Prof. Dr. Christophe Boesch
Prof. Dr. Christophe Boesch
Phone:+49 341 3550-200/201Fax:+49 341 3550-119

Max-Planck-Institute for Evolutionary Anthropology, Leipzig

Website Christophe Boesch

Dr. Tobias Deschner
Dr. Tobias Deschner
Phone:+49 341 3550-207

Max-Planck-Institute for Evolutionary Anthropology, Leipzig

Website Tobias Deschner

Dr. Roman Wittig
Dr. Roman Wittig
Phone:+49 341 3550-204

Max-Planck-Institute for Evolutionary Anthropology, Leipzig

Website Roman Wittig

Chimpanzees in West Africa

The Max-Planck-Camp at Taï National Park

More Information about the Taï-Chimpanzee-Project and the researchers' camp in the Taï National Park [more]

Interesting facts about chimpanzees

  • Chimpanzees mostly live in tropical rainforests, yet they can adapt to different habitats and – unlike the other great apes species – are also found in the more arid tree savannahs.
  • The diet of chimpanzees consists mainly of fruit, yet they also eat leaves, herbaceous plants and meat. They fish for termites and ants, and hunt smaller monkeys.
  • Chimpanzees live in large groups that often comprise more than 50 individuals but sometimes split up into smaller groups that are in turn disbanded and rearranged.
  • Females normally leave the groups into which they were born and join other groups, while males remain in their original group.
  • Chimpanzee groups vehemently defend rather large home ranges against male intruders. Unfamiliar females, on the other hand, are usually accepted into the new group. The purpose of this territorial behaviour is to protect the females and their offspring and to secure the food supply. A group usually consisting of several adult males regularly “patrols” the area to watch for enemies. While on the lookout, they move as quietly as possible.

Research in the jungle

Field research at the Ivory Coast

West Africa, the Republic of Côte d’Ivoire, Taï National Park, near the Liberian border: a twelve-hour car ride from the port city of Abidjan, three hours down a dirt road from the nearest village, lies the camp of the Max Planck researchers, in the middle of the tropical rainforest. For more than 30 years, this is where a team of scientists headed by the Swiss primate researcher Christophe Boesch have been studying the chimpanzees native to this jungle. Since 1997 the camp has belonged to the Leipzig-based Max Planck Institute for Evolutionary Anthropology.

The road – if you can even call it that, as during the rainy season even modern 4x4 vehicles struggle along this muddy track – leads to the North Camp. From here, a foot march until reaching the three actual research camps. But only after long stopover: Everyone who enters the camp – regardless of whether they are visiting for the first time or just came back from a short stay in the “outside world” – must first spend five days in the North Camp before he or she is allowed to set foot in the research area. This quarantine is an essential precaution, as diseases introduced by humans pose one of the greatest threats to the great apes.

In Taï National Park, the Max Planck scientists study three groups of chimpanzees comprising a total of about 100 individuals. These groups all live in neighbouring territories and are habituated, meaning they have grown accustomed to the presence of humans. One of the researchers’ goals is to comprehensively study and document the life of the Taï chimpanzees in their natural habitat. “Chimpanzees are similar to us in many ways,” says Christophe Boesch, Director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, who also founded the Taï chimpanzee project and has been serving as its president for many years. “Studying these similarities between us and our closest relatives in their natural habitat in Africa allows us to find out more about the evolutionary roots of culture. And culture, after all, is precisely what we humans consider to be one of the key elements of our identity as a species.”

Therefore, it ultimately comes down to the question of what makes humans human. Are we the only ones capable of developing traditions and cultures and passing them on to our descendants? Or do great apes also have social traditions, namely behavioural differences, which cannot be attributed to environmental factors or do not have a genetic origin, and are passed on from generation to generation within a group? The Max Planck Institute’s research station in Taï National Park is the ideal location to search for answers to these and more questions. Here, the scientists can observe chimpanzee groups that live in close proximity to each other in similar environmental conditions and share most of the same genes.

Yet for the researchers, another equally important goal is gathering data about the total number of apes, as well as the sizes and structures of the groups living in the National Park. This work is vital because even today nobody can really say for certain how many great apes still exist in the wild – the exact sizes of the populations of chimpanzees, bonobos and gorillas in Africa and orang-utans in Asia remain unknown. However, this basic information is urgently needed to scientifically evaluate the effects of natural changes or the success of environmental protection measures.

