Ai, a "genius” chimpanzee who could recognise more than 100 Chinese characters and the English alphabet, has died aged 49, Japanese researchers said.
"Ai, which means love in Japanese, took part in studies on perception, learning and memory that advanced our understanding of primate intelligence,” the Centre for the Evolutionary Origins of Human Behaviour at Kyoto University said in a statement.
She died on Friday from multiple organ failure and ailments related to old age, the school said.
Aside from mastering Chinese characters and the alphabet, Ai could also identify the Arabic numerals from zero to nine and 11 colours, primatologist Tetsuro Matsuzawa said in 2014.
In one study, Ai was presented with a computer screen displaying the Chinese character for pink, along with a pink square and an alternative purple square. The chimpanzee correctly chose the pink square, Matsuzawa said.