Koko

**Hanabiko** "**Koko**" (July 4, 1971 – June 19, 2018) was a female western lowland gorilla. Koko was born at the San Francisco Zoo and lived most of her life in Woodside, California, at The Gorilla Foundation's preserve in the Santa Cruz Mountains. The name "Hanabiko" (花火子), lit. ''fireworks child'', is of Japanese origin and is a reference to her date of birth, the Fourth of July. Koko gained public attention upon a report of her having adopted a kitten as a pet and naming him "All Ball", revealing her ability to rhyme.

Her instructor and caregiver, Francine Patterson, reported that Koko had an active vocabulary of more than 1,000 signs of what Patterson calls "Gorilla Sign Language" (GSL). This puts Koko's vocabulary at the same level as a three-year-old human. In contrast to other experiments attempting to teach sign language to non-human primates, Patterson simultaneously exposed Koko to spoken English from an early age. It was reported that Koko understood approximately 2,000 words of spoken English, in addition to the signs. Koko's life and learning process has been described by Patterson and various collaborators in books, peer-reviewed scientific articles, and on a website.

As with other great-ape language experiments, the extent to which Koko mastered and demonstrated language through the use of these signs is debated. She certainly understood nouns, verbs, and adjectives, including abstract concepts like "good" and "fake", and was able to ask simple questions. It is generally accepted that she did not use syntax or grammar, and that her use of language did not exceed that of a young human child. However, she scored between 70 and 90 on various IQ scales, and some experts, including Mary Lee Jensvold, claim that Koko "[used] language the same way people do".

## Early life and popularity

Koko was born on July 4, 1971, at the San Francisco Zoo to her biological mother Jacqueline and father Bwana. Koko was the 50th gorilla born in captivity and one of the first gorillas accepted by her mother in captivity. Koko remained with her mother until the age of one when Koko was taken to the zoo's hospital to be treated for a life-threatening illness. Patterson along with Charles Pasternak originally cared for Koko at the San Francisco Zoo as part of their doctoral research at Stanford University after Koko came to the zoo's hospital. Koko was loaned to Patterson and Pasternak under the condition that they would spend at least four years with her. Eventually, Koko remained with Patterson, supported by The Gorilla Foundation, which Patterson founded to support gorilla research and conservation.

In 1978, Koko gained worldwide attention as she was pictured on the cover of *National Geographic* magazine. The cover picture was an image of Koko taking her own picture in the mirror. Koko was later featured on the cover of National Geographic in 1985 with a picture of her and her kitten, All Ball. At the preserve, Koko also met and interacted with a variety of celebrities including Robin Williams, Fred Rogers, Betty White, William Shatner, Flea, Leonardo DiCaprio, Peter Gabriel, and Sting.

## Characteristics

### Use of language

Patterson reported that Koko's use of signs indicated that she mastered the use of sign language. Koko's training began at the age of 1 and she had a working vocabulary of more than 1,000 signs, which she was able to combine in complex ways. Despite her dexterity and literacy, she was never taught how to write.

Patterson reported that Koko made several complex uses of signs that suggested a more developed degree of cognition than is usually attributed to non-human primates and their use of communication. For example, Koko was reported to use displacement (the ability to communicate about objects that are not currently present). At age 19, Koko was able to pass the mirror test of self-recognition, which most other gorillas fail. She had been reported to relay personal memories. Koko was reported to use meta-language, being able to use language reflexively to speak about language itself, signing "good sign" to another gorilla who successfully used signing. Koko was reported to use language deceptively, and to use counterfactual statements for humorous effects, suggesting an underlying theory of other minds.

Patterson reported that she documented Koko inventing new signs to communicate novel thoughts. For example, she said that nobody taught Koko the word for "ring", but to refer to it, Koko combined the words "finger" and "bracelet", hence "finger-bracelet".

