Elephants have passed a test of intelligence which scientists say has "profound" implications for our understanding of their mental capabilities. They were found to be capable of performing a task that showed they have a level of selfunderstanding that is rare in the animal world and defeats humans until they are about two years old.

Elephants have already shown they can recognise themselves in a mirror, something that is thought to be relatively rare among animals.

The new test, which was described as "deceptively simple", involved picking up a stick and handing it to a researcher.

But sometimes the stick was tied to a mat on which the elephant had to stand to reach it. This meant they had to realise their own body was preventing them from passing on the stick and get off the mat in order to complete the task.

The scientists behind the study said animals capable of this kind of behaviour may also be better at empathising and be able to consider someone else's perspective.

And that could have implications for the way conflicts between humans and elephants should be handled in places where the two species are competing for land and resources.

Dr Josh Plotnik, a visiting researcher at Cambridge University, said: "This is a deceptively simple test, but its implications are quite profound."

"The elephants understood that their bodies were getting in the way, so they stepped aside to enable themselves to complete the task. In a similar test, this is something that young children are unable to understand until they are about two years old.

"This implies that elephants may be capable of recognising themselves as separate from objects or their environment. This means that they may have a level of selfunderstanding, coupled with their passing of the mirror test, which is quite rare in the animal kingdom."

The test was an adapted version of one used on human children. In that test they are asked to push a trolley attached to a matt, which they normally stand on as they approach the trolley.

Only when they reach the age of about two do the humans realise they have to get off the matt in order for the trolley to move.

Twelve female elephants aged from four to 40, who live at the Anantara Golden Triangle camp in Chiang Rai, Thailand, took part in the tests.