Social uncertainty promotes signal complexity during approaches in wild chimpanzees (Pan troglodytes verus) and mangabeys (Cercocebus atys atys)

Mathilde Grampp*, Liran Samuni, Cédric Girard-Buttoz, Julián León, Klaus Zuberbühler, Patrick Tkaczynski, Roman M. Wittig*, Catherine Crockford

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
3 Downloads (Pure)


The social complexity hypothesis for the evolution of communication posits that complex social environments require greater communication complexity for individuals to effectively manage their relationships. We examined how different socially uncertain contexts, reflecting an increased level of social complexity, relate to variation in signalling within and between two species, which display varying levels of fission–fusion dynamics (sympatric-living chimpanzees and sooty mangabeys, Taï National Park, Ivory Coast). Combined signalling may improve message efficacy, notably when involving different perception channels, thus may increase in moments of high social uncertainty. We examined the probability of individuals to emit no signal, single or multisensory or combined (complex) signals, during social approaches which resulted in non-agonistic outcomes. In both species, individuals were more likely to use more combined and multisensory signals in post-conflict approaches with an opponent than in other contexts. The clearest impact of social uncertainty on signalling complexity was observed during chimpanzee fusions, where the likelihood of using complex signals tripled relative to other contexts. Overall, chimpanzees used more multisensory signals than mangabeys. Social uncertainty may shape detected species differences in variation in signalling complexity, thereby supporting the hypothesis that social complexity, particularly associated with high fission–fusion dynamics, promotes signalling complexity.
Original languageEnglish
Article number231073
JournalRoyal Society Open Science
Issue number11
Publication statusPublished - 29 Nov 2023


  • Social complexity
  • Signal combination
  • Multisensory signalling
  • Behavioural flexibility
  • Fission–fusion dynamics


Dive into the research topics of 'Social uncertainty promotes signal complexity during approaches in wild chimpanzees (Pan troglodytes verus) and mangabeys (Cercocebus atys atys)'. Together they form a unique fingerprint.

Cite this