Are “Hello” and “Goodbye” Unique to Humans?

People say "hello" and "goodbye" in countless languages and ways, but they aren't alone in those greetings. Researchers believe they have detected similar behavior in bonobos and chimpanzees, who tend to signal when play and grooming sessions begin and end.

Raphaela Heesen, a postdoctoral researcher at Durham University in the United Kingdom, said she became interested when she noticed bonobos repeat a gesture when one of their meetings was interrupted. Her research group studied more than 1,200 interactions and found that bonobos used "hello" and "goodbye" greetings at least 90 percent of the time, and chimps only slightly less often. These brief greetings usually involve eye contact or touch, including head-butting and holding hands.

"Behavior doesn’t fossilize," Heesen said in a statement. "You can’t dig up bones to look at how behavior has evolved. But you can study our closest living relatives: great apes like chimpanzees and bonobos."

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