The North Camp, which now serves as a hygiene barrier between the chimpanzees and the outside world, is accessible via an unpaved, often muddy road. From there, scientists and visitors must walk to the three research camps on foot. Zoom Image
The North Camp, which now serves as a hygiene barrier between the chimpanzees and the outside world, is accessible via an unpaved, often muddy road. From there, scientists and visitors must walk to the three research camps on foot. [less]

The scientists from Leipzig are very familiar with the rainforest in Taï National Park. Some of them, like Christophe Boesch or Tobias Deschner, one of his closest colleagues, have been coming here for decades, and others – students and doctoral candidates – at least for several months at a stretch. Currently, about 20 researchers live and work in the camp: scientists, doctoral candidates, students and local field research assistants. The latter group also includes people who are in charge of supplying the researchers with provisions, such as a driver who delivers groceries once a week and runs all of the necessary errands in the nearest village or in the port city of Abidjan.

A veterinarian is also part of the resident team in the Max Planck Camp. In the North Camp he has scientific equipment at his disposal, including a simple molecular biology laboratory with a PCR machine for replicating traces of DNA. This allows him to regularly check and document the animals’ state of health and, if an animal is sick, quickly determine the cause. He also routinely checks every new arrival at the North Camp to make sure they do not accidentally introduce a pathogen for respiratory diseases that is particularly dangerous for the chimpanzees. These checks are necessary because even apparently healthy humans can carry these pathogens and thus trigger a life-threatening epidemic among the apes. Sick chimpanzees are usually not treated by the veterinarian, however, because, despite the presence of the researchers, the apes are supposed to remain wild animals whose lives should be influenced by the scientists as little as possible. An exception is only made for diseases that were introduced by humans.

Studying the behaviour of chimpanzees in the wild

In order to be able to study the behaviour of great apes in their natural surroundings, the researchers must get the animals accustomed to the presence of humans until they take little or no notice of them – a practice known as “habituation”. Yet before the scientists can begin with any of these preparations, they need to first find the apes. Statistically speaking, fewer than one chimpanzee lives in an area covering ten square kilometres in the Taï National Park - they will not just happen to cross one’s path. The researchers have no choice but to quietly and inconspicuously comb through the forest and search for clues revealing the animals’ whereabouts: discarded fruit skins, chewed up plants, footprints, chimpanzee excrement, abandoned sleeping nests in the treetops. Luckily for the scientists, chimpanzees often make a terrible rumpus – if they are heard, their calls can be followed for quite some distance.

Thus the researchers regularly make contact with the apes by cautiously approaching a group. Once the chimpanzees tolerate the researchers’ presence and no longer flee when they detect humans, the first goal has been reached. As time goes by, one group member after another starts building up trust and – often only after months of patient approaches – accepts the fact that humans are residing in their vicinity. Unlike gorillas, chimpanzees do not live in fixed groups, but in what are known as fission-fusion groups: new subgroups are constantly formed in the community, and these subgroups are in turn disbanded and regrouped. This means it can take a very long time for all individuals to get equally accustomed to the presence of humans until they no longer take any notice of them. It usually takes five years before a group of chimpanzees accepts the researchers’ presence as being “normal”, and before the animals behave as they would if they were alone – only then can the real research begin. This is another reason why the habituated chimpanzee groups in Taï National Park are of such great value for primate research.

The scientists are eager to observe the natural behaviour of the great apes; they want to learn about their “day-to-day life” in the jungle. That is why the researchers themselves always act in such a way as to influence the animals’ behaviour as little as possible. They remain strictly neutral towards the apes: they do not feed them, they do not eat in the presence of the chimpanzees, they never come into physical contact with the animals. And they do not play with their young, even if offspring are curious and themselves try to make contact with the researchers. But the researchers do follow the chimpanzees wherever they go and observe them.

The humans also do not attempt to become members of the chimpanzee group. On the contrary: they always behave in such a way that the apes tolerate their presence but otherwise ignore them. This is done not only for research purposes, but also for the scientists’ own safety. After all, if the apes were to regard them as one of their own, they would involuntarily become involved in fights for dominance within the group – and that would have fatal consequences for the researchers: an adult chimpanzee is significantly stronger than an adult human male.

