Koko the Gorilla, Who was Friends with Mr. Rogers and Knew Sign Language, Dies at Age of 46.

The gorilla Koko, who attracted admirers from all over the world with her apparent grasp of sign language, reportedly died in her sleep on Tuesday morning in California, according to the Gorilla Foundation, which oversaw her care. She was 46.

Koko’s early ability in American Sign Language contributed to her rise to stardom. Koko, a western lowland gorilla, gained popularity as he captured the hearts of celebrities over the years, including Fred Rogers and Robin Williams, as well as their followers.

“Koko touched the lives of millions as a champion for all gorillas and an emblem for interspecies dialogue and empathy,” the Gorilla Foundation said in a statement. She was beloved and will be sorely missed.

The New York Times claimed in 1975 that Koko had a vocabulary of more than 170 words by the time she was 4 years old and had the ability to use language imaginatively, according to Penny Patterson, Koko’s lifelong trainer and carer.

Dr. Patterson noted at the time that “she periodically creates new terms [signs] that are wonderfully suited and she is able to tie known phrases together in imaginative and meaningful patterns.” “Koko also enjoys playing word games and is funny.”

Koko was the subject of many films and appeared on the covers of National Geographic in 1978 and 1985 as a result of her multilingualism. The charity claims that by the time of her death, Koko had accumulated a vocabulary of more than 2,000 words.

Koko the gorilla, pictured here on the October 1978 cover of National Geographic, has died at 46. pic.twitter.com/DlHANqVYlE

— National Geographic Magazine (@NatGeoMag) June 21, 2018

After Koko gained notoriety, some scientists began to question the extent of her abilities, arguing that she was only responding to stimuli or that Dr. Patterson and others had inflated her skill by interpreting her actions in a way that fit their own agendas. The debate continued over time, but it had little effect on the declining public interest in Koko.

While in public, she appeared to be joyful, irritated, and saddened. She had always been kind towards animals, and she had a soft spot for cats. She fell in love with a kitten named All Ball, who served as the inspiration for the popular children’s book “Koko’s Kitty.”

Koko wanted a birthday party celebration with her family, which included her cats! pic.twitter.com/r4XFa2gcNy

— Gorilla Foundation (@kokotweets) July 8, 2016

Koko’s fame was also boosted by her relationships with well-known figures like Mr. Rogers, whose television show “Mister Rogers’ Neighborhood” included Koko in one episode in 1998. That appearance was one of the most memorable ones, according to Margy Whitmer, one of the show’s longtime producers.

Koko played with Mr. Rogers’ sweater and told him she liked him since she felt at peace with him right away.

He genuinely showed no anxiety this year, Ms. Whitmer said in an interview with The Times. “He immediately accepted Koko and was extremely peaceful with her.”

Three years later, Koko met Robin Williams, and the two had an instant rapport. In interviews, Mr. Williams complimented the episode, and in a stand-up routine, he even made light of it. In 2014, he passed away, and Koko was reportedly heartbroken.

The Gorilla Foundation states that Koko was born as Hanabi-ko, which is Japanese for “Fireworks Child,” on July 4, 1971, at the San Francisco Zoo. The following year, she began working with Dr. Patterson, who was then a psychology PhD candidate at Stanford University.

Dr. Patterson founded the Gorilla Foundation in 1979, and it was later moved to the Santa Cruz Mountains.

Gorillas in the wild typically live for 30 to 40 years, however those kept in human care have been known to live into their 50s, according to the Smithsonian’s National Zoo and Conservation Biology Institute. In the western hemisphere, lowland gorillas like Koko are an incredibly rare breed.