Koko, the gorilla who knew sign language, dies at 46

This image from the National Geographic Society is of Francine 'Penny' Patterson showing a banana to Koko, a 130 pound lowland Gorilla. Koko spent six years training to become the first of her species to attain proficiency in sign language. With an auditory keyboard linked to a computer Koko was able to produce spoken words as well as signs.

The Gorilla Foundation said that the 46-year-old western lowland gorilla named Koko died in its sleep at the foundation’s preserve in California’s Sana Cruz mountains on Tuesday.

Koko was born at the San Francisco Zoo, and Dr. Francine Patterson began teaching the gorilla sign language that became part of a Stanford University project in 1974.

The foundation says Koko’s capacity for language and empathy opened the minds and hearts of millions.

Koko appeared in many documentaries and twice in National Geographic. The gorilla’s 1978 cover featured a photo that the animal had taken of itself in a mirror.

The foundation says it will honor Koko’s legacy with a sign language application featuring Koko for the benefit of gorillas and children, as well as other projects.