ZUM4885364: Feb. 24, 2012 - A most incredible relationship: The most incredible relationship between man and beast in the United States, if not the world, is the friendship between animal psychologist Francine 'Penny' Patterson and 'Koko', a highly intelligent gorilla. The pair work together continuously in the primate education department of Stanford University in California. Penny has succeeded in teaching the gorilla a vocabulary of over 200 words. This she has done through a series of signs used the deaf and dumb language. She is seen here with 'Koko' on the University grounds during a break between lessons / Bridgeman Images