| Abstract: Muzzle contact, where one animal brings its muzzle into close proximity of another, has often been hypothesized as a rather straight-forward means of socially-mediated food investigation. However, such a function has never been clearly demonstrated. Using 2,707 observations of muzzle contact occurring across three troops of wild vervet monkey (Chlorocebus pygerythrus), we tested this social learning hypothesis. While we found that muzzle contact can afford social learning, muzzle contact does not appear to be a behavior phylogenetically selected for a specialized social learning function, but rather a behavior mediated by operant learning which can then afford social learning. Rather than target specific individuals in order to gain information, we show that some animals serve as discriminative stimuli for approach for others, and that foraging animals serve as discriminative stimuli for food availability. We believe that animals engage in muzzle contact as a low-cost means of maintaining a baseline rate of information about their environment. We discuss these findings in light of the social learning literature, and highlight the need for similar analyses of behavioral function in the discussion of the evolution of social learning. |