Social network inheritance and differentiation in wild baboons

Immatures’ social development may be fundamental to understanding important biological processes, such as social information transmission through groups, that can vary with age and sex. Our aim was to determine how social networks change with age and differ between sexes in wild immature baboons, group-living primates that readily learn socially. Our results show that immature baboons inherited their mothers’ networks and differentiated from them as they aged, increasing their association with partners of similar age and the same sex. Males were less bonded to their matriline and became more peripheral with age compared to females. Our results may pave the way to further studies testing a new hypothetical framework: in female-philopatric societies, social information transmission may be constrained at the matrilineal level by age- and sex-driven social clustering.

Methods
We tested two hypotheses on how social networks change in immature (≤ 5 years old) wild chacma baboons (Papio ursinus), focusing on (1) the inheritance of maternal networks and (2) the shifts in network integration and social partner preferences. Social network (and other) data were collected between 2014 and 2019 by the Tsaobis Baboon Project (http://tsaobisbaboonproject.org/) on three baboon troops ranging across Tsaobis Nature Park (Namibia). We used social network analysis within a longitudinal framework to build proximity and grooming networks on immature individuals and their mothers. We ran linear and generalised mixed models using the software R 4.0.2.