Researchers have shown that the animals can add small numbers of apples to get their trunks on a bigger food prize

This article is more than 12 years old

This article is more than 12 years old

An Asian elephant bests a science reporter at a simple counting game. Video courtesy of Naoko Irie/University of Tokyo

Elephants are famous for their supposedly superb memory. Now it seems that they are good at simple maths too.

Researchers at the University of Tokyo have found an Asian elephant named Ashya can add small quantities together and correctly identify which is larger.

For example, when researcher Naoko Irie-Sugimoto dropped three apples into one bucket and one apple into a second, then four more apples into the first and five into the second, Ashya correctly identified that the first bucket contained more apples and began munching on her tasty prize.

Ashya and her companions chose the correct bucket 74% of the time. "I even get confused when I'm dropping the bait," Irie told New Scientist magazine.

The elephants' counting abilities are far from unique. Chimps, salamanders and pigeons have shown numerical abilities in lab tests, but what is more impressive for the elephants is that their ability to distinguish between two figures does not get worse when those numbers are more similar.

The elephants that Irie-Sugimoto tested were as good at telling the difference between five and six as they were at distinguishing between five and one.

She presented her findings last week at the International Society for Behavioral Ecology's annual meeting in Ithaca, New York.

It is not obvious why elephants should need this mathematical faculty in the wild. "It really is tough to figure out why [elephants] would need to count," said Mya Thompson, an ecologist at Cornell University who studies elephants.

One possibility is that they use it to keep track of other members of their herd so that no individual is left behind. Asian elephants live in close-knit groups of six to eight. "You really don't want to lose your group members," she said.

Another possibility is that a propensity for simple maths might be a by-product of natural selection for a larger brain, said Irie-Sugimoto.