Chimpanzees modify their food calls with respect to tree size for a high valued fruit species.

The vocalization capabilities of our closest living relatives, the great apes, often pale in comparison to their flexible gestural repertoire. However, the vast majority of literature on great ape communication, gestural and vocal, comes from studies conducted in captivity where the surrounding environment is vastly different from the socio-ecological context in which wild apes naturally communicate. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now investigated a specific call type, the chimpanzee food call, which has already been shown to be produced solely during a foraging context, and a study in captivity has also provided evidence for the call being functionally referential to conspecifics.