We have been accumulating data on a population of geladas in the Simien Mountains National Park (SMNP) of Ethiopia. Geladas have several remarkable features that make them ideal for this research. First, geladas live in extremely large groups, where it is unlikely that individuals “know” (i.e. recognize) all other group members. This stands in sharp contrast to the typical small, stable primate group in which individuals recognize every other group member and repeatedly interact with the same individuals. As a result, most primates – but perhaps not geladas – have a wealth of social knowledge on the individuals around them and can use previous interactions to assess individuals and modify responses. To test this hypothesis, we have documented the limits of individual recognition using playback experiments. In fact, males actually have very little recognition of other males in their band – even males they encounter nearly every day (Bergman, 2010).

Second, in gelada society males may benefit from eavesdropping on the relationships among other males and females – mainly because female choice plays an important role in the outcome of male-male competition. We propose that males who selectively challenge rivals with weak attachments to their females should have more success at acquiring those females. To test this hypothesis, we used playback experiments to determine whether a subject male knows which males and females are associated using playback experiments. Such knowledge is necessary (but not sufficient) if males are monitoring the quality of the relationship between males and females. In a subsequent step, we are examining whether males that have weak relationships with females are selectively targeted by rival males.

Social Cognition

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