Ai, a female chimpanzee famous for her cognitive skills, has died at 49, according to the Kyoto University's Center for the Evolutionary Origins of Human Behavior. She passed away on January 9 due to old age and organ failure, surrounded by staff. Ai was born in western Africa and arrived in Japan in 1977, where she became the namesake of the Ai Project—a research initiative studying the 'chimpanzee mind.'

Notable findings included her ability to use numbers and identify colors. Researchers provided Ai with a special keyboard at 18 months to facilitate studies on her memory and cognition. By five years old, she could master numerical naming from one to six and name the color and object of 300 samples.

When not engaged in studies, Ai enjoyed drawing and painting, often using markers creatively without needing food rewards. A quirky moment in her life includes escaping her cage using a key. Ai gave birth to a son, Ayumu, in 2000, who is also recognized for his impressive memory. In 2017, Ai's artwork was honored with a scarf for primatologist Dame Jane Goodall, marking the 40th anniversary of the Ai Project.