Chimpanzees communicate with “stone-assisted drumming”

Europa Press

La Jornada Newspaper, Friday, June 6, 2025, p. 6

Madrid. Researchers have discovered a remarkable phenomenon among wild chimpanzees in West Africa: the use of stones to produce sounds, presumably as a form of communication.

During a five-year field study, behavioral biologists from Wageningen University and the German Primate Research Center collected video footage at five different locations within a nature reserve in Guinea-Bissau. This was made possible through the use of camera traps and the essential support of local field guides. In specific areas, a striking behavioral pattern was observed: adult male chimpanzees repeatedly banged stones against tree trunks, resulting in characteristic stone piles at the foot of the trees.

Sem van Loon, lead author of the study, published in the journal Biology Letters , refers to this behavior as stone-assisted drumming . It appears to be related to the classic hand- or foot-drumming on hollow buttress roots, which chimpanzees use to transmit information over long distances or to demonstrate dominance .

However, there are clear differences: before throwing stones, the animals tend to emit loud gasps, followed by silence, a pattern opposite to that of traditional drumming, where silence usually precedes the noise.

Cultural transmission

Van Loon suspects there's a different motivation for this behavior. These loud, low-frequency sounds may be intended to spread beyond normal intragroup communication , he suggests. The acoustic properties of a stone hitting a tree make this possible in densely wooded areas .

Observations point to cultural transmission. Young chimpanzees adopt the behavior of older members of the group, indicating that it is socially learned rather than genetically inherited.

Marc Naguib, professor of behavioral ecology, emphasizes the overall importance of the discovery: it illustrates that culture is not unique to humans and that these behaviors should also be considered in nature conservation .