Laughter has been a part of our genetic heritage for a very, very long time, but modern great apes certainly do not use it in nearly as many contexts or with nearly the same frequency as we do. How does the mutual vulnerability theory explain the substantial expansion in its use since our split from the chimpanzee/bonobo lineage approximately 6 million years ago? Great apes use laughter in a manner comparable to that of human infants and toddlers, mostly in association with tickling and physical play, but we must note these constitute the active and intentional altering of the status relationships among their participants. Thus, they are not simply engaging in laughter, but in acts of humor as well. Apes in sign language studies have participated in simple games and pranks, used words in absurd statements, and developed novel forms of insult. Still, the lives of modern human are much more complex cognitively and socially, with new forms of vulnerability being highlighted in ways apes simply cannot fathom. Our “play” has increased in its scope and frequency by orders of magnitude, and we can project the consequences of various types of shortcomings and assets far into the future.