Chimpanzees are genetically close to humans and share many emotional, behavioural and social similarities. One area that has recently come to light is the ability to make music. Not only is this trait apparent across groups, it is also evident that different groups of chimpanzees favour different beats.
The research finds that chimpanzees drum rhythmically, using regular spacing between drum hits. Their results show that eastern (Pan troglodytes schweinfurthii) and western (P.t. verus) chimpanzees — two distinct subspecies — drum with distinguishable rhythms.
The researchers suggest that the chimps use these percussive patterns to send information over both long and short distances. This is clearly non-random timing, which means that musical rhythm consists of events (hits) structured in time rather than produced randomly.
The scientists also say these findings suggest that the building blocks of human musicality arose in a common ancestor of chimpanzees and humans.
According to lead researcher Vesta Eleuteri of the University of Vienna, Austria: “Based on our previous work, we expected that western chimpanzees would use more hits and drum more quickly than eastern chimpanzees.”
Earlier studies showed that chimpanzees produce low-frequency sounds by drumming on buttress roots — large, wide roots that grow above the soil.
Yet a surprise was in store, as Eleuteri continues: “But we didn’t expect to see such clear differences in rhythm or to find that their drumming rhythms shared such clear similarities with human music… What we didn’t know was whether chimpanzees living in different groups have different drumming styles and whether their drumming is rhythmic, like in human music.”
By studying 371 drumming bouts in 11 chimpanzee communities, including six populations and two subspecies, the researchers found that chimpanzees drum with rhythm and that the timing of their hits is non-random and often evenly spaced.
Eastern and western subspecies also exhibited different drumming patterns; western chimpanzees used evenly spaced hits while eastern chimpanzees more often alternated between hits at shorter and longer time intervals.
It was additionally found that western chimpanzees hit their “drums” more, using a faster tempo, and integrated their drumming earlier in their pant-hoot vocalizations.
By showing that chimpanzees share some of the fundamental properties of human musical rhythm in their drumming is a step in understanding when and how humans evolved this skill. The findings suggest that this human ability to drum rhythmically may have existed long before we were human.
The research appears in the journal Current Biology, titled “Chimpanzee drumming shows rhythmicity and subspecies variation.”
