The BBC wrote:Wild bonobos use a single high-pitched call in a variety of contexts, showing a flexibility in their communication that was thought to be uniquely human.
That is the conclusion of a study by UK and Swiss psychologists.
Bonobos are just as closely related to humans as chimpanzees, but their wild communication is much less studied.
Researchers say the new findings push back the development of context-free vocal calls to our shared ancestor with bonobos, 6-10 million years ago.
For a long time, it was assumed that non-human primates, including great apes like chimpanzees and bonobos, could only communicate using calls that were tied to specific emotional states - such as screaming in alarm, or barking for aggression.
Using a single vocal signal in multiple contexts - referred to as "functional flexibility" - was thought to be a human ability. And it is something we develop very early.
Babies as young as 3-4 months, for example, have been shown to use squeals and growls across a wide range of situations, whether they are happy, distressed or neutral. These sit alongside other noises that are obviously tied to particular emotions, such as crying and laughing.
Dr Zanna Clay from the University of Birmingham noticed a similar phenomenon among the bonobos she was studying in the Democratic Republic of Congo.
As well as the usual screams, barks, pants and grunts, she heard a particular squeaking sound or "peep" being used all over the place.
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