Somewhat based on Desmond Morris's fascinating book of pop anthropology, this partially animated satirical docudrama produced by Playboy Magazine publisher Hugh Hefner, traces the evolution of human kind and offers insight into the reasons why we behave the way we do. Though often dealing with sexuality, nothing in the film is terribly offensive or graphic. A prime example of mainstream experimental film-making from the early 70's featuring a young and breathtakingly lovely Victoria Principal.