Testing the Cognition of the Forgotten Colobines: A First Look at Golden Snub-Nosed Monkeys (Rhinopithecus roxellana)

Although our understanding of primate cognition is growing rapidly, little is known about the cognition of colobines. Here we report the results of a set of 5 experiments on colobine cognition using 17 golden snub-nosed monkeys (Rhinopithecus roxellana). These monkeys are folivores that form multilevel societies with groups of hundreds of individuals and relatively high fission-fusion dynamics. We investigated their sensitivity to human social cues and ability to inhibit impulsive behavioral responses. In three sociocognitive experiments we found that, like most other primates, they follow the gaze direction of a human demonstrator but there is no evidence that they use others' social cues in a cooperative task to locate hidden food or in a competitive task to steal forbidden food. In two inhibitory control experiments, we found that the monkeys showed a low level of inhibitory control, comparable to that of other folivorous primates. These results suggest that phylogeny and folivory might have been important in shaping the cognition of golden snub-nosed monkeys. Moreover, this species' large group size and relatively high fission-fusion dynamics may not have imposed a significant social challenge to their cognition, as social interactions occur mainly within basic social units.