London - Apes could be as good at arithmetic as many four-year-old children with a female chimpanzee called Ai able to place Arabic numerals from 1 to 9 in ascending order, researchers reported in the UK magazine Nature.
Even more importantly, she can also remember a sequence of up to five numbers at a time. This puts her at the same level as many pre-school children. Two Japanese researchers at Kyoto university trained Ai to use a touch sensitive screen and to recognise Arabic numerals. They then worked out a way of testing her memory.