Koko, a western lowland gorilla who became internationally famous for learning to communicate in sign language, has died at the age of 46.
The Gorilla Foundation announced Koko’s death, saying she would be “deeply missed”.
“Koko touched the lives of millions as an ambassador for all gorillas and an icon for interspecies communication and empathy,” the foundation said in a statement.
Koko was born Hanabi-ko (Japanese for “Fireworks Child”) on July 4, 1971 at the San Francisco Zoo. When she was about 12 months old, Stanford University student Francine “Penny” Patterson started to train her to use sign language.
Her handler claimed she learned to understand and use more than 1,000 different signs, although some scientists questioned the claim.
Koko was among a handful of primates who could communicate using sign language; others included Washoe, a female chimpanzee in Washington state, and Chantek, a male orangutan in Atlanta. Her keepers said she understood some spoken English, too.
In 1983, Koko famously asked for a cat — a wish that was eventually granted. For her birthday in 1985, researchers brought her a litter of kittens and let her choose one to keep.
The primate selected a grey and white kitten, who she named “All Ball”, supposedly because the animal looked like a ball and Koko enjoyed words that rhymed. The ape nurtured All Ball like it was her offspring and even tried to nurse it at one point.
Koko was reportedly upset for days after All Ball was killed by a car, Ron Cohn, a biologist with the Gorilla foundation told the Los Angeles Times in 1985.
“She started whimpering — a distinct hooting sound that gorillas make when they are sad. We all started crying together,” he said.
Koko went on to have many cat companions and Ms Patterson wrote a children’s book in 1990 called Koko’s Kitten, which told of the gorilla’s love of her feline companion.
The gorilla was featured in many documentaries and appeared on the cover of National Geographic magazine twice. The front of the October 1978 issue featured a photograph Koko had taken of herself in a mirror.
In 1998, Koko took to the Internet in what was billed as the first “interspecies” chat, relaying comments such as “I like drinks” via a human interpreter to tens of thousands of online participants.
She famously met actor Robin Williams in 2016 and the two struck up a friendship, laughing and playing together. Koko heard about Mr Williams’s death in 2016 and became “extremely sad”, signing the word “cry” and bowing her head, according to a blog on the Gorilla Foundation website.
Announcing Koko’s death on Thursday, the organisation said it “will continue to honour Koko’s legacy with ongoing projects including conservation efforts in Africa, the great ape sanctuary on Maui, and a sign language application featuring Koko for the benefit of both gorillas and children”.
Additional reporting by Reuters
