Bonobos and Chimps Appear to Have 'Hello' and 'Goodbye' Greetings
Like humans, these apes share salutations to start and end interactions
Before engaging in social behaviors like grooming, bonobos (pictured) employed a "hello" greeting during 90 percent of observed interactions and bid their peers farewell 92 percent of the time. (NauticalVoyager via Pixabay )
By Corryn Wetzel
SMITHSONIANMAG.COM
AUGUST 12, 2021
Humans rely on a simple wave, smile, or phrase to politely acknowledge the beginning and end of an interaction. New research reveals that chimpanzees and bonobos employ similar social manners: the great apes start and end grooming and play sessions with actions akin to a human “hello” and “goodbye.”
The study published yesterday in the journal iScience is the first to show this behavior in a non-human species and sheds new light on the evolution of cooperation and social commitment in great apes.
“We were able to launch rockets and land on the moon because we have the ability to share our intentions, which allows us to achieve things so much bigger than a single individual can achieve alone,” says Raphaela Heesen, a postdoctoral researcher at Durham University in the United Kingdom, in a statement.
Scientists have long known that chimps and bonobos are socially complex creatures, but Heesen’s curiosity about their interactions was sparked after witnessing two bonobos repeat a gesture after the grooming session was interrupted, according to a statement. She wondered if they share a social custom similar to human salutations.
More:
https://www.smithsonianmag.com/smart-news/bonobos-and-chimps-appear-have-hello-and-goodbye-greetings-180978428/
= new reply since forum marked as read
At least, that is what my many years of study have indicated. 
Seriously, though, I love the studies that show how we creatures have more similarities than people realized.
But now that you mention it, one of mine does stretch before she head bumps. I never realized what she was saying!
Another asks for affection by bumping his head against my ankles, then flopping on my feet. 