Criticism from some scientists centered on the fact that while publications often appeared in the popular press about Koko, scientific publications with substantial data were fewer in number. Other researchers argued that Koko did not understand the meaning behind what she was doing and learned to complete the signs simply because the researchers rewarded her for doing so (indicating that her actions were the product of operant conditioning). Another concern that has been raised about Koko's ability to express coherent thoughts through signs is that interpretation of the gorilla's conversation was left to the handler, who may have seen improbable concatenations of signs as meaningful. For example, when Koko signed "sad" there was no way to tell whether she meant it with the connotation of "How sad". Following Patterson's initial publications in 1978, a series of critical evaluations of her reports of signing behavior in great apes argued that video evidence suggested that Koko was simply being prompted by her trainers' unconscious cues to display specific signs, in what is commonly called the Clever Hans effect.

### Intelligence

Between 1972 and 1977, Koko was administered several infant IQ tests, including the Cattell Infant Intelligence Scale and form B of the Peabody Picture Vocabulary Test. She achieved scores in the 70–90 range, which is comparable to a human infant that is slow but not intellectually impaired. According to Francine Patterson, however, it is specious to compare her IQ directly with that of a human infant because gorillas develop locomotor abilities earlier than humans and many IQ tests for infants require mostly motor responses. Gorillas and humans also mature at different rates, so using a gorilla's chronological age to compute their IQ results in a score that is not very useful for comparative purposes.

### Pets

Researchers at The Gorilla Foundation said that Koko asked for a cat for Christmas in 1983. Ron Cohn, a biologist with the foundation, explained to the *Los Angeles Times* that when she was given a lifelike stuffed animal, she was less than satisfied. She did not play with it and continued to sign "sad". So on her birthday in July 1984, she was able to choose a kitten from a litter of abandoned kittens. Koko selected a gray male Manx and named him "All Ball". Penny Patterson, who had custody of Koko and who had organized The Gorilla Foundation, wrote that Koko cared for the kitten as if it were a baby gorilla. Researchers said that she tried to nurse All Ball and was very gentle and loving. They believed that Koko's nurturing of the kitten and the skills she gained through playing with dolls would be helpful in Koko's learning how to nurture an offspring.

In December 1984, All Ball escaped from Koko's cage and was hit and killed by a car. Later, Patterson said that when she signed to Koko that All Ball had been killed, Koko signed "Bad, sad, bad" and "Frown, cry, frown, sad, trouble". Patterson also reported later hearing Koko making a sound similar to human weeping.

In 1985, Koko was allowed to pick out two new kittens from a litter to be her companions. The animals she chose, which she named "Lips" and "Smoky", were also Manxes. Koko picked the name after seeing the tiny orange Manx for the first time. When her trainer asked the meaning of the name, Koko answered, *Lips lipstick*.

The Gorilla Foundation also briefly played home to a male green-winged macaw of mysterious origin who had been found inhabiting the grounds and feeding on the loquat trees, though he was not a pet of Koko's in the same way her cats were. Initially frightened of the parrot, Koko named him "Devil Tooth", "devil" presumably coming from his being mostly red, and "tooth" for his fierce-looking white beak; the human staff adjusted the name to "Devil Beak", and ultimately to "DB".

To celebrate her birthday in July 2015, Koko was presented another litter of kittens. Picking two, she named them Miss Black and Miss Grey.

## Later life and death

After Patterson's research with Koko was completed, the gorilla moved to a reserve in Woodside, California. At the reserve, Koko lived with another gorilla, Michael, who also learned sign language, but he died in 2000. She then lived with another male gorilla, Ndume, until her death. Koko's weight of 280 pounds (127 kg) was higher than would be normal for a gorilla in the wild, where the average weight is approximately 150–200 pounds (70–90 kg), but the foundation stated that Koko "is, like her mother, a larger frame Gorilla".

Koko died in her sleep during the morning of June 19, 2018, at the Gorilla Foundation's preserve in Woodside, California, at the age of 46. The Gorilla Foundation released a statement that "The impact has been profound and what she has taught us about the emotional capacity of gorillas and their cognitive abilities will continue to shape the world." Even though Koko was 46 years old when she died, her death took staff members of the Gorilla Foundation by surprise.