West African chimpanzees drum in a different rhythm than their relatives from East Africa

Whoever sees a chimpanzee first rhythmically on a tree root and only then the characteristic pant-shout (panting In English) belongs, now knows: this is most likely a West African chimpanzee: Pan Troglodytus Verus. In East Africa, at Pan Troglodytus Schweinfurtiiit is the other way around.

This is apparent from a major inventory of the always striking drum behavior of chimpanzees. A large team of primatologists led by Vesta Eleetri (University of Vienna) and Catherine Hobaiter (University of St. Andrews, United Kingdom) has analyzed 371 observations, spread of six populations over the two subspecies. The biggest differences were found to exist within the two subspecies. For example, anyone who sees a chimpanzee on a tree root drums in changing rhythms, with shorter and longer intervals, know from now on: this is an even chimpanzee. The research report was published this week in Current Biology.

Chimpanzees mainly hit tree roots at rest moments while traveling through their residential area. It seems that they pass on to other members of their group where they are and also who they are, to find each other easier in the day. The well -known monkey researcher Christophe Boesch ever described How the Alpha-monkey Brutus in the West African Taï-Forest even seemed to pass on his travel direction to the other groups, by druming on two different trees, with the line between the trees indicating the new direction. And in His book About the chimpanzees of the East African Budongo forest, the British prima cow Vernon Reynolds noted that he and the other researchers were able to recognize the individual chimpanzees (often men, but sometimes also women) in their way of drums. They also had the impression that in Budongo the combination of drums with the panting-Ap a clear signal was that the drummer wanted to know where the others were. Incidentally, drums in the forest often sound further than calling. With chimpanzees, hitting on trees can also be part of a display of power.

Seek contact

The researchers of the rhythmic differences between East and West Africa emphasize in Current Biology The possibility that with this drum behavior a ‘precursor’ of the human musical abilities may have been found. The ability to drum would have already been present at the common ancestor of people and chimpanzees and bonobos, who probably lived somewhere around 8 million years ago.

The Dutch psychologist and primate researcher Mariska Crete (Leiden University) is happy with the new knowledge about the rhythmic communication with which chimpansegroepjes contact each other. As she says in an e-mail: « The pursuit of unity and connection with the group is something that chimpanzees share with people and many other social animals. »

But whether that ability to drum would really be present at the common ancestor of people and chimpanzee is by no means certain, she thinks. « Because, for example, the Bonobo, the monkey’s monkey that is just as far from us as the chimpanzee, drums much less and also very differently. Are they then lost? Probably not. They are very vocal and the vocalizations have meaning. »

According to Crete, it is more precisely to say that at most the capacity for rhythmic behavior, not drums, may have already been present at the latter common ancestor. « Chimpanzees seem to have retained or further developed this ability for dominance and displays, people for music and social coordination, while bonobos have developed it in a different direction. »

In a short response, music researcher Henkjan Honing (University of Amsterdam) in turn wonders how strong the connection with the evolution of music actually is. « It certainly doesn’t seem like a big breakthrough. Because this is not a beat perception, but Isochronie, the ability to move rhythmic, which has already been demonstrated in several monkey species. » As honey has often argued, the basis of the human music Not the ability to move rhythmically but the ability to take rhythms from others. And that has only been observed in animals, with the cockatoo Snowball as the best known. The other human music element is much rarer in the animal world. That is the ‘relative hearing’, the recognition of a melody independent of the pitch. Almost all animals have an absolute hearing, but partly because of that they do not recognize a melody if it starts in a different tone. For people that is a piece of cake.

To share

Mail the editors