Researchers have identified an elephant in Kenya that makes traffic noises. In quiet moments after dark, Mlaika the semi-captive orphan astonished experts by making the sound of a distant truck revving up.
In formal terms, Joyce Poole of the Amboseli elephant research project in Tsavo national park and colleagues report in the magainze Nature yesterday, