Chantek, a male orangutan who lived at a zoo in Atlanta, was one of the first apes to successfully learn American Sign Language.
The Zoo Atlanta explains that Chantek had a "very unconventional upbringing", as he was an ape who was reared by humans in a human setting.
Chantek, one of the oldest male orangutans in North American zoos, was born at the Yerkes Regional Primate Research Center in Atlanta. He used the visual language to communicate with his caretakers, the zoo said. "He's unique, friendly and easy to communicate with anyone close to him", said Zoo Atlanta Vice-President, Hayley Murphy.
Zoo Atlanta has lost a long-time member of its ape family, officials announced.
Orangutans typically live about 35-45 years in the wild.
Chantek was put on a low-sodium diet, and he was the first awake orangutan to undergo a voluntary echocardiogram to examine his heart's electrical rhythms.
More information on Chantek is available here.
Chantek was among a special group of apes who knew ASL, including Koko, the gorilla, and Washoe, the chimpanzee.
A necropsy, or the animal equivalent of an autopsy, is being performed through the Zoo's partnership with the University of Georgia Zoo and Exotic Animal Pathology Service in the College of Veterinary Medicine.
Cardiac disease, zoo officials said, is the primary cause of death among great apes in zoological populations.
The cause of Chantek's death is not known, but zoo vets had been treating him for progressive heart disease.
He eventually learned hundreds of words and, according to a TEDx Chattanooga presentation from Miles, invented his own gestures for "annoyed", "scatter", "eye drink" (contact lens solution) and "tomato toothpaste" (ketchup). All four great ape taxa are endangered or critically endangered. Experts predict that Sumatran orangutans could be extinct within 10 years without targeted conservation efforts.