Koko, gorilla who learned sign language, dead at 46

SAN FRANCISCO — Koko the gorilla, whose remarkable sign-language ability and motherly attachment to pet cats helped change the world’s views about the intelligence of animals and their capacity for empathy, has died at 46.

Koko was taught sign language from an early age as a scientific test subject and eventually learned more than 1,000 words, a vocabulary similar to that of a human toddler.

She became a celebrity who played with the likes of William Shatner, Sting, Leonardo DiCaprio, Robin Williams and Mr. Rogers. At her home preserve, where she was treated like a queen, she ran around with Williams’ eyeglasses and unzipped Rogers’ famous cardigan sweater.

In so doing, Koko showed the American public that a giant ape didn’t have to be scary but wanted to be tickled and hugged.

The Gorilla Foundation said the 280-pound western lowland gorilla died in her sleep at the foundation’s preserve in California’s Santa Cruz mountains Tuesday.

Koko was the not the first animal to learn sign language and communicate, but through books and media appearances she became the most famous. Yet there was debate in the scientific community about how deep and human-like her conversations were.

Koko appeared in many documentaries, including a 2015 PBS one, and twice in National Geographic.

“Koko the individual was supersmart, like all the apes, and also sensitive, something not everyone expected from a ‘king kong’ type animal that movies depict as dangerous and formidable,” Emory University primate researcher Frans de Waal said in an email Thursday.