In a groundbreaking study emerging from Kyoto University’s Center for the Evolutionary Origins of Human Behavior (EHUB), a remarkable discovery has been made that may rewrite our understanding of the origins of musicality in primates. In February 2023, Ayumu, a 26-year-old male chimpanzee housed at the center, performed an unprecedented musical display that combined both instrumental sound-making and vocalizations. This unique behavior involved Ayumu removing floorboards from a walkway and using them as percussive tools while simultaneously producing complex and structured vocal sounds. This spontaneous fusion of rhythm and voice represents a novel insight into the cognitive and communicative capabilities of our closest living relatives.
While it is well-documented that chimpanzees are adept at instrumental behaviors like drumming, Ayumu’s performance went beyond mere rhythmic action. The intricate combination of tool-mediated percussion with vocal expression suggests a potentially fundamental evolutionary link between instrumental sound production and vocal communication. By examining over 89 isolated performances recorded between 2023 and 2025, researchers gained an unprecedented window into the mechanics of Ayumu’s musical creativity, including how he manipulated his environment to produce varied sounds and the emotional context accompanying these displays.
The methodological approach of the research team involved meticulous video analysis to deconstruct Ayumu’s behavior into constituent elements such as striking, dragging, and throwing. These discrete actions were then subjected to transition analysis, a statistical technique that assesses the likelihood of sequential behaviors occurring due to chance versus intentionality. The researchers identified patterns that strongly indicated deliberateness in Ayumu’s sequence of movements, pointing to an advanced cognitive capacity for combinatorial sound production that integrates multiple motor skills and rhythmic timing.
A particularly fascinating aspect of the findings is the rhythmic regularity observed in the sequences of percussive sounds. The intervals between tool strikes demonstrated isochrony, meaning Ayumu maintained a remarkably steady tempo over extended periods. This temporal precision resembles the consistent beats maintained by human metronomes or professional percussionists. Interestingly, the use of detached floorboards as striking implements yielded more rhythmically stable patterns than drumming performed with hands or feet alone. This stability hints at an enhanced control over sound production when external objects are employed as musical instruments.
Emotional expression accompanied these rhythmic performances, with Ayumu exhibiting what researchers term the “play face” — a facial expression associated with positive emotional states during playful activities. The presence of this affective display during instrumental sound-making is significant because such emotional cues are typically documented during vocal displays but rarely observed accompanying tool use. This observation suggests a potential evolutionary trajectory where vocal expressions of emotion become externalized and amplified through instrumental sound production.
The broader implications of this research extend to longstanding hypotheses concerning the evolution of music and emotional communication. Prior studies have posited that prehistoric music may have originated through the externalization of internal vocal emotions via physical tools and instruments. However, archaeological evidence has been difficult to obtain, especially for ancient percussion instruments fashioned from perishable materials like wood and animal skins. Ayumu’s behavior offers a tangible, empirical model to track how instrumental music could emerge naturally in non-human primates, lending support to theories that music’s origins lie intertwined with both vocal and manual expressions.
Moreover, by demonstrating the capability of a non-human primate to intentionally combine vocalizations with tool-assisted rhythms, the study provides insight into the neurological and cognitive architecture underlying musicality. The findings suggest that the shared ancestor of humans and chimpanzees may have possessed foundational traits enabling complex sound production beyond mere communication—traits that could have been built upon during human evolution to create the rich musical cultures we see today.
The upcoming research initiatives at EHUB aim to investigate the social responses of Ayumu’s group members to his musical displays. Understanding if and how other chimpanzees react to or participate in his drumming could unveil the social functions of musicality in non-human species, whether for bonding, territorial display, or emotional synchrony. Such data would enrich the evolutionary narrative by situating music within the broader context of primate social systems.
Ayumu’s performances stand not only as a testament to the cognitive sophistication of chimpanzees but also challenge anthropocentric views of art and culture. The ability to externalize vocal expressions through tool use may represent an ancient bridge linking communication, emotion, and creativity across species. This research opens exciting new avenues for interdisciplinary examination, combining primatology, neuroscience, archaeology, and musicology.
In conclusion, the study titled “Combinatorial Instrumental Sound-Making in a Captive Chimpanzee: Evolution of Vocal Externalization,” published in the Annals of the New York Academy of Sciences on March 25, 2026, reveals that instrumental music is not a strictly human domain. Through deliberate tool use coupled with vocal expressions, Ayumu exemplifies the evolutionary continuity of musicality, providing a living model of how rhythm and sound-making could have originated among early hominins. The precision, intention, and emotional content uncovered in Ayumu’s drumming will undoubtedly inspire future research into the evolutionary roots of music and the shared cognitive heritage of humans and chimpanzees.
Subject of Research: Animals
Article Title: Combinatorial Instrumental Sound-Making in a Captive Chimpanzee: Evolution of Vocal Externalization
News Publication Date: March 25, 2026
Web References: https://doi.org/10.1111/nyas.70239
Image Credits: Yuko Hattori
Keywords: Primates, Nonhuman primates, Tools, Music, Evolution
