Koko, The Gorilla Who Mastered Sign Language, Dies At 46

2nd Nat Geo Cover

This was the inspiration behind the second National Geographic cover in January 1985. Koko appeared with her pet kitten All Ball. The photo was taken by Ronald Cohn.

2nd Nat Geo Cover

She Displayed Grief

Unfortunately, in 1984, All Ball escaped from Koko’s cage and was hit by a car. Patterson reported Koko signed “Bad, sad, bad” and “Frown, cry, frown, sad” in response to the event. Patterson also stated Koko made sounds similar to humans when they are crying.

She Displayed Grief