Which great ape learned over 1,000 signs from Francine Patterson?

The great ape that learned over 1,000 signs from Francine Patterson was Koko, a western lowland gorilla. Patterson began teaching Koko sign language in 1972, when Koko was about one year old, and continued working with her for decades.

Koko became famous for using a reported vocabulary of more than 1,000 signs and for understanding roughly 2,000 spoken English words. Her work was part of a long-running interspecies-communication project at the Gorilla Foundation. In the late 1970s, Patterson also published early observations of Koko’s sign production and combinations.

Koko is often confused with Washoe, the chimpanzee associated with American Sign Language research, or Kanzi, the bonobo known for using lexigrams. Koko’s reported language abilities remain controversial because researchers disagree about how reliably her signs demonstrated human-like grammar. Even so, the canonical answer to this trivia question is Koko. She also became widely known for her affection for kittens, including a famous 1983 Christmas story.