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. She used many signs adapted from American Sign Language, and understood nouns, verbs, and adjectives, including abstract concepts such as "good" and "false", scoring between 70 and 90 on various IQ scales, with some experts, including Mary Lee Jensvold, stating that Koko "used language in the same way as people". However, the scientific consensus is that she did not demonstrate the syntax or grammar required of true language. Meanwhile, Patterson herself has been widely criticized for misrepresenting Koko's skills, providing insufficient care for Koko and her companion gorillas, and treating Gorilla Foundation staff members inappropriately.

Koko's story helped to change the public image of gorillas, previously assumed to be brainless and violent. After Koko's death, the journal Science published an obituary noting that she had "helped transform how the human world viewed animal emotion—and intelligence".