A bonobo is placed in an enclosed area with a pile of food on the floor. He can see a door that connects the enclosure with another room and a second bonobo outside of the the enclosure looking intently at the food. The second bonobo calls and reaches for the food but cannot touch it. The first bonobo has a choice: to eat all of the food by himself, or to share it with the second bonobo. Which does he choose?
The bonobo, an endangered species of ape, is equally related to the human as chimpanzees. Although little is known about the species, there have been many recent studies on this particular ape. Bonobos are located to the south of the Congo River in only one country – the Democratic Republic of the Congo. Bonobos look similar to chimpanzees; however, they have a more slender shape and a black face. In bonobo communities, the females have social dominance over the males. Although they do have specific group areas, bonobo territories may overlap. They are the only ape that doesn’t kill other primates.
JingZhi Tan and his colleagues at Duke University began researching bonobo actions. They formed a test where a bonobo has an opportunity to share his food with a stranger bonobo. They found that bonobos preferred to share their meal than to eat it alone.
After this first successful study, Tan and his team wanted to find more supporting evidence. They went to the Kinshasa sanctuary for bonobos in the Democratic Republic of the Congo and designed a new experiment that would test to see if a bonobo preferred to share the food with a stranger bonobo or a bonobo from its community. The test was similar to the first experiment. The subject bonobo was placed in a center enclosure with two doors on either side and a pile of food in the middle. On either side, there was another bonobo in a separate room (one was a stranger; the other, a group member). A wooden one-way key was placed in each of the doors.
In the test, Tan found out that all of the bonobos opened a door to share their food, and nine of the 14 bonobos decided to eat with the stranger bonobo instead of the group member.
“The pairs that are unfamiliar with each other are the ones that shared most often,” says JingZhi Tan.
Another study of contagious yawning was run as well. Contagious yawning starts to occur in children when they begin to have empathy towards others. Tan and his team showed videos to the bonobo subjects of other bonobos yawning. When a bonobo saw a video of a stranger yawning, it yawned more often then when it saw a group member yawning.
“It seems that bonobos have a level of emotional engagement or even empathy towards strangers that we don’t see in other species,” says Brian Hare, one of the researchers studying these bonobos.