In various behavioral contexts like fighting, eating, and playing, mammals produce distinct vocalisations. These vocal expressions may be evolutionary conserved, suggesting the possibility of shared acoustic features among closely related species. The new study by Kamiloglu, Sauter, Çalışkan, and Slocombe aims to explore this intriguing hypothesis.

The researchers compared the acoustic features of vocalisations produced by humans and chimpanzees in 10 similar behavioral contexts. Utilizing two complementary analysis methods—pairwise acoustic distance measures and acoustic separability metrics based on unsupervised learning algorithms—the team discovered something important: The vocalisations produced when threatening another individual were not only distinct from other types of vocalisations but also showed a high degree of similarity between the two species.

This cross-context analysis reveals that the acoustic features of threat vocalisations are likely part of a phylogenetically ancient vocal signaling system. In simpler terms, the way humans and chimpanzees vocally express threat could be a shared evolutionary trait, pointing to deeper, ancestral connections in how we communicate.

The findings offer a  glimpse into the evolutionary lineage of vocal communication and could have broader implications for our understanding of social and communicative behaviors across species.