Koko was known for its communication skills and sign language.
Koko, the celebrity Gorilla, died peacefully in its sleep at the age of 46 in California at at Gorilla Foundation's preserve.
Hanabi-Ko was her original name -- meaning "fireworks child" in Japanese. Koko started learning rudimentary sign language with the help of researcher, Dr Francine Patterson. Experts believe that Koko understood about 2,000 English words.
Koko has had an amazing journey. She modeled for National Geographic's cover. Interestingly, Koko clicked that image of herself in a mirror.
Studies on the primate revealed that it had strong maternal instincts and it had adopted a kitten called All Ball. Researcher Patterson filmed Koko asking about the incident. "Cat, cry, have-sorry, Koko-love," replied Koko in its sign language.
Here is a video of Koko playing with her "family".