A visit to Budongo Conservation Field Station (September 2008)


Jean-Louis Dessalles

Telecom ParisTech



It has been a great privilege to be admitted into this sanctuary of wildlife scientific study (BCFS). I have been offered the possibility of approaching chimpanzees in the wild and of interacting with scientists who devote part of their lives to investigating the behaviour of this fascinating species. I consider that this visit will count as one of the most intense experiences of my own scientific life.


My research focuses on looking for fundamental principles underlying the language faculty and its biological origins. My activity involves an observational phase and a modelling phase. The former is, by inspiration, ethological: I try to observe human beings as they spontaneously behave in their normal habitat (i.e. not in the laboratory). For this reason, and also because I am mostly interesting in possible precursors of human language, I have always been fascinated by what ethologists have to say about the species closest to our own, namely apes. Among the books on apes that impressed me most, I must mention In the shadow of man (Jane Goodall, 1971), Gorillas in the mist (Dian Fossey, 1983), Chimpanzee politics (Frans de Waal 1982), The naked ape (Desmond Morris, 1967) and Kanzi: the ape at the brink of the human mind (Savage-Rumbaugh & Lewin, 1994). In my twenties, I read all Konrad Lorenz’s books and since that time I have always kept in touch with ethological literature.

Following Lorenz’s lesson, I consider ethology (= scientific study of spontaneous behaviour) as lying at the confluence between unprejudiced observation and theoretical thinking. Nothing systematic in behaviour is there by mere chance, but must bring some advantage to the performer. I read and savoured every word of The origin of species (Charles Darwin, 1859) and meditated the arguments put forward by Richard Dawkins, Edward Wilson and Stephen Gould in their milestone books. I was impressed by the way Game Theory can be applied to understanding animal behaviour, as shown by William Hamilton and John Maynard-Smith. Spontaneous behaviour has its rules, and they must be simple!

My concern, in the past decade, has been focused on signals. I became more and more convinced that human language, though differing in several qualitative ways form animal communication, is still a case of costly signalling. The biological motivation (in the Darwinian sense) of human communication is not the exchange of practical information. It is to display definite qualities. In this respect, we are unexpectedly close to many animal species, including apes (see below).

Having spent years in studying recorded spontaneous conversations in minute details, I was curious to see how scientists were dealing with spontaneous ape communication. In some respects, Chimpanzee communication is much better studied that human communication (we still lack quantitative data about language use!). I must say that I have been impressed by the methodology used by the BCFS scientists and by their constant demand for rigour, despite the countless difficulties associated with working in the field.

I must also concede that I expected much from my first contact with our sister species. Just observe them as they spontaneously behave and try to understand how the 0.003% difference in our evolutionary history can make such an impression on our minds. They are definitely not like us, and yet…

A great opportunity


I met Marion Laporte at the Evolution of Language Conference (Evolang) in Barcelona this year. I attended the lecture she gave there and I discovered how ignorant I was about the complexity of Chimpanzee signals. I also realized that young scientists were still there on the field, pursuing Jane Goodall’s adventure in the forest for the sake of science. Marion’s friendly and positive attitude gave the impression that everything was easy in this kind of enterprise. I knew it wasn’t, but at least I was speaking to one of these people who dare to do what I had been unable to do a couple of decades earlier, when I wondered whether I should go to Africa and study wild apes while there are still some around.


I met Marion again in Paris on March 19, before she left to fly back to Uganda. I had so many questions to ask about wild chimps. In the course of the conversation, she asked me why I did not come to see by myself. I needed a few seconds to understand she meant it seriously. I quickly and enthusiastically answered Ok, je viens!, before any cautious part in my mind be given a chance to object. The deal was done.

Marion has been incredibly helpful to make this visit easy. A few months after we met, I could see her standing in the forest, from just a two metre distance, a microphone in her hand, watching out for the slight vocalizations of a baby chimp. On my way back from Budongo, I begin to realize even more vividly how thankful I am to Marion, how lucky I have been to be offered this opportunity and how pleased I am now that I was able to take it.

Marion’s work was part of her PhD Thesis at the University of St-Andrews. Under the supervision of Klaus Zuberbühler, she is currently studying the ontogenetic emergence of chimpanzee vocal communication. Understanding how various signals develop in childhood may lead to a better understanding of their semantics and of their social significance. I remember that in her talk at Evolang, she showed how pant-grunts were emitted whenever an individual met a higher-ranking community member. It reminded me of the systematic salute I was required to perform when in the army. I had yet to discover that chimp society is much more complex that the military.



The Budongo Forest project

The Budongo forest is located in Uganda, close to Lake Albert, some 20 km from Masindi, 200 km north of Kampala.


