Social dynamics of vervet monkeys are dependent upon group identity.

Abstract

Traditions are widespread across the animal realm. Here, we investigated inter-group variability of social dynamics in wild vervet monkeys (Chlorocebus pygerythrus). We analysed 84 704 social behavioural interactions involving 247 individuals collected over nine years in three neighbouring groups of wild vervet monkeys. We found that, in one group - Ankhase - individuals had a higher propensity to be affiliative (i.e., sociality) and grooming interactions were more reciprocal. Despite yearly fluctuations in sociality, differences between groups remained stable over time. Moreover, our statistical model predictions confirmed that these findings were maintained for similar sex ratios, age distributions and group sizes. Strikingly, our results suggested that dispersing males adapted their sociality to the sociality of the group they integrated with. As a whole, our study sheds light on the existence of stable social dynamics dependent upon group identity in wild vervet monkeys and suggests that at least part of this variability is socially mediated. Graphical Abstract HighlightsO_LIThe sociality of vervet monkeys groups differs consistently across a nine years study despite similar genetic and ecological environments. C_LIO_LIDispersing males adapt their sociality according to the group they integrate with. C_LIO_LIIn the most social group, grooming interactions were more reciprocal. C_LI