An exceptionally intelligent Japanese chimpanzee, Ai, has died peacefully at the age of 49, Kyoto University’s Primate Research Centre confirmed. Staff members said Ai passed away calmly due to old age and organ failure, with caregivers by her side.
The news has prompted an outpouring of tributes from scientists and animal lovers worldwide, who credit her with transforming global understanding of animal cognition.
Researchers brought Ai to Japan from West Africa in 1977 and soon placed her at the centre of a long-term scientific project on chimpanzee intelligence and memory. Over the years, she demonstrated remarkable abilities that consistently impressed experts. Scientists trained her using a specialised computer-based keyboard, and she quickly learned to recognise numbers, colours and objects. By the age of five, Ai could accurately identify a wide range of symbols and respond to complex tasks.
Moreover, research findings showed that Ai could recognise more than 100 Chinese characters, the English alphabet, numbers from zero to nine and 11 distinct colours. She also displayed creativity, often drawing and painting on paper during enrichment activities at the centre.
Influence on research and future generations
Ai’s impact extended beyond her own achievements. In 2000, she gave birth to a son, Ayumu, who later gained international attention for his exceptional memory skills in laboratory tests. Consequently, scientists used both mother and son to deepen their understanding of cognitive development.
Ai’s intelligence featured in numerous documentaries, academic studies and media programmes. Prestigious journals, including Nature, published research inspired by her abilities. Even after her death, experts say her legacy will continue to guide future studies on animal intelligence and ethical research practices.
