The discovery, published in the journal Current Biology, could help explain how humans evolved to take turns before speaking.
Marmosets are a friendly and peaceful species of monkey that help one another raise their young.
Princeton University’s Asif Ghazanfar found that the small primates will carry on vocalizations even with relative strangers, following a set of unspoken rules of conversation etiquette.
He discovered they don’t call at the same time, but instead wait for about 5 seconds after another has finished “talking” before responding.
This behavior differs greatly from chimps and other great apes, which don’t vocalize much at all and don’t take turns when they do.
“This makes what we found (in marmosets) much more similar to human conversations and very different from the coordinated calling of animals such as birds, frogs or crickets, which is linked to mating or territorial defense,” said Ghazanfar.
He believes the monkeys may find the pattern of conversation relaxing.
“We are currently exploring how very early life experiences in marmosets — including those in the womb and through to parent-infant vocal interactions — can illuminate what goes awry in human communication disorders,” Ghazanfar said.
Other types of monkeys, including tamarins, may also hold polite conversations.