The population of chimpanzees on Rubondo Island
has been mentioned in previous articles: how they came to be there by the efforts of the great conservationist Professor Bernard Grzimek. From a core group of 16 released back into the wild over several years in the 1960s, this community now numbers around 40 individuals, and they are all wild-born. Dr. Bertolani will now be at the forefront of a project to habituate these wild chimps on Rubondo Island National Park.
This presents a unique opportunity for studying their behaviour, population dynamics and even genetic diversity, but in order to do that, these wild chimps must first be habituated to a human presence. In a completely natural state, chimpanzees have an innate fear of humans, and will flee at the first sight of people, as Dr. Jane Goodall famously noted in recording her attempts at habituating the chimps at Gombe Stream, which was the first time this had been done.
The first thing you notice about him is the tattoo on his brow that makes him look remarkably like a chimpanzee. In fact, he was given this tattoo by a tribe of Mentawai hunters in Sumatra, Indonesia while he lived among them in 1990. The next thing you notice is the intensity of his gaze, both inquisitive and penetrating at the same time, able to notice and interpret the subtlest nuances of body language, facial expressions and non-verbal communication clues from his subjects. Both of these must be of huge benefit to someone studying anthropoid apes, and judging by his success, they must be.
He has a great depth of experience in his field, having been involved in chimp studies in several research projects across Africa, and in two cases he was directly involved in habituating the animals to human presence before they could be studied further by direct observation.
In his first study, he went to Taï National Park in Cote d’Ivoire, where the chimps had been part of a habituation project for four years, and at that time, one female, Zora, was tolerating a human presence. After a year, he had successfully habituated several more individuals, mostly males, which then led to the rest of the study community becoming accustomed to human observers. This led to the direct observation of their behaviour of nut-cracking, using a rock and a stone anvil. This might not sound like an earth-shattering behavioural trait, but it has huge implications in the fields of biological anthropology and psychology. This behaviour was deemed to be cultural: studies since the 1980s have shown it only occurs among specific groups of chimpanzees in West Africa, and isn’t found elsewhere. This is especially obvious where populations are separated by rivers, where on one side they have the “knowledge” of nut-cracking, on the other they don’t.
He wrote his dissertation for the University of Rome on the habituation process and behaviour of a female that reared an adopted infant in addition to her own baby, which was unusually altruistic behaviour not commonly encountered in the wild.
Then, during a sojourn of several years, he studied turtles in South America and worked for an institute of statistics in his hometown, Rome.
Eventually, Africa and chimpanzees called him back, and in 2004 he found himself in Senegal, once again working on habituating a community that lived in the arid, mosaic-savannah habitat of Fongoli. This site had particular interest to researchers as it was very similar to the environment that created early man, and the behaviour of chimps there might lead to vital clues to our understanding of our own early development.
Dr. Bertolani also worked on the habituation of the chimps, a process that had started several years before his arrival. After many months of sometimes very frustrating work, he says, he managed to win over the acceptance of the group, until he was able to follow them and observe their behaviour. It was at this point that he made an astounding discovery. Several of the chimps, mostly females and adolescents, were making spears by selecting a branch, stripping off the leaves and sharpening the point with their teeth. They then used these spears to hunt bushbabies, small nocturnal primates that hide in tree crevices during the day. This was the first recorded instance of a non-human primate regularly using tools to actively hunt vertebrates. The discovery caused a sensation around the world, and this behaviour has now been observed many times and been the subject of a National Geographic documentary. Another observation he made was of the chimps here bathing in pools of water to escape the terrific summertime heat, which was extraordinary in itself, as chimps are notoriously afraid of water.
For his next project, Dr. Bertolani found himself in Kibale National Park, Uganda, where a group of chimpanzees where being studied by Professor Richard Wrangham. This group had taken ten years to habituate, and Dr. Bertolani suspects this was due to the fact that groups of people used to venture into the forest where the chimps were, as opposed to a single person, which is the method he prefers. It was here that he worked on his PhD. study for the University of Cambridge, which was on the home-range use and spatial orientation of the chimps in the forest, i.e. how they must have made a mental map of their environment in order to navigate their territory in search of food and water.
His habituation project on Rubondo Island National Park is set to become the subject of a new National Geographic documentary – in the next blog post Dr. Bertolani’s will discuss his plans for the chimpanzees, and how he will go about the enormous task that awaits him.
To read more about Rubondo on our blog please click here.