The gorilla, who formed friendships with celebrities such as Robin Williams, died peacefully in her sleep in California

This article is more than 2 years old

This article is more than 2 years old

Koko, the gorilla that learned sign language and formed several celebrity friendships while in captivity in the US, has died aged 46.

The female western lowland gorilla, who gained fame for her mastery of “gorilla sign language”, died peacefully in her sleep at the Gorilla Foundation’s preserve in California, the foundation said.

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Originally named Hanabi-ko – Japanese for “fireworks child” – after being born at San Francisco Zoo in 1971, Koko learned a rudimentary sign language through a researcher, Dr Francine Patterson. Koko reportedly understood about 2,000 words of verbal English.

The subject of numerous documentaries, Koko also appeared on the cover of National Geographic, in a picture that the primate took of herself in a mirror. Koko adopted a kitten called All Ball and when the feline was hit and killed by a car in 1984, Patterson was filmed asking Koko what had happened. Koko signed in response: “Cat, cry, have-sorry, Koko-love.”

Further anguish was to come for Koko following the death in 2014 of the actor and comedian Robin Williams. Koko and Williams had struck up a firm friendship in 2001, with the two filmed laughing and cuddling together. The Gorilla Foundation said that Patterson told them Koko was “quiet and very thoughtful” when told of Williams’s passing.

Koko also met Flea, the bassist in the Red Hot Chili Peppers, and the actor Betty White. The gorilla also surprised scientists in 2012 by demonstrating an ability to play the recorder. A treat for one birthday was a box of kittens to play with.

“Her impact has been profound and what she has taught us about the emotional capacity of gorillas and their cognitive abilities will continue to shape the world,” the Gorilla Foundation said.