Hanabiko "Koko" (July 4, 1971 – June 19, 2018) was a female Western lowland gorilla, cared for by Penny Paterson. She was known for having learned a large number of hand signs from a modified version of American Sign Language (ASL). Koko was able to understand more than 1,000 signs of what Patterson calls "Gorilla Sign Language" (GSL).
Koko was born at the San Francisco Zoo and lived most of her life in Woodside, California. Koko gained public attention upon initial reportage of her adopting a kitten as a pet.
Koko was also known for meeting many celebrities such as Robin Williams and Mr. Rogers.
Koko died on June 19, 2018 in Woodside, California at the age of 46.