Koko (gorilla)

Hanabiko, nicknamed "Koko" (July 4, 1971 – June 19, 2018) was a female western lowland gorilla born in the San Francisco Zoo and cross-fostered by Francine Patterson for use in ape language experiments. Koko gained public attention as the subject of two National Geographic cover stories and, in 1985, the best-selling children's picture book, Koko's Kitten. Koko became the world's most famous representative of her critically endangered species.

Koko's communication skills were hotly debated. Koko used many signs adapted from American Sign Language, but the scientific consensus to date remains that she did not demonstrate the syntax or grammar required of true language. Patterson has been widely criticized for misrepresenting Koko's skills, providing insufficient care for Koko and her companion gorillas, and inappropriate treatment of Gorilla Foundation staff members.

Despite such controversies, Koko's story helped to change the public image of gorillas, previously said by some to be brainless and violent. After Koko's death, the journal Science published an obituary noting that Koko has "helped transform how the human world viewed animal emotion—and intelligence."