Preliminary study of intra- and inter-group behavioural synchronization in owl monkeys (Aotus azarae) in the Argentine Chaco.

Maintaining behavioural synchronization is crucial in primate groups to preserve cohesion among individuals. For primates with a monogamous mating system and pair-living social organization, maintaining strong bonds and cooperation is essential. The aim of this preliminary study was to explore behavioural synchronization in owl monkeys (Aotus azarae). We simultaneously observed five groups in the Argentinean Chaco to evaluate within-group synchronization between adult male-female pair mates, between-group synchronization among males and among females, and the spatial dynamics of neighbouring groups. Pair mates showed a high degree of activity synchrony, often performing the same activity at the same time, with resting being the most synchronized behaviour. However, at the inter-group level, only resting showed a high degree of synchronization. All groups were active in the morning, began their first resting period at approximately the same time, and finished their activities at similar times, evidence of temporal synchronization. Neighbouring groups moved apart more often than they approached each other, particularly in the afternoon, suggesting active avoidance and potentially explaining the lack of inter-group encounters observed. These preliminary results provide insights into the social behaviour of the species and the cohesion they maintain. Further analyses are needed to better understand the mechanisms underlying cohesive behaviour and how it shapes group synchronization in Aotus azarae.