A study that documents tactical deception for the first time in primates living in a natural environment is reported this week in Nature Communications.
In wild gelada baboons, competition for mates is ever-present and has dramatic fitness consequences for the species. It has been suggested that individuals who ‘cheat’ on their mates in order to maximise their own reproductive success alter their behaviour to avoid detection yet there is very little evidence to support such deceptive behaviour. Using long-term observational data from a population of wild geladas in Ethiopia, Aliza Le Roux and colleagues assess this hypothesis. Gelada are known to produce copulation calls that are under voluntary control; Le Roux’s team found that certain males and females suppress copulation vocalisations while paying close attention to the position of the leader male, to try to cover up their infidelity. Although withholding information is considered a simpler form of deception than active falsification of signals, the authors suggest that this tailoring of vocalisations depending on the audience present implies that re productive concealment may be tactical.
In addition to increasing our understanding of the costs and benefits of different behavioural strategies, the presence of deception in geladas identified in this work allows us to further assess the cognitive underpinnings of their social behaviour and investigate other cognitive skills, such as higher order intentionality.