In a groundbreaking analysis of spontaneous performances by a male chimpanzee named Ayumu, researchers discovered that the chimp’s rhythmic prowess and expressive “playful face” provide insights into how early humans might have transformed vocal emotions into musical instrument sounds.
Chimpanzee Ayumu exhibited long, multi-element musical displays by drumming and manipulating objects. The analysis of his rhythmic transitions revealed structured sequences, primarily isochronous timing, and a more stable tempo with tools compared to body drumming. His playful expressions suggest heightened arousal and positive emotions, reinforcing the concept that emotional vocal expressions can manifest through instrumental sounds. Image provided by: Hattori et al., doi: 10.1111/nyas.70239.
In February 2023, Ayumu, a 26-year-old male chimpanzee at the Center for Research on the Origins of Human Behavior and Evolution at Kyoto University, showcased a spontaneous musical performance that intrigued researchers.
He creatively removed floorboards to use as drums, generating complex sounds reminiscent of vocal expressions.
Dr. Yuko Hattori of Kyoto University noted, “Ayumu’s drumming is not unprecedented.” Chimpanzees are indeed recognized for their musical talents, especially in drumming.
However, Dr. Hattori emphasized that Ayumu’s unique combination of drumming and vocalizations introduced multiple rhythmic elements, marking a novel instance.
Between February 2023 and March 2025, researchers documented a total of 89 spontaneous performances by Ayumu.
The recordings reveal him ripping floorboards apart to create music through innovative tool use.
“Observing chimpanzees utilize tools to produce diverse sounds and express vocal emotions was fascinating,” remarked Dr. Hattori.
The researchers aimed to determine if vocal expressions could transition to instrumental sounds based on Ayumu’s performances.
They meticulously categorized his actions into elements such as hitting, dragging, and throwing.
Transition analysis was utilized to differentiate between random occurrences and intentional actions.
Finally, they assessed the rhythmic stability of tool use versus hand and foot drumming by analyzing intervals between strikes.
Notably, they found that the order of sounds produced was structured, with isochronous intervals that maintained a constant tempo, akin to a metronome.
Indeed, using tools yielded a more consistent rhythm compared to solely relying on hands and feet.
The researchers also documented Ayumu’s facial expressions, including the “play face,” commonly associated with playfulness and positive emotions.
This type of emotional signaling, typically absent in audio displays, suggests that vocal emotions may have previously been externalized into sounds produced with tools.
“Ayumu’s performance illustrates that non-human primates have the capacity to externalize voice-like expressions through musical instruments,” the authors concluded.
Moving forward, they expressed interest in studying the reactions of other chimpanzees and the influence of Ayumu’s performance within his social group.
For detailed insights, refer to the study published in Annual Report of the New York Academy of Sciences.
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Yuko Hattori et al., 2026. Combination of Instrument Sound Production in Captive Chimpanzees: Evolution of Vocal Externalization. Annual Report of the New York Academy of Sciences 1557 (1): e70239; doi: 10.1111/nyas.70239
Source: www.sci.news
