On the main trunk road: the elephant that imitates traffic noises

An elephant who can mimic the noise of a passing truck so well it was difficult to tell the two sounds apart has given scientists insights into the superior intelligence of the gentle giants.

An elephant who can mimic the noise of a passing truck so well it was difficult to tell the two sounds apart has given scientists insights into the superior intelligence of the gentle giants.

The calls of Mlaika, an orphaned 10-year-old female kept in semi-captivity, were clear imitations of the distant noises of trucks she heard on a road two miles from her night-time stockade in Tsavo, Kenya, scientists said.

Zoologists say the discovery shows that elephants have a much wider repertoire of sounds and vocalisations than hitherto believed, which indicates they are capable of far more subtle communication than was once supposed.

A scientific analysis of Mlaika's calls showed they were based on the same range of sound frequencies emitted by a truck's engine as it travelled along the Nairobi-Mombasa highway.

Scientists, led by Joyce Poole of the Ambolesi Trust for Elephants in Nairobi, believe that the discovery of vocal mimicry in elephants shows they have a natural ability to imitate each other's sounds to strengthen social bonds within a family group.

In a study published today in the journal Nature, the researchers report they have discovered a similar ability to imitate alien sounds in a 23-year-old male African elephant who has lived for 18 years at Basle Zoo in Switzerland with two female Asian elephants.

Calimero was recorded making the same high-pitched "chirping" sounds produced by female Asian elephants. The chirps have never been recorded in wild African males, Dr Poole said: "He was probably trying to be part of that social group and to join in with them. Eventually it became about the only sounds he made."

Vocal mimicry in animals is relatively rare and is usually confined to marine mammals, birds, bats and primates. Scientists believe the ability to imitate sounds indicates the importance of vocalisation to form bonds within a social group or to advertise sexual availability, such as birdsong.

But it is only when an animal starts to mimic an alien sound, such as pet parrot talking in its owner's voice, that the mimicry becomes apparent. Crows have been recorded imitating the sound a creaking farm gate and a captive seal in a Boston zoo has been heard saying "hello" with a Boston accent.

Mlaika emitted the truck-like calls for several hours after sunset, the best time for the transmission of low-frequency sounds in the African savannah, said Stephanie Watwood, a member of the research team at the Woods Hole Oceanographic Institution in Massachusetts.

"Often the first time you get to know about vocal learning is when you get an animal learning something outside of their normal repertoire of sounds," Dr Watwood said. "They can learn to imitate the sounds they hear around them. It's a bit like a parrot learning a song or a phrase they hear spoken to them."

Elephants are known to produce much deeper, ultrasonic noises that are difficult to hear with the human ear. It is believed that these calls, which can be heard over long distances, are used to communicate between family groups many miles away.