(CNN) - Koko, the gorilla who mastered sign language and showed the world what great apes can do, has died.
She died Tuesday in her sleep at age 46, The Gorilla Foundation said in a statement.
"Koko touched the lives of millions as an ambassador for all gorillas and an icon for interspecies communication and empathy," the release said. "She was beloved and will be deeply missed."
She learned to communicate at a young age
The western lowland gorilla was born at the San Francisco Zoo in 1971 and began to learn sign language early in life. S
Researchers moved her to Stanford in 1974 and established The Gorilla Foundation, a non-profit organization that works to preserve and protect gorillas.
Koko and The Gorilla Foundation later moved to the Santa Cruz Mountains.
She liked to read and be read to, a blog post by The Gorilla Foundation said. She purred at parts of books she particularly enjoyed.
She was very maternal toward kittens, and has had several throughout her lifetime. Her "tenderness" showed people how loving a gorilla can be, the foundation said.
Koko made famous friends like Fred Rogers, who appeared on TV as Mr. Rogers, and Robin Williams. She used her sign language skills to communicate with them.
She was said to have understood some 2,000 words of spoken English, and could usually keep up with conversations.
She taught the world about gorillas
The foundation says she has taught the world a profound amount about the emotional capacity and cognitive abilities of gorillas.
Koko appeared in several documentaries and twice on the cover of National Geographic. The first cover featured a photo she'd taken of herself in a mirror, the foundation said.
She was widely promoted through appearances and the release of a picture book about her and a kitten that lived with her.
She has also been exhibited as a painter.
The foundation will continue its work on conservation and preservation of gorillas with continued projects, including a sign language application featuring Koko.
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