By Richard Alleyne, Science Correspondent
Published: 7:00AM BST 05 Jun 2009
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Researchers who carried out "tickling sessions" on gorillas, chimpanzees and orangutans, believe that it started out as a "grunt-like" noise with our distant ancestors and gradually turned into the more sophisticated chuckles and guffaws we know today.
They made the assertions published in the journal of Current Biology after finding that the evolution of laughter almost exactly mirrors genetic evolution.
Our closest relatives, the chimp and the bonobo, have the closest laugh to ours, with more distant cousins - gorillas and orangutans - less similar.
Dr Marina Davila Ross said the research seemed to prove not only that great apes do laugh like us but that the act itself was "hardwired into humans" by a distant ancestor.
"Our results on laughter indicate its prehuman basis," she said. "It is likely that great apes use laughter sounds to interact in similar ways to humans.
"This is important for emotional research in humans and animals as well as for the management of primates in captivity and in the wild."
Dr Davila Ross and her team at the University of Portsmouth took more than 800 acoustic recordings from 22 juvenile and infant apes and three human babies while their palms, feet, necks and armpits were being tickled.
They then compared the sounds and discovered links between the two – as well as the evolutionary trail from the most primitive apes to humans.
The study proves that laughter evolved gradually over the last 10 to 16 million years of primate evolutionary history, the researchers said.
Human laughter is nonetheless clearly distinct from the laughter of great apes because evolutionary changes have been more rapid in the last 5 million years, it said.