Spontaneous rhythmic and tool-assisted drumming across variable tempo and technique in a captive chimpanzee
Rhythmic drumming on percussive instruments is a common element of music across human cultures. Chimpanzees also drum on the buttress roots of trees and other resonant objects, and often combine their drumming with long-distance pant-hoot vocalizations. Previous studies have suggested that chimpanzees select drumming substrates for their acoustic properties and that chimpanzee drumming shares core elements of human musicality (e.g., non-random timing, isochronous - metronome-like rhythm, and de-contextualised production in captivity). But to what extent can chimpanzees flexibly control their drumming rhythm across percussive media and techniques? Here, we report on a long-lasting drumming event by a captive chimpanzee named Toon, which was performed across multiple pant-hoot displays and employed diverse action forms, including the use of multiple drumstick-on-drum multi-tools. We find flexible rhythmic production and isochrony across drumming implements, techniques, and tempos. Further, we describe tool set transport and reuse, selectivity of percussive acoustic properties associated with different vocal elements, and variable use of the facial expression "play face" associated with faster and less variable rhythms, potentially indicating intrinsic enjoyment of such rhythms. Together, these findings provide evidence for key elements of human musicality in Toons drumming, supporting the hypothesis of shared evolutionary roots of human and chimpanzee drumming.