Monkey See, Monkey Hee

Photo: ianduffy/Flickr

Talk about a fun job: Primatologist and psychologist Marina Davila Ross led a team that tickled infant and juvenile apes as well as human babies, recording more than 800 laughs. (Can't you just hear it now? "Sorry honey, I just had a long day tickling baby chimps.") This certifiably adorable study found that all great apes – gorillas, chimpanzees, bonobos, and orangutans – laugh.

It was previously thought that chimps' chuckles were too different from humans' (exhaling and inhaling vs. humans' exhale-only laugh) to count as true laughter. The tickle study, however, found evidence that gorilla giggles share key traits with human laughter – their exhaling breaths during laughter lasted three to four times longer than during normal breathing. And primatologist Frans de Waal pointed out that primate laugh occurs in playful contexts, further underlining its similarity to the human laugh.

While Aristotle theorized that laughter is what separates humans from animals, it seems that our laughter has simply evolved along with us. Evolution explains the differences between human and ape laughter. Now the only question left is: do apes fake-laugh at their in-laws' lame jokes?

Tags: apes, chimpanzee, monkey