Monkey Monday | Bonobos Share With Strangers

Baby bonobos share papayas. Photo from Jingzhi Tan.

... primatologists know that great apes help and voluntarily share food with other group mates (acts that indirectly benefit themselves). But strangers? Such a behavior is unheard of amidst species that often compete aggressively with other groups and even murder foreign individuals.

Researchers from Duke University decided to challenge the great ape’s bad sharing rep, seeking to discover whether or not our furry relatives may also have a propensity for partitioning goods with animals they do not know. The scientists chose bonobos–a type of great ape sometimes referred to as a pygmy chimpanzee–for their study. Compared to chimpanzees, bonobos possess a relatively high tolerance for strangers, so they seemed like a logical candidate for investigations into the nature of sharing.

At a bonobo sanctuary in the Democratic Republic of the Congo, they enrolled 15 wild-born bonobos orphaned and rescued from the illegal wildlife trade in four experiments. In the first experiment, the researchers led a bonobo into a room piled high with delicious banana slices. Behind two sliding doors, they placed either a friend of the main bonobo or a stranger (a bonobo unrelated and unknown to their main research subject). The bonobo with the bananas could chose to eat the food all on its own, or open the sliding door and invite both or either the friend or stranger to join in. In the second experiment, they placed only one bonobo–either the friend or stranger–behind a door and left the second room empty.

The results, which they describe this week in the journal PLoS One, confounded the researchers. In more than 70 percent of the trials, the bonobos shared their food at least once. They preferred to release the stranger over their group mate, and the stranger in turn often released the other bonobo, even though that meant splitting the food three ways and being outnumbered by two bonobos that already knew each other. They ignored the door leading to the empty room, showing that the novelty of opening the door was not motivating their behavior.

So, were the bonobos willing to share their food with strangers because of an overwhelming desire to interact with the unknown apes, or were they motivated by a sense of altruism? The researchers set up two more experiments to find out.

Read more at Smithsonian | Surprising Science