The Budongo Conservation Field Station (BCFS) was founded in 1991 by Vernon Reynolds, who had already spent one year in that forest in 1962 studying chimpanzees. His fascinating book (Vernon Reynolds, 2005) tells the story of the Sonso community, a group of some fifty chimpanzees that we can observe as they live, as in a reality show. Before coming to the Budongo forest, I had of course read the book and become acquainted with Duane, Melissa, Nambi, Black and Vernon. I had to adapt as soon I arrived to the camp, as the prominent males (Duane, Vernon, Black) were all dead now and replaced at the top of the hierarchy by younger fellows named Nick and Bwoba.

Vernon Reynolds



The camp facility is a former sawmill. It is ideally located in the middle of the Budongo forest and offers unexpected comfort, including a hot shower (one day, the water was really hot!!). Chimps and other primates are continuously studied by a team of scientists. When I was there, Agnès was studying black-and-white colobus, whereas Cat, Kathie, Marion and Roman were studying chimps. They are helped by a team of a dozen field assistants. I met more particularly Tony, Monday, Geresomu and Sam. Some field assistants have pursued higher studies in Uganda. All of them have an invaluable knowledge of chimpanzee ecology. They know how to find chimps in the thickness of the forest, they know about their health and their state of mind, and they are able to anticipate some of their actions.


The Field station is managed by a Ugandan staff. I briefly met Dr. Fred Babweteera, the Project Director. I am thankful to him and to Prof. Klaus Zuberbühler, the Scientific Director, to have welcomed my visit to Budongo. The Budongo Forest Project gets funding from various sources (see the BCFS page), including funding from the Edinburgh Zoo and from the University of St-Andrews. All scientists who were active during my visit were from the University of St-Andrews.

The Budongo project is one of the very few places in which wild chimpanzees are closely observed. The knowledge we get from studying their live in detail is invaluable, as any opportunity to perform these studies may be lost in a foreseeable future. The Sonso community is one group of about 50 individuals, within a estimate population of 600 chimpanzees. These individuals have been habituated to human continuous presence. They tolerate close proximity to humans and most often seem to ignore them. It takes about three years or more to achieve such habituation. Human presence might not been without consequences though. After the death of several big males in the Sonso community, we may expect neighbouring communities to invade the poorly defended territory to take away their females. The presence of scientific observers probably prevents this from happening, as these non-habituated neighbours still fear humans.

What happened when I was there

Before my visit, it was not sure that I would witness anything noticeable happening among chimps. During the rainy season, chimps sometimes spend several days sitting quietly on top of tall trees chewing leaves. To my surprise and to my colleagues’ amusement, chimpanzee “welcomed” me on my first day at Budongo.


I heard pant-hoots while having breakfast. We went out and saw Nick, the alpha-male, slowly crossing the lawn between the buildings. I jumped to get my video-camera, soon enough to capture unforgettable moments. Five chimps had climbed on a straight tree just behind my own building. They were alternating loudly displays, chasing and reconciliation through grooming. The most memorable episode of that day was the arrival of Bwoba, welcomed from a distance by a chorus of impressive pant-hoots. He walked at a stately pace until he reached the tree and took his place as member of the party.




The following days were full of impressive encounters, even if we needed to make the first move to provoke them. Marion showed me how to observe the delicate gestures occurring between mother and infant.



The most impressive events to my naive eyes (or ears) are the bursts of pant-hoots, energetic signals that remain semantically opaque to me. On Friday morning, it first seemed that pant-hoots were merely uttered to signal one’s position in the forest (by the way they proved useful to us, as we were in trouble locating the chimps). Some individuals may remain impassive when others pant-hoot right behind their back, but at some other times some dominant individual may chase another one, lower in the hierarchy, while loudly pant-hooting. It seems that the chased individuals takes the thing seriously, though less than a moment later, chaser and chasee can be seen grooming each other for quite a while.

Discussions at Budongo

I was lucky enough to have highly rewarding discussions with the scientists at BCFS. I asked questions about their life in the forest, about the methodology used to study primates and about theoretical issues.

Concerning the latter, I was mostly concerned with the semantics of signals emitted by chimps.



It has been a great surprise to discover that signalling among chimps still requires semantic characterization and evolutionary explanations. I repeatedly questioned my colleagues about the function of pant-hoots. These signals are remarkable, because they are exaggerated. Individuals devote much energy in emitting these signals, often in chorus, as if competing to make them as loud as possible. Could it be that pant-hoots merely convey meanings as banal as “We’re here”, “We are happy”, “We are excited”?