The scientists take great care to make sure that the animals do not see them as food competitors. They do not eat any fruit or gather any nuts they find in the chimpanzees’ territory – for the humans, the abundant supply of food available in the jungle is off limits. They only eat food that they brought along. They are equally strict when it comes to discarding the food leftovers: any compostable material is carefully buried in the ground, while the rest is taken to the nearest village. “We don’t even spit in the forest anymore,” says Tobias Deschner. The risk of the animals becoming infected with human diseases is simply too high. Like in 2009, when numerous apes died as a result of a common cold epidemic.

In case of contact with chimpanzees, strict rules of behaviour and hygiene measures apply, such as the wearing of face masks. Zoom Image
In case of contact with chimpanzees, strict rules of behaviour and hygiene measures apply, such as the wearing of face masks.

Human diseases are one of the biggest threats facing the apes. Firstly, these primates are so closely related to us that they easily catch our diseases. And secondly, the immune system of great apes that never came into contact with humans is completely unprepared for the latter’s viruses and bacteria. That is why an infection can have potentially catastrophic consequences. This risk is particularly high in areas where logging companies, bush meat hunters or farmers use the jungle; yet even one close encounter with a researcher could be one encounter too many for a group of chimpanzees – for example if the humans transmit rhinoviruses. While the common cold is harmless for infected humans, it can easily lead to the death of an entire chimpanzee family. 

That is why in their dealings with the apes everyone in the camp who must adhere to strict hygiene rules, which – following bitter experiences in the past – they developed together with the Robert Koch Institute in Berlin. The five-day quarantine in the North Camp is just the beginning. Every single researcher or visitor must be vaccinated against numerous diseases; no one who shows even the slightest symptoms of an infection is allowed to enter the forest. Every observer must keep a minimum distance of seven metres between themself and the apes, and everyone must always wear a surgical mask – as unpleasant as that may be in 95 per cent humidity and temperatures well over 30° Celsius.

Roaming the jungle with the chimpanzees

Chimpanzees are known for having an excellent spatial memory – and the researchers studying the apes in Taï National Park were able to provide scientific proof of this capacity. The chimpanzees roam large areas and have no problems finding their way back to widely dispersed fruit trees or other places they like to frequent - unlike humans, who prefer to rely on modern technology for this. In the evenings, once the group of apes have decided on a place to sleep for the night and built their nests high up in the treetops, the observers make note of the exact GPS coordinates. This data makes it relatively easy to find the animals again in the morning, as the group usually does not relocate at night. Depending on how far away the sleeping nests are from the camp, the researchers have to get up at three or four o’clock in the morning, eat a hearty breakfast to gather their strength for the strenuous day that lies ahead of them, and then travel through the almost impassable jungle on foot for several hours. The most important thing is to get to the chimpanzees before sunrise. If the researchers are not there before the hungry apes awake and set off in search of food, they will most likely lose the group: chimpanzees travel great distances in short amounts of time. It can take days or weeks to find the group again. And only those who are able to decipher the most inconspicuous clues stand a chance of finding the apes in the forest. The special skills and extensive experience of the Ivorian field assistants plays a very important role in tracking down the animals. However, it is much easier to stick with the apes in the first place. That is why the researchers try to follow each of the groups under observation every day, if possible.

Each chimpanzee group is usually accompanied by two to three researchers, whereby the field assistants closely observe one particular individual and note down general observations, while the students or doctoral candidates focus on finding answers to a particular scientific question. But following a group of chimpanzees through the dense rainforest is easier said than done: due to the compact posture they assume by walking on their hands and feet, chimpanzees move with incredible speed and agility, while their tall, two-legged relatives stumble over roots or thorny bushes, get tangled up in vines and sometimes feel as if they are standing in front of an impenetrable green wall. Furthermore, they have to keep an eye on the animals, which – due to the light conditions in the jungle – blend in almost perfectly with the vegetation. No matter how hard they try, often all the researchers can do is listen for the chimpanzees’ calls and hope that the group will soon take a break.

