs), we analysed three response variables: vocal response, number of visual scans, and occurrence of movement. Our results revealed sex-specific effects: females exhibited increased movement following contact calls from high-ranking individuals, and tended to refrain from moving when their own rank exceeded that of the caller. In contrast, no significant effects of dominance rank were observed in males. These findings suggest that high-ranking females may play an important role in initiating group movement. This study provides insights into the role of dominance rank in mediating social coordination through contact calls and provides a foundation for further research into the role of vocal communication in maintaining group cohesion in primates.