Chimpanzees have come out tops in a human versus monkey battle-of-the-brains in Japan.
Researchers pitted young chimps against human adults in two tests of short-term memory, and overall, the chimps won.
The results challenge the belief that humans are superior to chimpanzees in all cognitive functions, said researcher Tetsuro Matsuzawa of Kyoto University.
"No one can imagine that chimpanzees - young chimpanzees at the age of five - have a better performance in a memory task than humans," he said.
Mr Matsuzawa, a pioneer in studying the mental abilities of chimps, said even he was surprised.
Results of the memory testing showed that while the chimps were no more accurate than humans, they were faster.
One test included three five-year-old chimps who'd been taught the order of Arabic numerals one through nine, and a dozen human volunteers.
They saw nine numbers displayed on a computer screen. When they touched the first number, the other eight turned into white squares. The test was to touch all these squares in the order of the numbers that used to be there.
Even after six months of training, the students still couldn't keep up with their chimpanzee competitors.
