Indirect rival assessment in a social primate, Theropithecus gelada

► We investigated gelada, Theropithecus gelada, bachelors' use of social information to assess rivals. ► Bachelors preferentially monitor male-male contests (over copulations) to assess rivals. ► Bachelors also maintain close proximity to units that have experienced a recent take-over. ► Bachelors thus appear to attend to cues of mating opportunities (e.g. elevated rates of fighting). ► Geladas appear to lack knowledge about third-party relationships between males and females.