Towards the “Complete Chimpanzee”

By Volker Sommer • Professor of Evolutionary Anthropology

The Gashaka Primate Project in Nigeria keeps embattled wildlife in the news – whether uplifting or gloomy. Founded 20 years ago by Volker Sommer, the project’s field research is particularly important to better understand our closest living relatives.

Chimpanzee infant – looking into an uncertain future

Researching a West African Wilderness

“So, what did you find out this time round?” I often endure this question when returning to Europe from a trip to Gashaka Gumti National Park – a remote and rugged wilderness in Nigeria’s mountainous Northeast, straddling the Cameroonian border.

However, the image of a lone researcher venturing to a little-known place to soon emerge with exciting scientific results is a misconception. Firstly, the success of field projects is positively correlated with for how long they are running – as much of what we want to know about habitat ecology can only be addressed by collecting long-term data, about, for example, how climatic cycles influence the reproduction of plants or animals. Mind you, with “long-term” I don’t refer to weeks or months. I mean years – or even decades. Secondly, much of today’s cutting-edge field research is combined with subsequent analyses of data and biological samples in off-site facilities that specialise in, you name it, virology, genetics, nutrition, geology, endocrinology or remote sensing.

A helpful way to understand the philosophy embodied by permanent field stations is to view them as out-door laboratories. As scientific director of such a “wild lab”, I need to ensure the uninterrupted collection of base-line records – which entails the rather mundane tasks of maintaining essential buildings, equipment as well as training local field assistants. I also need to assess and facilitate requests from short-term investigators aiming to pursue a specific agenda during a limited stay in the field. These hopefuls include undergraduate, master and PhD students, postdocs and established academics as well as volunteers who yearn to gain open-air experience in research and conservation-related programmes. 

Baboons are highly adaptable – but many primates are not

Temporary visitors pay a modest “bench fee” to the project, thus subsidising accommodation and kitchen amenities, supplies of cooking gas, water and power as well as field assistant expertise. These fees also contribute to a linked scholarship scheme that fosters tertiary education of Nigerians in technical training institutes, community colleges and universities. Our project also enables direct knowledge transfer. For this, Nigerian fieldworkers and those from developed countries work alongside each other, which introduces Africans to state-of-the-art methods not yet available to them and Westerners to indigenous concepts and ways of life.

So far, field workers hailed from two dozen nations (Argentina, Austria, Brazil, Cameroon, Canada, France, Germany, Greece, Israel, Italy, Ivory Coast, Japan, Mexico, New Zealand, Nigeria, Portugal, Spain, Sweden, Switzerland, Taiwan, The Netherlands, UK, USA). They were affiliated with 24 universities, 5 research institutes, 3 zoological societies and 4 conservation NGOs. Over 20 years, this flurry resulted in 220 tangible outputs – that’s one per month! Overall, students produced 4 undergraduate and 39 master’s dissertations as well as almost 20 PhD theses. The harvest also encompasses 22 reports (“grey” publications), 14 pieces of popular writing, 4 artist residencies with subsequent exhibitions, 4 documentaries, 45 research abstracts, 2 books and – major currency of scientific credibility – 68 articles in edited volumes and journals. With this, the scientific yield of the Gashaka Primate Project ranks amongst the most successful of any permanent field stations on the globe.

Amidst widespread Anthropocene take-overs, the mosaic of rain forest and savannah in the Gashaka area is still a relatively safe haven for a dreamlike assemblage of flora and fauna. Our publications have covered creatures such as fungi, flies, springtails, driver ants, termites, honey bees, frogs, birds, wild pigs and antelopes, plus our “staple order”, primates, with species such as black-and-white colobus, olive baboons, mona, putty-nosed and tantalus monkeys. We have published on a wide array of topics ranging from vocal communication, ontogenesis, biased hand use, play behaviour, predation, seed dispersal, stress and parasites to phylogeography, vegetation mapping, and ethno-botany. Sadly, we may well be the last generation than can scientifically capitalize on such a symphony of biodiversity.

Research team with a global make-up of students, conservationists, scientists and local field assistants

The Panafrican Chimpanzee

Anthropocentric as we happen to be, most headlines about our research output are grabbed by chimpanzees – given that Gashaka harbours the largest surviving population of the rarest and genetically most distinct type of this ape, the Nigeria-Cameroon subspecies (Pan troglodytes ellioti). Our own observations are systematically combined with those from other ape study sites across Africa. As project director, I have been lucky to be a contributing co-author to many of the resulting outputs – often in high-impact journals such as Science and Current Biology. For this, we cooperate across large international teams that may include up to 80 other experts in primatology, genetics, microbiology, statistics or conservation biology. 

Of particular importance is the “Pan African Project” conceived at the Max-Planck-Institute for Evolutionary Anthropology at Leipzig / Germany (panafrican.eva.mpg.de). “PanAf” alludes not only to the genus name for chimpanzees and bonobos – Pan –, but also to the pan-African collection of standardized records across 30–40 ape populations, which include camera traps and gathering of biological samples. The findings – which at times also cover the other African apes, gorillas and bonobos – are unparalleled in their breadth, as evidenced by summaries of some recent and current findings. 

