Researchers Jingzhi Tan and Brian Hare from Duke University found that the bonobos' behaviour was at least partially driven by unselfish motivations, since the animals helped strangers acquire food that was out of reach even when no social interaction was possible as a result of helping them.
However, their generosity had its limits: They would not share food in their possession if no social interaction was possible.
Though the study subjects were all bonobos that had been orphaned by the bushmeat trade in Congo, they showed no significant psychological differences from bonobos that had been raised by their mothers.
According to the researchers, the evolution of generosity in these apes, our closest living relatives. They suggest that the behaviour may have evolved to allow for the expansion of individual social networks.
"Our results show that generosity toward strangers is not unique to humans. Like chimpanzees, our species would kill strangers, like bonobos, we could also be very nice to strangers.
Our results highlight the importance of studying bonobos to fully understand the origins of such human behaviours," lead author Tan said in a statement.
