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

FILE-- Koko the gorilla and her kitten. Koko died at the age of 46 in her sleep. FILE-- Koko the gorilla and her kitten. Koko died at the age of 46 in her sleep. Photo: Ron Cohn Photo: Ron Cohn Image 1 of / 72 Caption Close Koko, the beloved gorilla who knew sign language, dies at age 46 1 / 72 Back to Gallery

Koko, the beloved gorilla who shocked the world with her mastery of sign language and ability to communicate with humans, died in her sleep at the age of 46, officials announced Thursday.

The western lowland gorilla, born on July 4, 1971 at the San Francisco Zoo, spent the bulk of her extraordinary life at the Gorilla Foundation in Woodside. Her full name, Hanabi-ko, is Japanese for “Fireworks Child.”

When Koko was just a year old, her doctor, Francine “Penny” Patterson, decided to teach her a few basic signs including, food, drink and more. Patterson would speak the words as she signed them, according to the Gorilla Foundation.

In just three years, Koko learned more than 200 new signs and eventually her vocabulary exceeded 1100 signs. Patterson would also speak the words, which helped Koko learn 2,000-plus words in English.

“Koko touched the lives of millions as an ambassador for all gorillas and an icon for inter-species communication and empathy,” the foundation said in a statement. “She was beloved and will be deeply missed.”

Koko was featured in numerous documentaries for her talents. Most recently, the ape was the focus of a Netflix documentary based on her relationship with Patterson called “Koko: The Gorilla Who Talks.”

Her celebrity brought her friends from around the world, including the late Robin Williams. The pair met in 2001.

“We shared something extraordinary: laughter,” Williams said of his encounter with Koko in a YouTube video.

“It was awesome and unforgettable,” he added.

Her other friends included Betty White and Mr. Rogers.

Koko was twice featured on the cover of National Geographic. Her first magazine cover was in October 1978, featuring a photograph that Koko took of herself in the mirror. The second cover in January 1985 focused on a story of Koko with her beloved pet cat, All Ball.

“The reason that it stands out in people’s memories is because there’s an emotional surprise there,” Patterson said in a video. “There’s a giant gorilla with a tiny, tiny, tiny, helpless kitten and being gentle and loving towards that kitten.”

Koko named the kitten All Ball because it looked like a ball to her, according to the Gorilla Foundation.

When All Ball died, Koko mourned the cat’s death. Children’s books focusing on Koko’s relationship with her kitty were published and used in elementary schools worldwide, the foundation said.

The foundation was started in 1974 at Stanford University by Patterson and Dr. Ronald Cohn to teach sign language to gorillas — though not without some criticism from other experts. In 1976, the foundation moved to the Santa Cruz Mountains.

“[Koko’s] 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 foundation said.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani