Desmond Morris is regularly referred by top character animator for his zoology studies applied to the human: “Manwatching” as he called his 1977 book.

He wrote few book but as a start you could already check his first video from a series of 6 called “the language of the body”. Consider yourself lucky I think they are all available on Google video.

The first one is probably the most interesting as he quickly goes through a classification of gestures.

If you want to know more about the man. Check that fascinating 58 minutes video about his life.