The researchers’ daily routine in the National Park

Yet the researchers’ daily routine in Taï National Park involves more than merely observing the chimpanzees: the scientists also apply numerous indirect methods to learn more about the great apes. They look for sticks, stones and other objects that the chimpanzees have used as tools, and spend large amounts of time familiarising themselves with the animals’ habitat. They classify plants and analyse the apes’ food spectrum. They know exactly which types of fruit the apes are particularly keen on, and when the respective trees in the home range bear ripe fruit. The researchers also regularly collect samples of chimpanzee excrement, which are an especially valuable source of information - and not just about the animals’ dietary habits. Since the excrement also contains cells shed from the respective ape’s intestinal wall, the scientists can use the samples to isolate DNA and analyse the animal’s genes. This allows them to definitively determine how the individual members of a group are related to each other. Nowadays, for example, scientists no longer have to guess which male fathered which offspring – they can unequivocally prove the paternity in each case. This data, together with information about the animals’ hormonal balance obtained by analysing urine samples and the meticulously documented behavioural observations, allows the scientists to draw numerous conclusions about the familial and social behaviour of a group of chimpanzees. By no means are the young all fathered by the respective alpha male, for example; with incidence rates differing between groups, some of the young are actually the offspring of male chimpanzees lower down in the hierarchy. The researchers thus discovered that in chimpanzee populations there are various strategies which especially allow non-dominant males to successfully mate. The females also pursue their own personal strategies to seize the best opportunities for themselves and their progeny.

The DNA analyses carried out on excrement samples and hairs collected from abandoned sleeping nests are also important for carrying out a census on the chimpanzees living in this rainforest. With greater precision than ever before, the scientists are now able to say how many individuals live in a particular area of the forest, and whether chimpanzees that left the group, and have not been seen in a long time, are still alive.  

While some of these tests can be performed on site at the camp, most of the samples are preserved in liquid nitrogen, packed in dry ice and transported to Leipzig where they are analysed in the laboratories of the Max Planck Institute for Evolutionary Anthropology using state-of-the-art technology. Furthermore, all samples are put into long-term storage in one of the Institute’s biobanks, so that new scientific questions can be explored at a later date – perhaps even using analysis methods that have yet to be invented.

Contact with the outside world

Due to the strict hygiene regulations, it has become difficult for the scientists to simply leave the camp even for a short while and drive to the next village. Sacrificing five days of research for one beer at the bar – that is a loss no scientist is willing to take. Yet the camp’s residents are not entirely cut off from the outside world. Every three days, a stable Internet connection is set up using a satellite phone so that everyone can access their e-mails that have accumulated over the past few days. The researchers do not just use the e-mails to send copious amounts of scientific data back and forth, but also to stay in touch with family and friends all over the world. Even the African bush cannot thwart the advance of modern communications technology, and sometimes mobile phone reception in the camp isn’t all that bad: Until recently, it was necessary to drive to the nearest village 20 kilometres away just to make a call; today, depending on the camp, it’s enough to walk up the nearest hill or climb a ladder.

The research assistants are the “backbone” of the data collection effort. They work three-week shifts in the camp and follow the chimpanzee groups every day as they ramble through the rainforest. Zoom Image
The research assistants are the “backbone” of the data collection effort. They work three-week shifts in the camp and follow the chimpanzee groups every day as they ramble through the rainforest.

The local field assistants, on the other hand, leave the camp regularly. They return to their native villages in between their fixed three-week shifts at the camp. Apart from the work they do in the forest, they have set themselves another, equally important task: in their villages, they are the “ambassadors” of the chimpanzees. They talk to the villagers about their work, about everything they learned about chimpanzees, and especially about their surprising and fascinating experiences with individual animals. In so doing, they make a valuable contribution to protecting the chimpanzee groups from poachers. The field research assistants are not the only Africans on the Max Planck team. African students are often involved in the projects as well. It is hoped that once they become fully trained scientists, they will champion the protection of the National Park and continue the research projects – irrespective of the current political situation in the country, if possible. After all, nothing is more dangerous for the great apes than political turmoil: in a country ravaged by war or civil war, wild apes have no one to lobby for them.

Mud, continuous rainfall, virtually impenetrable vegetation, parasites – conducting research day for day, far off from any form of human civilisation is no easy feat, and can be unpleasant. Nevertheless, many scientists consider the rainforest to be paradise on earth. “The chimpanzees in the Taï forest are a part of my life. I have spent more time with some of them than I have with my closest friends. Experiencing them here in the wild, in their natural habitat, is pure bliss,” says Tobias Deschner.

Andrea Wegener

Image: Max-Planck-Institute for Evolutionary Anthropology / Christophe Boesch

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