Humans frequently collaborate and share resources with individuals from diverse social groups, even in the absence of immediate benefits. Surprisingly, this behavior, once thought to be exclusive to humans, has been observed in bonobos, according to a recent study.
This type of cooperation is considered crucial to the advancement of human civilization. Similar to humans, bonobos demonstrate the ability to establish connections and cooperate with nonrelatives from different social groups, providing valuable insights into the evolutionary conditions that led to the development of large-scale human societies. Researchers from the German Primate Center and Harvard University conducted a study, and the results were published in Science on November 16.
Both chimpanzees and bonobos live in social groups that may include individuals with no close familial ties. However, bonobos exhibit a more tolerant attitude toward other groups compared to the territorial and aggressive chimpanzees. Bonobos engage in grooming, food sharing, and even adopt young individuals from unrelated groups. The extent of this cooperative behavior among bonobos remained unclear until this study.
The research focused on two bonobo groups in the Congo's Kokolopori Bonobo Reserve, monitoring their interactions over a two-year period. Instances of grooming, food sharing, and alliances formed between members of different social groups were meticulously recorded by the researchers.
Despite the presence of conflict and competition, the bonobos exhibited cooperative behavior during their interactions. Approximately 10% of grooming interactions and 15% of alliances formed to attack a third individual involved bonobos from different social groups. Additionally, 6% of all food sharing occurred across groups.
The researchers emphasized that this cooperation was not arbitrary; individuals engaging in cooperative behavior within their own group were more likely to interact with bonobos from other groups displaying similar tendencies. Notably, this cooperation did not seem solely driven by immediate reciprocation, as only 14% of instances where food was shared with another group resulted in reciprocation.
The findings build upon previous evidence of bonobos in captivity displaying comparable behavior, suggesting that cooperation with nonrelatives across social groups may be intrinsic to the species. While some animals cooperate with relatives to promote the survival of their genes, cooperating with nonrelatives offers a more indirect evolutionary benefit.
Bonobos now join a select group of species, including vampire bats and humans, known to participate in food sharing between unrelated individuals. This behavior, crucial in human evolution for sustaining societies during food shortages, underscores the distinctive aspects of bonobo cooperation.
The study prompts inquiries into the evolutionary origins of cooperative behavior in humans. Despite humans sharing a common ancestry with both chimpanzees and bonobos, it remains uncertain whether early human ancestors exhibited rigid territorial behaviors like chimps or a more relaxed attitude akin to bonobos.
Furthermore, the research challenges the notion that extensive, long-term cooperation between groups necessitates the heavy influence of cultural factors and social norms. The bonobo study suggests that such cooperation can manifest in a relatively simple system, akin to humans.
While the study primarily focused on two bonobo groups, researchers acknowledge the potential influence of a cultural component on their behavior. Subsequent studies involving additional bonobo groups may yield insights into the presence of social norms among these primates.