Bonobos are happy to help complete strangers get food, and they'll do it without even being asked, a study published in Scientific Reports has found.
Duke University researchers gathered 16 wild-born bonobos from the Lola Ya Bonobo sanctuary in the Democratic Republic of Congo and led them one at a time into one of two adjacent rooms divided by a fence. On the opposite side of the fence from where the bonobos were was an apple hanging by a rope. The dangling fruit was clearly visible to the bonobos, but inaccessible.
Unless, that is, they climbed the fence and released a pin that would allow the apple to drop within reach of any nearby bonobos. If there were other bonobos in the room, a bonobo was four times more likely to climb the fence and release the apple than if the room was empty. They didn't even need to be asked by another bonobo to do it.
These findings complement a 2013 study performed by the same researchers that found that bonobos will also share their food with strangers.
This degree of altruism in the bonobos may be unconscious. In another experiment, 21 bonobos watched videos of other familiar bonobos yawning or making other natural expressions or they saw videos of bonobos from the Columbus Zoo doing the same actions. The yawns of unknown bonobos were just as contagious as those of the known bonobos. Researchers aren't sure if this just an empathetic response or a social nicety, but it does indicate that bonobos have a positive response to complete strangers.
The researchers conclude that much of this behavior is likely an evolutionary trait. When the reach adulthood, female bonobos leave their original group to find a new one. Being nice to new bonobos — like getting and giving food without being asked — can help a bonobo be accepted into a new group. Basically, bonobos like to make a good first impression, and being kind is an excellent first step.