Whatsuphere? Gashaka chimpanzees looking at a video-trap

Chimpanzee Culturecide Humans, depending on where they live, develop different traditions, abilities and customs. Chimpanzees exhibit a similar degree of “cultural variation”, with respect to, for example, tool use, communication or feeding habits. Comparing 31 chimpanzee behaviours across 144 social units comprising their entire geographic species range revealed the sad fact that in areas of high human impact, behavioural diversity was reduced by 88%. Thus, the dominant mammal commits culturecide of its iconic relatives. (Kühl, Kalan et al. 2019. Human impact erodes chimpanzee behavioural diversity. Science 363(6434):1453-1455 DOI: 10.1126/science.aau4532)

Candid Camera When confronted with video-trap devices installed around research sites, wild apes may react to them either alarmed or curious – with interesting species differences. Compared to chimpanzees and gorillas, who exhibit a stronger looking impulse towards the lenses, bonobos were neophobic, i.e., reacted more fearful and cautious. This may be because bonobo societies are female-centred and rather egalitarian compared to other apes where a dominant male may default as the leader. However, the three species also showed similarities in novelty responses, as the apes looked at cameras longer when they were young, were associating with fewer individuals, and did not live near a long-term research site – which would have increased familiarity with human activity. (Kalan et al. 2019. Novelty response of wild African apes to camera-traps. Current Biology DOI: 10.1016/j.cub.2019.02.024)

Rock-and-Rowling Despite decades of often close-up observations, chimpanzees can still surprise – as we realised when sifting through thousands of video-trap records. Thus, in four locations in West Africa, the apes exhibit the rather bizarre habit of banging and throwing rocks against trees or tossing them into trunk cavities. Over the course of time, heaps of stones may form. The accumulations are similar to cairns – human-made stone mounds found in many parts of the world. While the reviewers of the paper cut out the suggestion that chimpanzee rock throwing is a precursor of human rituals, archaeologists will surely have to revisit the idea that every heap of stone has been produced by thoughtful humans. (Kühl et al. 2016. Chimpanzee accumulative stone throwing. Scientific Reports 6: 22219)

Make-shift camp while surveying unknown forests

Sleepless Nights “In the jungle, the mighty jungle / The lion sleeps tonight”. While the king of the jungle dreams, chimpanzees might move through the dark – as evidenced by camera-traps planted at 22 sites across Africa. At 18 locations, the apes were at least occasionally up to something, most frequently during twilight. They are leaving their night nests with greater probability when it is hotter and when surrounded by dense jungle. Still, night-walking is rare – which places chimpanzees into the human-like pattern of adhering to a “consolidated sleep”. (Tagg et al. 2018. Nocturnal activity in wild chimpanzees: evidence for flexible sleeping patterns and insights into human evolution. American Journal of Physical Anthropology 166: 510–529)

Not Just Gut Feelings Faecal samples were collected to extract symbiotic single-celled protists that populate the large intestines and aid the digestion of fibre. Named after the hair-like vibrating structures that allow for their movements, such ciliate organisms have different genetic markers, reflecting the geographical distribution of chimpanzees. Ciliate genetics can not only shed light on how chimpanzee subspecies might have evolved from a common ancestor. It also suggests that the elimination of these particular organisms in the guts of modern humans might be connected to changes in diet once fire was used to prepare food. (Vallo et al. 2012. Molecular diversity of entodiniomorphid ciliate Troglodytella abrassarti and its coevolution with chimpanzees. American Journal of Physical Anthropology 148: 525–533)

Intestines are Eco-Systems, Too The intestinal microbiome is essential for health, contributing to digestion of foods, immune development and inhibition of pathogen colonization. However, the principles of how animal-associated communities of different bacterial strands are structured is largely unknown. To make progress, the study looked at genetic data of bacterial lineages found in 64 species of bilaterally symmetrical animals – from flies to whales and including chimpanzees. This investigation was the first to document the expected correlation that larger animals harbour a greater number of bacterial lineages per gut sample. It suggests that species richness and thus niche complexity increases with gut size. The analytic methods may be useful in assessing colonization mechanisms in human disease states and in evaluating the invasion of human-associated bacteria into global ecosystems. (Sherrill-Mix et al. 2018. Allometry and ecology of the bilaterian gut microbiome. mBio 9: e00319-18)

Fieldwork can be heavy lifting

Sustaining the Future Human activities are sadly known to threaten the biodiversity, even within allegedly protected zones. Based on data for almost 100 tropical forests in 15 African countries, the analyses lead by Anthropology PhD student Sandra Tranquilli assessed which specific human activities influence the survival prospects of these areas. Agriculture and logging were found to be particularly destructive. Protective efforts such as law enforcement, tourism and research can make a difference, but only if tied to a long-term strategy. This corroborates experience from the Gashaka Primate Project that impact on conservation will be greater once the necessary infrastructure is built up and sustained. The finding quantifies the obvious: Short-term activism is not going to make a difference – only a structured approach will. (Tranquilli et al. 2014. Protected areas in tropical Africa: Assessing threats and the impact of conservation activities. PLoS ONE 9: e114154)

The last featured publication highlights why research into wildlife is not purely academic. Instead, even blue sky investigations can have a tangible impact of deterring illegal activities in core study areas and those surveyed for biodiversity. Research also informs conservation management strategies. Moreover, many students who work at a field site later choose a career in nature conservation. Thus, the physical and emotional challenges as well as the intellectual outcomes of research are a powerful motivator to work towards the preservation of increasingly fragile wildernesses – whether at Gashaka or elsewhere.

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