About This Project

Individually distinct vocalizations allow animals to respond differently based on caller identity, sex, and group membership. Western gorillas live in densely forested habitats and vocalize often. However, no experiments have been conducted yet to explore the cognitive processes underlying their vocal communication. Do they recognize individuals from their calls alone? Are some calls easier to recognize than others? And if so, what might be the evolutionary explanation?

Ask the Scientists

What is the context of this research?

During my PhD I discovered that western gorillas use at least 17 call types, some at close distance and others when spatially separated, and that their calls are individually distinct, similar to human voices. This just lead to more questions: Are gorillas able to recognize individuals by vocal cues alone? If so, is this ability influenced by call structure, or the spatial or social context in which they are used? Western gorillas are the ideal species to look at these questions since they vocalize often, at both long and short distance, and live in an environment with limited visibility where vocal communication play a very important role.

What is the significance of this project?

Understanding the vocal recognition ability of gorillas has several important implications. First of all, it will help us to test major theories proposed so far on the evolution of vocal recognition. Second, it would be an important first step on the road to understanding the social cognitive abilities of the least studied African ape, and thereby filling a major gap in our knowledge of primate communication. This information is critically important for reconstructing the evolution of primate and ape evolution of vocal communication and for refining models for the origin and evolution of human language.

What are the goals of the project?

In order to test whether western gorillas recognize the calls of conspecifics, we will conduct a series of playback experiments at the Atlanta Zoo. First we will test whether they are able to distinguish between calls from familiar versus unfamiliar conspecifics, and secondly, we will test whether they recognize some calls more easily than others. For the first experiment we will play a call of a known gorilla and one of a gorilla they never met. In the second experiment we will play calls from the same known individual from an expected and an improbable location, and we will repeat the experiment using different call types. If their responses differ, it will indicate that they are able to discriminate individuals based on vocal cues alone.