Vertical![]() Two young bonobos exhibit the ape equivalent of the human laugh, a “play face,” which is accompanied by laugh-like panting sounds. Just as in humans, if one ape laughs others usually do as well, especially during wrestling and tickling games. Frans de Waal | Horizontal![]() Two young bonobos exhibit the ape equivalent of the human laugh, a “play face,” which is accompanied by laugh-like panting sounds. Just as in humans, if one ape laughs others usually do as well, especially during wrestling and tickling games. Frans de Waal | ThumbTwo young bonobos exhibit the ape equivalent of the human laugh, a “play face,” which is accompanied by laugh-like panting sounds. Just as in humans, if one ape laughs others usually do as well, especially during wrestling and tickling games. Frans de Waal |