Oo oo, ha ha: why humans and great apes giggle alike when tickled

Oo oo, ha ha: why humans and great apes giggle alike when tickled Nature Rhythm and timing in laughter reveal that human vocal plasticity falls on a hominid continuum | Communications Biology Nature To Reveal the Rhythmic Roots of Laughter, Just Tickle an Ape The New York Times Scientists Tickled Gorillas And Found A 15-Million-Year-Old Clue To How Humans Learned Speech Forbes Apes and humans have been sharing a laugh for 15 million years Phys.org