Elephants move like a 4x4 vehicle with all four legs used to accelerate and brake rather than the "rear-wheel" drive and "front-wheel" braking of other animals.

Scientists have discovered that elephants have eliminated the separation of functions of the front and back legs despite having an anatomy similar to other four-legged animals.

"It's a surprise finding because no one thought that animals would operate in this way. Most four-legged animals are 'rear-wheel' drive, but elephants are clearly four-wheel drive," said Dr John Hutchinson of the Royal Veterinary College in London, who led the study into elephantine motion.

The study was based on the locomotion of six captive Indian elephants.

It found that an elephant's legs produce slightly "bouncy" movements to aid fast walking and running where at least one, and usually two legs are always planted firmly on the ground.

It was thought that elephants had "pillar-like" legs to support their weight.

However, the scientists found that elephants have quite flexible legs that, compared to other animals, produce a relatively small leverage (a measure of how much force is exerted by the muscles) which is between two and three times smaller than predicted.

All four-legged animals tend to use their back legs for acceleration and their front legs for slowing down and stopping, which appears to make elephants unique.

The study is published in the Proceedings of the National Academy of Sciences.