In the jungle cacophony, a scientific study manages to establish that « the chimpanzees drumm in rhythm » – Liberation

Musicality is not limited to man. This is the track that a study published this Friday in Current Biology,, Who establishes that like humans, chimpanzees are capable of drumming in rhythm. Better still, two subspecies of these primates of the East and West Africa have a proper way of doing so, still according to this study.

« Finally, we were able to measure that the chimpanzees are drumming in rhythm, and not only randomly, », Explained to AFP Vesta Eleuteri, of the University of Vienna, main author of the study, which adds credit to the theory that elements of musicality existed before the separation between the human species and the chimpanzees, 6 million years ago.

Previous scientific studies have shown that chimpanzees hit the roots of the trees with your foot, Creating sounds that allow them to communicate over long distances. The idea that the drumming of trees by these monkeys could help understand the origins of musicality in the human species has long fascinated researchers. But it had so far been difficult to collect sufficient data usable in the jungle cacophony.

For this new study, Vesta Eleuteri and her colleagues, including Catherine Hobaiter, from the University of St Andrews in Scotland, and Andrea Ravignani, from Sapienza University in Rome, compiled more than a century of data based on observation. After having managed to rule out parasitic sounds, the team focused on 371 good quality percussion samples, recorded with 11 chimpanzee communities from six groups living in the wet forest or the savannah in East and West Africa.

Their analysis shows that chimpanzees drums with an assertive rhythmic intention, that the frequency of their beats is in no way random. Distinctions also appear between subspecies: chimpanzees living in West Africa tend to produce more regular intervals, while those in the east more frequently alternate long and short intervals. To the west, they also drumm more often, retain a higher tempo and use drumming earlier during their vocalizations.

The researchers have not yet been able to determine what explained these differences, but suggest that they could indicate differences in social dynamics. The faster and faster rhythm of the western chimpanzees could testify to greater social cohesion, according to the authors, who note that they are often less aggressive towards individuals outside the group. In contrast, the more irregular rhythm of the East chimpanzees would be associated with more nuances, useful for locating companions in a more dispersed habitat.

Now, Catherine Hobaiter would like to continue studying this data to determine if there are intergenerational variations between rhythms within the same group. « Music is not only a difference between various musical styles, but a musical style like rock or jazz will itself evolve over time », she said. « We will have to find a way to distinguish group differences and intergenerational differences to achieve this question of whether it is learned socially or not »she explains. « Do you have an individual who arrives with a new style and the next generation resumes it ? «