New York: Koko the gorilla, who appeared on National Geographic magazine cover, could chat, tease and even argue with scientists using more than 1,000 hand signs, has died in California at the age of 46.

Koko -- the primary ambassador for her endangered species, who redrew the lines of animal-human communication -- passed away on Tuesday in her sleep, a Gorilla Foundation press release said.

At birth, she was named Hanabi-ko -- Japanese for "fireworks child", because she was born at the San Francisco Zoo on July 4 in 1971. She was a western lowland gorilla.

"Her 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," the Gorilla Foundation said.

Throughout her life, Koko's abilities made headlines. After she began communicating with humans through American Sign Language, she was featured by National Geographic - and she took her own picture (in a mirror) for the magazine's cover.

That cover came out in 1978, seven years after Koko was chosen as an infant to work on a language research project with the psychologist Francine "Penny" Patterson.

In 1985, the magazine profiled the affectionate relationship between the gorilla and her kitten: Koko and All Ball.

Koko, who also apparently understood some spoken English. Instructors taught her a version of American Sign Language and say she used it to convey thoughts and feelings, the BBC reported.

She adopted and named pets, including her kitten, All Ball.

Some scientists have cast doubt on the extent of the gorilla's communicative skills. However, she was the subject of many documentaries.

When her tailless tabby kitten All Ball escaped and was killed by a car in 1984, Dr Patterson wrote that she had displayed grief.

Koko lived most of her life at the Gorilla Foundation in California.
She was filmed meeting the late actor Robin Williams in 2001.

Koko amazed scientists in 2012, when she showed she could learn to play the recorder. The feat revealed mental acuity but also, crucially, that primates can learn to intricately control their breathing - something that had been assumed to be beyond their abilities.