One of the world’s best-known and most well-loved gorillas, Koko, died in her sleep on Tuesday morning of this week, the Gorilla Foundation announced.

A western lowland gorilla, Koko was an ambassador for her species. She was known all over the globe for her awe-inspiring mastery of sign language, her deep affection for a kitten she named All Ball, and the friendships she made with many, including the late Robin Williams and the late Fred Rogers.

Koko demonstrated for the world that animals are communication-capable, empathetic creatures with emotions and cognitive ability, and that they are worthy of our love and respect.

More from LifeZette TV

MORE NEWS: Ep 78 | Democrats: Violence, Destroying American Institutions, Vote for Us or Else!

She was the subject of a number of documentaries, and appeared on the cover of National Geographic multiple times.

One of the most memorable is of Koko taking a picture of herself in a mirror.

Do you agree that protesting is acceptable, but rioting is not? Yes No Email Address (required) By completing the poll, you agree to receive emails from LifeZette and that you've read and agree to our privacy policy and legal statement Results Vote

On #NationalSelfieDay of all days, Koko’s 1978 “selfie” seems particularly fitting.

Koko the gorilla, who appeared on our cover, could chat, tease, and even argue with scientists using sign language. She has died at the age of 46. pic.twitter.com/JX9vlFzpiI — National Geographic (@NatGeo) June 21, 2018

Koko was trained by Dr. Francine “Penny” Patterson, who began working with her to teach her sign language a year after her birth at the San Francisco Zoo in 1971.

MORE NEWS: Democrats Are Planning the Biggest Heist in American History

The Gorilla Foundation noted in a release, “The foundation will continue to honor Koko’s legacy and advance our mission with ongoing projects including conservation efforts in Africa, the great ape sanctuary on Maui, and a sign language application featuring Koko for the benefit of both gorillas and children.”

The Gorilla Foundation asks that condolences be sent to [email protected].

Rest in peace, Koko.

RIP Koko. You did so much to break down that wall many of us perceive between humans and other species. https://t.co/TBXwmccVb7 — David Steen, Ph.D. (@AlongsideWild) June 21, 2018

R.I.P. Koko

The 'signing gorilla' died at 46 at the sanctuary where she lived for decades–and occasionally made some very famous friends. pic.twitter.com/QgkHHxj9BO — Reggie Aqui (@reggieaqui) June 21, 2018

Oh no, Koko died. Koko and Mr. Rogers are some of the greatest photos of our time. RIP https://t.co/aXhTdn6b31 pic.twitter.com/95RwuHYars — pourmecoffee (@pourmecoffee) June 21, 2018

RIP Koko. The 'Koko's Kitten' book was a staple of my childhood in the 1980s. pic.twitter.com/NnPbtuNSHV — Marcus Gilmer (@marcusgilmer) June 21, 2018

Michele Blood is a Flemington, New Jersey-based freelance writer and a regular contributor to LifeZette.

(photo credit, homepage and article images: The Gorilla Foundation)