Nimba Mountains,
Seringbara Region, Guinea

Nicolas Buzzi, Composer/Performer, Zurich/Frankfurt
Kathelijne Koops,
Primatologist/evolutionary Anthropologist, University of Zurich

On the border between Guinea, Liberia, and the Ivory Coast, the Nimba Mountains rise green and gentle. Their slopes are covered with dense forests and lush grasslands. The area is abundant in vegetation and water – Nimba is one of the most biodiverse areas in West Africa.

Here, for two decades, primatologist and evolutionary anthropologist Kathelijne Koops has been studying the behaviour of wild chimpanzees (Pan troglodytes verus). Her field team uses a range of innovative methods, including camera traps, to study how and why apes develop their cultural skills.

Their research raises fundamental questions: How did we humans become the cultural beings we are today? What connects our culture to the cultures of other great apes? What is the relationship between nature and culture? And what, ultimately, distinguishes human beings from non-human animals?

Swiss artist and performer Nicolas Buzzi takes up these questions and continues them with artistic means. Their music installation Who’s calling can you hear is based on the data Kathelijne Koops’ camera traps have recorded over the years in Nimba. It offers its visitors a symmetrical perspective that understands humans, non-human animals, and their environment as a unity, takes cultural diversity and modes of expression seriously across species, focuses on interactions between ecology and culture, and in this way conveys central concerns of nature and species conservation.

Chimps drumming in Nimba (2022).

Chimpanzees live in so-called fission-fusion societies. That is, they live in larger communities of about fifty animals, which however often split up into smaller sub-groups (fission) and merge again with other sub-groups (fusion). During the day, the chimpanzees forage alone or in small sub-groups. To communicate with each other in the dense forest, they drum on trees and use long-distance calls.

These sounds are important for Kathelijne Koops’ research. Whenever she and her team are tracking chimpanzees in Nimba, they listen very carefully to the sounds of the forest. The terrain is steep and many areas through which the chimpanzees move effortlessly are almost or completely inaccessible to humans. By listening to the calls and drums of the chimpanzees, Kathelijne finds out where they are. Only rarely does she actually see them – the chimpanzees are shy and avoid humans.

Because the chimpanzees are wary of humans, Kathelijne Koops uses indirect evidence of behaviour (like abandoned tools), along with camera traps to observe and study their behavior. This allows her to document the great cultural diversity of the chimpanzee communities of Nimba. Just like humans, chimpanzees have cultures that differ from community to community (→Koops, 2020) and that they pass on through generations (→Koops et al., 2022).

Over the years, these camera traps have repeatedly documented chimpanzees drumming on tree buttresses using both hands and feet (→Fitzgerald, Koops et al., 2022). Presumably, this so-called buttress drumming is a form of long distance-communication. There is even evidence that the chimps develop their own styles and rhythms while drumming (→Eleuteri, Hobaiter et al., 2022). These acoustic artifacts are the focus of Nicolas Buzzi’s installation Who’s calling can you hear.

Nicolas Buzzi recording (2023).

In a darkened room, excerpts of the camera trap videos showing the monkeys drumming and singing are projected by a projector onto a screen. The soundtrack, however, is replaced by a transcribed and electronically instrumented version, based on the figures and patterns created by the calls and drumming, and the chimp’s surroundings as well.

The instrumentations are not left untouched; the sometimes-wild mixtures of shouting and drumming become human/metric quantized musical cues that take on a life of their own and evolve detached from the chimpanzees. Through this transcription, the acoustic artifacts of the animals are translated and humanized, emphasizing shouting and drumming and waiting for responses as communicative acts. 

Next to the drumming and calling, other scenes captured by Kathelijne Koops’ camera traps in the Nimba Mountains are shown: Chimpanzees foraging, eating, moving alone or in groups, scouting the environment, or grooming themselves. Companion species of chimpanzees also appear, or simply the forest, their habitat. Partially transformed edits of these recordings, representing ambient sounds such as rustling trees and the calls of other species, accompany, complement and complete the music. 

After an understanding of the forest as well as of the musical form is established, the projection changes, at points starting to fade. With this symbolisation of the elimination of species in ecosystems through human actions, the music also transforms, as it thins out. More and more frequency bands are omitted and gradually register after register is filtered out. As the projection dissolves into rain, all bands fade out eventually.

With its artistic character, Who’s calling can you hear opens up an immediate access to scientific nature and species conservation. With this partly intuitive approach, the installation breaks down dichotomous thought patterns and categories. It leads its visitors to question seemingly fundamental opposites – nature versus culture, humans versus animals, scientific versus artistic knowledge – and thus to develop a systemic perspective that is essential to effective conservation efforts.

This way, Who’s calling can you hear broadens and interrogates perspectives on human and non-human cultures. If other apes also develop complex cultural expressions – what, then, makes us human?

Furthermore, the installation raises awareness for the disappearance of habitats in the Anthropocene. Due to palm oil and coffee plantations, deforestation and the extraction of mineral resources, ever larger areas of the natural habitat of chimpanzees are being lost. In the Nimba Mountains, they are also threatened. Although the region was declared a UNESCO World Heritage Site in the early 1980s because of its high biodiversity, it is threatened by mining, poaching, and deforestation. It has been on the →Red List of World Heritage in Danger since 1992.

This is the urgent message behind Who’s calling can you hear: We must act now to protect Nimba chimpanzee communities and to preserve their cultural diversity in the wild (→Kühl et al., 2019; →Koops, 2020; →White, 2021).

Swiss composer/performer and sound artist Nicolas Buzzi, born in Bern in 1987, lives and works in Zurich and Frankfurt. Their practice focuses on perception, environment, and cultural quantities to interrogate perspectives on socially relevant issues, moving across diverse fields of music, film, visual and performing arts. Buzzi directs the Electronic Studio at the Frankfurt University of Music and Performing Arts. Their work is being or has been shown at the Venice Architecture Biennale, HKW Berlin, Istituto Svizzero Milano, NUP Tallinn, Kunstmuseum Basel, NAC Lithuania, São Paulo Architecture Biennale, Schauspielhaus Zurich, Bern Music Festival, Taylor Macklin Zurich, Theater Basel, and ZKM Karlsruhe.

Evolutionary anthropologist and primatologist Prof. Kathelijne Koops has served for two decades as co-director of the Nimba Chimpanzee Project in the Nimba Mountains, Guinea (West Africa), where she studies the behavior and material culture of great apes. In 2011, she completed her Ph.D. at Cambridge and has been teaching in Zurich since 2014. Since 2021, she is SNF-Eccellenza Professor at the Institute of Anthropology, University of Zurich, and head of the Ape Behaviour and Ecology (APE) Group. She currently leads the SNSF-funded Comparative Human and Ape Technology (CHAT) project, which investigates the influence of ecological, social, and cognitive factors on the development and evolution of tool use in chimpanzees, gorillas, bonobos, and humans. Through her research, she hopes to identify processes that drive technology use in different ape species, answering the question: What makes us human?