Video: Koko the Gorilla's Most Incredible Moments, From Sign Language to Playing With Kittens

Koko the gorilla, who has died at the age of 46, was famed for her communication skills and her mastery of sign language. Taught by animal psychologist Francine "Penny" Patterson and others since the early 1970s, Koko was learning to sign at the tender age of one.

The video below shows Patterson teaching Koko to sign the basic words "eat," "drink" and "more" back in 1972. Her vocabulary would expand over the years to include words like "bad," "polite" and even "butterfly." Butterfly, according to a Foundation video, is a difficult word for gorillas to sign because it involves interlocking their relatively small thumbs.

Koko eventually learned to sign over 1,000 words and understand about 2,000 words of spoken English. Although some have been skeptical about her comprehension of the motions she produced, her research team believe her emotional and cognitive abilities were sophisticated. Koko pulled distinct signs for words like "scratch" and "comb" together in response to a hairbrush, for example.

Read more: Who was Koko? sign language gorilla dead at 46

Beyond her linguistic abilities, Koko was known for her pet cats. Researchers gave her a kitten she named "All Ball" for her birthday back in 1984. After the gray-and-white kitten's death, she was introduced to several more cats over the years, giving them names including "Lipstick" and "Smokey." Patterson went on to write a book entitled "Koko's kitten."

The signing gorilla's fame was cemented by two National Geographic covers. In 1978, she appeared in a self-taken photograph—an early mirror selfie—and in 1985 she graced the cover clutching All Ball.

Koko, the gorilla known for sign language, has passed away at the age of 46. Here she is on the cover of the 1985 National Geographic. #RIPKoko 🦍

— Nat Geo Channel (@NatGeoChannel) June 21, 2018

Read more: Gorilla gives birth to first son Moke at Smithsonian Zoo

Koko famously met celebrities including Robin Williams and Betty White over the years. The Gorilla Foundation released a tribute video to Williams after he passed away in 2014. Williams called his encounter with the gorilla "a mind-altering experience."

According to the Gorilla Foundation, Koko was a film fan. She reportedly enjoyed watching movies like Free Willy and Babe. And, if the video below is anything to go by, she also had a penchant for fashion.

Koko was born on July 4, 1971, and named "Hanabiko" for the Independence Day fireworks. Hanabiko is Japanese for "fireworks child." Gorillas in captivity can live beyond 50 years, the Smithsonian's National Zoo & Conservation Biology Institute reported. In the wild, they typically reach between 30 and 40 years old.