The conclusions arose from daily observations of within- and between-group interactions of 31 adult bonobos, living in two communities called Ekalakala and Kokoalongo, all within the Kokolopori Bonobo Reserve in the Congo. Surbeck initiated the project in 2016 and, together with Samuni, has been working with Congolese partners and local villagers to collect data.
For the study, Surbeck, Samuni, and a team of local trackers focused on three cooperative behaviors: food-sharing; grooming; and forming alliances, which consists of joint action against a common opponent.
They found that certain individuals exhibited these acts outside their social bounds with others who would be likely to return the favors. Although bonobos are known for being a peaceful species, compared with their more warring chimpanzee cousins, the researchers found that the bonobos were not random in their benevolence.
“They’re not similarly nice to everybody,” Samuni said, noting they formed preferences for some and not others.
“The extreme tolerance we observed between members of different bonobo groups paves the way for pro-social cooperative behaviors between them, a stark contrast to their sister species, the chimpanzees,” she added.
Humans and bonobos share 99 percent of their DNA. Observing the animals in their natural environment can offer a window into our evolutionary past, the researchers say. Work at the preserve takes years of remote coexistence with the bonobos; habituation of the animals to a human presence has been key to making the studies successful, Surbeck said.
Surbeck’s team works closely with local partners, including the conservation organization Vie Sauvage, the Congolese Conservation authorities (ICCN), and the Bonobo Conservation Initiative, to gain support and permission to work in the country and on the community reserve.
“Long-term research sites don’t always quite get the recognition they deserve, in terms of what they contribute to both basic data collection and serving as a platform for other scientists, as well as for the conservation of the species,” Surbeck said.
Bonobos are a critically endangered species, with only a few thousand left in the wild, yet they represent a key comparative model to human social systems, “a rare opportunity to reconstruct the ancestral conditions of human large-scale cooperation,” according to the paper.