Theories of competitive social signalling

According to available theories of competitive signalling, exaggerated signals results from competition among emitters (Zahavi & Zahavi 1997) and from the fact that receivers resist manipulation (Krebs & Dawkins 1984). Signals evolve until they become costly enough to be honest: they reveal the true “quality” of the performer, exactly as in sport competition. This is Zahavi’s handicap principle. Moreover, signals tend to evolve toward semantically poor and repetitive patterns, as in commercial advertisement, in conformity with Krebs and Dawkins’s prediction.

Part of my work has been to show that human language, though being semantically rich, non-repetitive and non-exaggerated, is still a case of competitive social signalling. Through language, human individuals advertise definite qualities (esp. being relevant) to be accepted in social networks. Can this model be transposed to aspects of chimpanzee signalling?

The basic question is: “What would a chimp lose if (s)he were to pant-hoot less loudly?” (or refrain from pant-hooting?)

One guess is that the social ‘existence’ of an individual depends on its ability to make its presence manifest on definite moments. But there are missing causal links in this statement. How can we characterize these ‘definite’ moments? Why are pant-hoots often emitted in chorus? Why are some pant-hooting episodes associated with aggression and others not? Why does social rank depend on pant-hooting performance? Can we predict aspects of the form of the signal? Why does pant-hooting go crescendo (as if to announce performance)? Who are the intended receivers of pant-hoots? I hope that these issues will be addressed and solved by specialists.

Snares and chimpanzee cognition

One of the puzzles I wanted to solve during my visit to Budongo was whether chimps had the ability to process topology. In my account of the evolution of language, the ability to make binary distinctions is what underlies negation and argumentation (Dessalles 2007). This ability is supposed to be what distinguishes homo sapiens from all other past or present species. It was thus crucial for me to see whether chimps had the ability or not.

My first question concerned the perception of territory borders. When asked about it, my colleagues unambiguously answered that chimps have a fuzzy perception of their territory. They know when they are approaching limits, which means great danger for males. But there is no idea of definite border.

Another indication of the fact that chimp do not process topology comes from their inability to free themselves from snares. Snares are a calamity. Everyday, a dozen snares are removed from the forest. There are used by the nearby population to catch small game. Half of the chimps in the forest get injured with snares during their lives, sometimes permanently (Reynolds 2005).

When chimps get caught in such a trap, they pull on the wire until getting badly hurt. Surprisingly, it does not occur to them that they could put a finger into the loop and pull to loosen it. This simple procedure is accessible to any human being, but it requires topological thinking. Apparently, the ability to process topology is one of the few qualitative differences between the two species.





Talk at Nyabyeya Forestry College

I was offered the opportunity to give a talk as part of BCFS Colloquium 2008, on Thursday 25:

Vocal “grooming” in humans
Why we talk and chimps don’t

The talk took place in the nearby Nyabyeya Forestry College. The audience was composed of the BCFS scientists and field assistants, together with local students. Being relevant to such a heterogeneous audience proved to be quite a challenge.

I got some really nice spontaneous feedback. I tend to believe that I was somewhat successful. If so, I am proud of it.



I presented my theory about the emergence of referential signals. Since the invention of lethal weapons by hominins, conventional primate politics (de Waal 1982) has radically changed. It became less important to have strong friends, but crucial to have informed friends that can prevent you from being taken by surprise. By signalling any unexpected event to whoever is here to listen, human beings show off the corresponding quality (Dessalles 2008). I was happy to observe that the theory made sense to scientists who are fully aware of the reality of chimpanzee politics.


This was my first journey to Africa (apart from one week in Morocco two years ago). It was a great culture shock. I encountered many friendly Ugandans. They seek for interaction, and it has been a pleasure to exchange views with them. The people I met are positively oriented and despite obvious problems, they are optimist for the future. In the regions I could visit (mainly Kampala and the region of Masindi, close to the Budongo forest), children go to school and learn English (on top of two local languages or more). They represent the promising future of that country.


Marion has initiated a project to encourage people of the nearby village to make baskets with raffia. Some 20 people, mainly women but not only, are now involved in the production. They show impressive creativity, as evidenced by the variety of basket shapes. I happened to be among the first buyers. Interestingly, some thinking was necessary to decide together with these new artisans what the right price could be, taking into account the costs (as raffia must be purchased), the time spent in the making and the aesthetic value of the objects.

Help chimps

There are various ways to help chimps and maybe prevent them from disappearing from Earth. You may adopt a chimp of the Budongo forest or support the BFCS. You may also donate to the Jane Goodall Institute.

Personal message

When deep in the forest, Marion showed me some leaves and asked me to smell them when crumpled. Now that I’m back and could check: I do confirm that they smell like “Pim’s à l’orange”.


As previously said, I am indebted to Klaus Zuberbühler and Fred Babweteera for welcoming my visit. This mission was funded by the CNRS. I am grateful to the decision-makers at Telecom ParisTech who proved especially broadminded on this occasion.


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