Koko, a beloved gorilla that learned to communicate with humans and then stole their hearts, has died.

The Gorilla Foundation said the 46-year-old celebrity ape — a western lowland gorilla — died in her sleep earlier this week at the organization’s preserve in Northern California. The Gorilla Foundation, a nonprofit organization that works to study and protect great apes, said in a statement that Koko will be most remembered “as the primary ambassador for her endangered species.”

“Koko touched the lives of millions as an ambassador for all gorillas and an icon for interspecies communication and empathy,” the statement said. “She was beloved and will be deeply missed.”
“Koko’s capacity for language and empathy has opened the minds and hearts of millions,” the statement read. “She has been featured in multiple documentaries and appeared on the cover of National Geographic twice. The first cover, in October of 1978, featured a photograph Koko had taken of herself in a mirror. The second issue, in January of 1985, included the story of Koko and her kitten, All Ball. Following the article, the book Koko’s Kitten was published and continues to be used in elementary schools worldwide.

“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.”