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Episode 361: Bonobos are Back

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The super intelligent and socially advanced Bonobo (image from Dorling Kindersley)

Bonobos are widely renowned to be the most intelligent and socially complex primate on earth, and are our closest living relatives, alongside the chimpanzee, both in the genus Pan. First recorded in the 1920’s by German Biologist Heinz Heck and Austrian Biologist Eduard Paul Tratz, the name is thought to have derived from a misspelling of the word Bolobo on a shipping crate from the town of Bolobo on the Congo River, where the first specimens and several skulls were collected. In 1928, biologists determined that Bonobos were distinct from their close relatives chimpanzees from studies of their skull morphology. By the 1950’s several field studies had been conducted, and primatologists began to determine major behavioural differences between the two primates, with bonobos generally considered to be far more peaceful than their more aggressive chimp relatives. 

It is estimated that our distant human relatives first split away from bonobos around 8 million years ago, and then split from chimpanzees around 2 million years ago. Scientists largely think this split occurred due to the acidification and spread of savannah habitat that split populations up, leading to them evolving in isolation of each other. The very earliest Pan genus fossils were found in Kenya and dated to the Pleistocene era, around 7,700,000 years ago. Bonobos are very similar to the ancient human ancestor Australopithecus, and there is a hypothesis that bonobos experienced a very similar evolutionary period to humans, leading to the reduced aggression that is seen in the species today. 

Big brained bonobos: Intelligence and Sociality 

Bonobos are famous for displaying complex behaviour, showing altruism, compassion, empathy, kindness, patience and sensitivity. Although some primatologists argue this is only based off behaviour studied in captivity, but a 2014 study of wild troops of both bonobos and chimps found that the chimps displayed far more aggression. 

A bonobo matriarch with her infant (image from the New York Times)

Bonobos live in matriarchal societies, usually led by one experienced matriarch and a team of high ranking males and females. The matriarch is the leader and decision maker for the whole troop, and rather than achieving this dominance through violence and aggression, the female gains the position through experience, age and the ability to form friendships and alliances with other females in the group. Although generally females are more dominant, males can achieve high status, particularly if they partner with the dominant female. Males often take on the role of protector, scouting and alerting the group of the presence of predators. 

In contrast to many other animal societies, bonobo males are philopatric, meaning they will remain with their natal group for their whole lives, whilst it is the females who immigrate to new groups. This is different to animals like elephants for example, who exhibit female philopatry, in that the females remain with their natal group and the males disperse away to breed. Within bonobo societies, males can gain status from their mothers, and their mothers will protect their sons and support their role within the group, increasing the chances of offspring with her genes. Adoption is a phenomenon that has been observed in bonobo society, with both males and females known to foster from outside their community. For example in one reserve, primatologists observed an older male adopt his orphaned younger brother, raising him and teaching him vital skills for survival in the wild. 

A group of bonobos grooming to strengthen their social bonds (image from Inside Science)

Bonobos haven’t gained a reputation for kindness and empathy for no reason. Aggression, both within and between groups, is incredibly rare, even when different groups are competing for the exact same resource. Bonobos are not territorial, and will not become aggressive if members of another group stray into their range. Different groups are even known to collaborate with each other in the Kokolopori Bonobo Reserve, grooming each other, sharing food and defending each other from predators. Behavourial scientists hypothesize that bonobos are more cooperative and peaceful because they live in habitats with abundant vegetation, reducing competition between them and allowing them to spend time in large groups, socializing and developing their skills and behaviour. 

Scans of bonobo brains reveal that they are evolved differently to chimps, with more development in regions that control emotions and behaviour. Bonobos join a very small group of animals, such as dolphins and elephants, that can pass the mirror self recognition test, indicating that they are capable of recognising their reflection as that of themselves and not the presence of another animal. When recordings of their facial expressions are played to people, we are capable of recognising them and what they mean. Bonobos also display an incredibly rare feat that is only seen in humans; they will use the same call for different things, and other bonobos in the group will interpret these calls based off context clues. At the Great Ape Trust, two bonobos Kanzi and Panbanisha have even been taught to communicate with a piece of equipment called a lexigram keyboard, a keyboard consisting of symbols, and can respond to spoken sentences and questions. 

