Food-associated calling sequences in bonobos

When encountering food, chimpanzees, Pan troglodytes, and some other primates produce specific calls, whose acoustic structure covaries with the caller's food preference. For chimpanzees, there is evidence that listeners use these contingencies to guide their own foraging behaviour. Here, we investigated the vocal behaviour of another great ape, the bonobo, Pan paniscus, in response to food. We were able to distinguish acoustically five different call types given during interactions with food. These calls were not given singly, but usually as part of long and complex call sequences. We established the food preference hierarchies for 10 different individuals, housed at two different facilities. We found that the composition of call sequences produced by these individuals was not random, but was related to the type of food encountered by the caller. Significant variation in call composition was explained by taking into account the caller's individual food preferences, suggesting that bonobo food-calling sequences convey meaningful information to other group members.