United News International (UNI)- The Gorilla Foundation announced June 21 that the beloved western lowland gorilla, Koko, passed away at the age of 46.

The cat-loving gorilla was born at the San Francisco Zoo in 1971.

Koko learned sign language early in life and understood over 2,000 words in spoken English.

She famously asked her caretakers in sign language for a kitten for Christmas in 1983.

Koko cared for the kitten as though it were her baby.

Her love for felines led to the production of the children’s book, “Koko’s Kitten” which told the story of Koko and her furry friend.

Famous celebrities including Robin Williams, Mister Rogers and Betty White also developed unique relationships with Koko over the years.

She made headlines in 2016 for her mourning in reaction to Robin Williams’ death.

The Gorilla Foundation said Koko taught the world so much about the emotional capacity and cognitive abilities of gorillas.