Bonobo trainer Sue Savage Rumbaugh using a lexigram with Bonobo Kanzi (image from the Great Ape Trust)

Primates in trouble

Bonobos are found throughout the  primary and secondary forest of the Congo Basin, an area that has experienced intense conflict and socio-political upheaval. Bonobos are classified as endangered on the IUCN red list, and are considered to be one of the most endangered primates. 

Poaching is a serious threat to the bonobo, with a demand for their meat for the bushmeat trade, and their body parts for traditional medicine. Hunting can be highly efficient with the use of snares and automatic rifles, and as populations decline, poachers move further and further into undisturbed forest in search of bushmeat. In many areas, locals consider the killing of bonobos to be a serious taboo, but years upon years of civil unrest, the influx of immigrants fleeing conflict and the breakdown of social law and order has meant that this tradition has been almost entirely lost. Many poachers come from far afield and don’t feel the same social pressures locals would towards the hunting of bonobos. During the vicious Congo wars, the bushmeat trade increased rapidly, and the presence of heavily armed militias in the region meant that hunting could be conducted on a much wider scale. To compound these issues, conservationists and rangers, no matter how dedicated, were pushed out of the reserves by the intense violence and their projects and interventions abandoned. In many parts of Africa, including the Congo, there is a strong cultural attachment to bushmeat that will be incredibly difficult to break. Surveys conducted in Kinshasha found that even if household income and access to food increased, citizens would still prefer to eat bushmeat, despite the health risks and environmental damages it poses. 

A bushmeat market in Africa, where primate meat if often sold (image from Newsweek)

Unrestricted hunting is particularly damaging for Bonobos as they have a very long interbirth interval and don’t even reach sexual maturity until they are 13-25 years old. Additionally, when a bonobo dies, often this will lead to the death of a dependant infant, especially amongst females. The infant will often die from starvation, be killed after the mother or possibly kidnapped and sold into the illegal pet trade. 

Not only facing poaching, bonobos are also dealing with significant loss of their habitat to agriculture, road construction and other human developments. The highly destructive practice of slash and burn agriculture is very common in the Congo, and the long years of civil strife in the region have massively exacerbated forest loss. Studies of trends in habitat loss found that forest destruction was twice as high during conflict periods. This loss of habitat can force bonobos into close contact with humans, and there is a unique problem that primates face when close to civilisation; the spread of human-borne disease. The spread of respiratory disease is common, and even more severe disease, like the deadly ebolavirus can burn through bonobo groups like wildfire. Bonobos are particularly prone to outbreaks with their close social contacts between and within groups. 

An oil palm nursery that has caused significant deforestation in the Congo Basin (image from Greenpeace)

Quite aside from the fact that they are incredible animals and their loss would be devastating, if bobos were to be extirpated from their habitats it would have a devastating impact on the ecosystem. Bonobos have an incredibly important role as seed dispersers as the second largest frugivores behind elephants. They ingest around around nine tonnes of seeds from 91 species of plant, which are then carried in their digestive tract for 24 hours, traveling many kilometres away from the parent plant. Studies have even shown that seeds that have passed through bonobo guts germinate better than those not ingested by the primates. They have a unique niche in the ecosystem, different to other seed dispersers like elephants, as they ingest the seeds of different plants and travel to different areas. Scientists estimate that they disperse as much as 40% of the seeds in the forest! 

Conservation optimism

Bonobos are facing an uncertain future, but they are not facing it alone. Although legal protection for Bonobos can be intermittently enforced, they are listed under Appendix 1 of CITES, banning all trade in bonobos or their body parts. Many bonobos are found in protected parks, however these areas are poorly controlled and lacking in resources to protect them. 

