To prepare for his most recent role as Caesar, the simian revolutionary in Rise of the Planet of the Apes, Serkis studied Oliver, the famous "Human-zee."
Oliver was extraordinary in the sense that he walked bi-pedally. He was brought up by human beings, he was treated very much like a member of the household and looked and behaved and had facial expressions that really, one could imagine, was close to human behavior. He was a touchstone character.Oliver was the subject of an October 2003 feature in The Atlantic, which you can read here.
This article available online at:
http://www.theatlantic.com/entertainment/archive/2011/08/learn-to-behave-like-a-chimpanzee-with-andy-serkis/243124/