Koko, the gorilla known for her impressive sign language skills, has died. She was 46 years old.
According to a statement released by The Gorilla Foundation, Koko died in her sleep Tuesday.
Koko was born at the San Francisco Zoo in 1971. The next year, she started working with Francine "Penny" Patterson, who began teaching her sign language.
The foundation says it will continue its work to conserve and preserve gorillas.
Additional reporting from Newsy affiliate CNN.