In 2012, the IUCN published a conservation strategy for the Bonobo, which includes recommendations for increasing training and wages for forest department staff and improving infrastructure in these protected parks. Additionally, conservationists are aiming to collaborate with the Congolese army who can help to improve the spotty law enforcement in the region and provide essential equipment and weapons for rangers to protect themselves. Operation Bonobo is a government backed project aiming to confiscate all military grade weapons still circulating in the country from the brutal 2012 conflict, which would help to curb poaching. Another aim of the project is to establish new protected areas and staff them sufficiently to allow protection of not just bonobos but other species that rely on them. The engagement of local people is also important, improving their economic prospects and allowing them to move away from poaching as an income source. 

A bonobo orphan being cared for by a dedicated staff member from charity Lola Ya Bonobo (image from Friends of Bonobos)

One of the most important charities fighting for bonobos is Lola Ya Bonobo, the world’s only organization that provides sanctuary for orphaned bonobos and rehabilitates and releases them back into the wild. They also educate and raise awareness among locals, showing them their rescued bonobos so communities are aware of the incredible animals they share their country with. Lola Ya Bonobo understand that the roots of poaching and the bushmeat trade stem from extreme poverty and they work with other organizations to increase access to food, education and adequate health care for impoverished rural communities. They work to provide alternative streams of income for locals and conduct vital research in the Congo, monitoring bonobo populations and the illegal trade. They truly do incredible work on the ground in the Congo, and you can learn all about them at Friends of Bonobos | We save bonobos and their Congo rainforest home. They even have a great online shop if you fancy treating yourself or a loved one, and helping to save bonobos in the process!

Awesome videos!


Beaune, D. (2012) ‘The ecological role of the bonobo. Seed dispersal service in Congo Forest.’ Research Gate

Furuichi, T. (2011) ‘Female contributions to the peaceful nature of bonobo society.’ Evolutionary Anthropology

Hare, B. Kwetuenda, S. (2010) ‘Bonobos voluntarily share their own food with others.’ Current Biology

Hart, J.A. Grossman, F. Vosper, A. and Ilanga, J. (2008) ‘Human hunting and its impact on the bonobo in Salonga National Park.’ The Bonobos: Behaviour, Ecology, and Conservation

McBrearty, S. Jablonski, N.G. (2005) ‘First fossil chimpanzee’. Nature

Nackoney, J. Molinario, G. Potapov, P. Turubanova, S. Hansen, M.C. and Furuichi, T (2014) ‘Impacts of civil conflict on primary forest habitat in northern democratic republic of Congo.’ Biological Conservation

Nackoney, J. and Williams, D. (2012) ‘Conservation prioritization and planning with limited wildlife data in a Congo Basin forest landscape: assessing human threats and vulnerability to land use change.’ Journal of Conservation Planning

Pan paniscus (Bonobo) (iucnredlist.org)

Patterson, N. Richter, D.J. Gnerre, S. Lander, E.S. and Recih, D. (2006) ‘Genetic evidence for complex speciation of humans and chimpanzees.’ Nature

Prufer, K. Much, K. Hellman, I. Akagi, K. Miller, J.R. Walenz, B et al (2012) ‘The Bonobo genome compared with the chimpanzee and human genomes.’ Nature

Samuni, L et al (2023) ‘Cooperation across social borders in bonobos.’ Science

Surbeck, M. Hohmann G. (2018) ‘Affiliations, aggressions and an adoption: male-male relationships in wild bonobos.’ Oxford Scholarship

Surbeck, M. Mindry, R. Hohmann, G. (2011) ‘Mothers matter! Maternal support, dominance status and mating success in male bonobos.’ PNAS

Tokuyama, N. Toda, K. Poiret, M.L. Iyokango, B. Bakaa, B. and Ishizuka, S. (2021) ‘Two wild female bonobos adopted infants from a different social group at Wamba.’ Scientific Reports

Wilson, ML. Boesch, C. Fruth, B. Furuichi, T. Gilby, I.C. Hashimoto, C et al (2014) ‘Lethal aggression in Pan is better explained by adaptive strategies than human impacts.; Nature 


November 08, 2023
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