Passing of Ai, the Chimpanzee (January 9, 2026)

On January 9, 2026, at 4:04 p.m., Ai, a chimpanzee who dedicated many years to the study of the evolutionary origins of the human mind at Kyoto University, passed away at the age of 49. Her passing was due to advanced age and multi-organ failure, and she took her last breath while being watched over by the staff members.

Since her arrival in 1977, Ai participated as a key research partner in various studies, ranging from the evolutionary origins of language to the precise examination of perception, learning, and memory. Her contributions established an experimental framework for understanding the "chimpanzee mind" and provided a vital foundation for exploring the evolution of human cognition. Driven by her natural curiosity, Ai participated actively in these studies and became the first to reveal many different facets of the chimpanzee mind to us. Consequently, the project initiated in 1978 by Professor Yasuko Murofushi was named the 'Ai Project' in her honor.