Scientists believe the lip smacks of chimps confirm human speech has "ancient roots within primate communication". Chimpanzees smack their lips in a rhythm similar to human speech - which could solve the mystery of how speech evolved, a new study has found.

Why do monkeys slap their lips?

Often, a monkey will lip smack to a more dominant monkey as a sign of submission. You might also see monkeys lip smacking to one another after having a disagreement as a way of apologizing and making sure all is forgiven. It can also be a sign of affection or contentment.

What does it mean when monkeys chatter?

Teeth chattering is seen in many primate species and has been proposed to have a range of social functions. ... Using these data, we tested the predictions of four hypotheses: teeth chattering functions as a signal of submission, appeasement, affiliation or reassurance. Support was found for all four hypotheses.