Editor's note: Koko the gorilla, an ambassador for her species famous for learning sign language, has died at the age of 46. To honor Koko's memory, National Geographic is republishing "Conversations With a Gorilla," our October 1978 cover story written by Francine Patterson, the psychologist who taught Koko how to sign.
Current research paints a more complicated picture of primate sign language than was understood in the 1970s. We are presenting this article as originally published; the science within may not be up-to-date.
Koko is a 7-year-old “talking” gorilla. She is the focus of my career as a developmental psychologist, and also has become a dear friend.