When a trainer dropped three apples into one bucket and one apple into a second, then four more apples in the first and five more in the second, the pachyderm recognised that three plus four is greater than one plus five, and snacked on the seven apples.
“I even get confused when I’m dropping the bait,” says Dr Naoko Irie-Sugimoto, a researcher at the University of Tokyo, Japan, speaking to NewScientist.com.
Dr Irie-Sugimoto presented her findings last week at the International Society for Behavioral Ecology’s annual meeting in Cornell University, Ithaca, New York.
Moreover, Dr Irie-Sugimoto found that as well as summing small numbers with almost 90 per cent accuracy, elephants can discriminate between small numbers.
They can tell similar quantities apart, when most species are best when there is a big difference.
The four elephants that she tested distinguished between five and six apples as well as they did between five and one. They picked the bucket with the most fruit three quarters of the time, on average, far above 50-50.
The skill now poses a question: why did they evolve the means to count? Mya Thompson, an ecologist at Cornell University who studies elephant communication, points out that studies in India by Raman Sukumar shows that Asian elephants live in close-knit groups of six to eight, and they may count one another to make sure the herd sticks to together. “You really don’t want to lose your group members,” she says.
“Elephants seem to know where family members are, for which counting them might be quite useful,” adds Prof Friz Vollrath of Oxford University.