The primary program of The
Gorilla Foundation/Koko.org involves teaching American Sign Language
to two lowland gorillas, Koko and Michael
(who recently passed away). The Gorilla Language Project, or Project
Koko, is the longest continuous inter-species communications project
of its kind in the world, and it serves as a unique and irreplaceable
resource for the international conservation community.
Studying gorilla intelligence and behavior will lead to a greater
understanding of the species' physical and psychological needs. Only
through knowledge can humans take the necessary steps to improve the
treatment of captive gorillas and protect free-living gorillas from
Koko, a female lowland gorilla born in 1971, and Michael,
a male lowland gorilla born in 1973, use sign language and understand
spoken English. Koko's participation in this study began when she
was one year old, and Michael's at the
age of three and one-half. Their intellectual, physical, and linguistic
development has been studied extensively since their infancy. Before
Project Koko, very little was known about gorilla intelligence.
The Gorilla Language Project is both an effort to gather data about
gorilla language and a case study of observed gorilla behavior and
utterances. All signs, the context in which they occurred, the number
of repetitions, and anything unusual that might have occurred during
signing are recorded daily. The project administers informal and formal
tests of vocabulary comprehension and of the understanding of relationships
between objects and words, as well as standard child intelligence
tests. There are also periodic video-taped sessions and audio-taped
During the course of the study, Koko has advanced further with language
than any other non-human. Koko has a working vocabulary of over 1000
signs. Koko understands approximately 2,000 words of spoken English.
Koko initiates the majority of conversations with her human companions
and typically constructs statements averaging three to six words.
Koko has a tested IQ of between 70 and 95 on a human scale, where
100 is considered "normal." Michael, the
male silverback gorilla who grew up with Koko, had a working vocabulary
of over 600 signs.
In addition to intensive studies of vocabulary acquisition, the project
has investigated spontaneous gorilla language use. This involves the
study of innovative linguistic strategies, invention of new signs
and compound words, simultaneous signing, self-directed signing, displacement,
prevarication, reference to time and emotional states, gestural modulation,
metaphorical word use, humor, definition, argument, insult, threat,
fantasy play, storytelling and moral judgment. The depth and variety
of gorilla language use has significantly exceeded initial expectations.
Indeed, evidence has been found for the existence, in less developed
form, of almost every aspect of human behavior.
Project Koko is the cornerstone of TGF/Koko.org's work. By demonstrating
the intelligence of gorillas, TGF/Koko.org can more effectively lobby
for the humane treatment of captive animals and increased conservation
efforts for those that are free-living. Project Koko has proven the
stereotyped image of gorillas as blood-thirsty, destructive monsters
unequivocally false. Indeed, it has forced a re-examination of traditional
thought regarding all animals. The project has shown that an animal
can possess qualities that were previously considered exclusively
human, such as thought processes, imagination and feelings. This knowledge
is crucial to all animal advocacy efforts, from the prevention of
cruelty to animals to the conservation and preservation of endangered
The study of gorilla language acquisition sheds light on the vital
connection between gorillas and their sibling species, homo sapiens.
Project Koko has contributed to the study of the evolution and development
of human communication and suggests a gestural origin of human language.