Koko (born July 4, 1971) is a female gorilla who, according to Francine “Penny” Patterson, her long-term trainer, is able to understand more than 1,000 signs based on American Sign Language, and understand approximately 2,000 words of spoken English.
As with other ape language experiments, the degree to which Koko masters these signs has been controversial, as has been the degree to which such mastery demonstrates language abilities.
Koko was born at San Francisco Zoo and has lived most of her life in Woodside, California, although a move to a sanctuary on Maui, Hawaii, has been planned since the 1990s. Koko is short for the name Hanabiko (花火子 literally “fireworks child”?) in Japanese, a reference to her date of birth, the Fourth of July.