Humans and apes both like a laugh and their giggles may have a common origin, scientists say.
Human laughter has a long ancestry and it can be traced back between 10 million and 16 million years, when humans and great apes shared a common ancestor, the researchers said.
Marina Davila Ross, from the University of Portsmouth, tickled the palms, feet, necks and armpits of 22 young apes from four species, as well as three human babies, to build up a library of 800 acoustic recordings of laughter that she was able to analyse scientifically for their similarities and differences.
"Our results on laughter indicate its pre-human basis. It is likely that great apes use laughter sounds to interact in similar ways to humans," Dr Ross said.
The study found that the similarities and the differences in patterns of laughter sounds in orangutans, gorillas, chimpanzees, bonobos and humans corresponded closely to the genetic relatedness of the species, indicating that laughter in both apes and humans had a common origin in a shared ancestor.