The chimpanzee from Kyoto University known for an extraordinary memory for numbers is Ayumu.
Ayumu is a male chimpanzee born in 2000 and the son of Ai, another famous participant in Kyoto University's long-running Ai Project. Researchers at the Primate Research Institute studied his ability to remember the order of briefly displayed numerals on a touch-sensitive screen.
In the best-known test, numbers appeared briefly in different locations before being replaced by identical squares. Ayumu could touch the squares in numerical order, often faster than human university students who had received comparable training. His performance drew worldwide attention because it suggested that young chimpanzees may possess particularly strong visual working memory.
The result is sometimes simplified as proof that chimpanzees have universally better memories than humans. That is too broad: later researchers disputed aspects of the comparison, including the effects of practice and testing conditions. Ayumu's achievement is more precisely a striking example of rapid numerical-sequence memory in a chimpanzee, rather than evidence that he understood mathematics like a human.