Chimpanzees and bonobos greet each other and also signal their goodbyes, according to a new scientific study. The animals, the researchers write, "will orient their bodies toward each other, gaze at each other and display the intention to touch, hug or kiss each other even before they start talking." From CNN:
Scientists say the apes' ability to signal hellos and goodbyes indicates something much bigger than politeness. It shows that chimpanzees and bonobos can communicate a mutual sense of obligation towards each other.
"In humans, that (sense of mutual obligation) bears witness of joint commitments," said the study's lead author Raphaela Heesen, a postdoctoral researcher at Durham University in the United Kingdom. "That underpins all kinds of joint interactions, including small scale ones — for example, you having lunch with your friends, or large scale ones, like big projects."…
The power dynamics and familiarity between two primates also played a role in how much of a "hello" or "goodbye" the animals offered up.
"When they were iterating with a good friend, they produced shorter entry and exit phases … and they often didn't even communicate at the end of an interaction," Heesen added. "And we know that from our daily lives too, right? If we're interacting with a good friend, we don't have that kind of politeness."
"Assessing joint commitment as a process in great apes" (iScience)