Koko was a female western lowland gorilla who was taught to communicate using signs from American Sign Language. She was one of several animals who learned to communicate with human beings in this way. Koko became famous through appearances in many magazines, television programs, and films.
Koko was born July 4, 1971. She became seriously ill as an infant and had to be removed from her group of gorillas at the San Francisco Zoo. When Koko regained her health, the American psychologist Francine Patterson began caring for her and teaching her to sign.
Over the years, Koko learned to make more than several hundred signs. She learned new signs by imitating her teacher’s signs or by having her hands molded to form the sign. Koko also created her own signs. Koko used signs to express what she wanted or felt, to name things, and to ask questions. She also recognized many spoken words of English.
Some scientists questioned the extent of Koko’s language abilities, suggesting that Koko’s teachers read too much meaning into her signs. They argued that Koko could communicate only on the most basic level. Other scientists argued that Koko showed some fairly sophisticated abilities, for example combining the signs for finger and bracelet to make a sign for ring.
Koko often expressed the desire to raise an infant. She had many pets, with whom she was gentle and nurturing. Patterson’s book Koko’s Kitten (1987) tells the story of Koko’s relationship with a tailless cat that she named All Ball. Koko died on June 19, 2018.
