This is Scientific American's 60-second Science, I'm Mark Stratton."Just imagine it, chatting to a chimp in chimpanzee."Whether portrayed by Rex Harrison, Eddie Murphy or Robert Downey, Jr., Doctor Dolittle learned to talk to animals.But in reality, science has remained some distance from solving the long-standing question of how we humans learned to talk during our evolution.Here's one new clue:a team of researchers in Great Britain have demonstrated how the rapid succession of opening- and closing-mouth rhythms by chimpanzees―known as "lip smacking"―mimics the natural pace of human mouths talking.The findings are in the journal Biology Letters.This phenomenon has been observed before in other ape species who performed lip-smacking movements at around five hertz,which falls within a range of mouth opens and closes characteristic of all spoken languages, namely between two and seven hertz.But this lip-smacking timing connection had not been made in our closest evolutionary relatives―until now."Mouth and vocal signals with speechlike rhythms had already been observed in some monkeys, gibbons and orangutans, one of our closest great ape relatives.So the last years had seen accumulating evidence that these rhythms―other than something that talking humans do―that this was a rhythm from deeper within our primate ancestry, recycled, so to speak, as a cornerstone for speech evolution."
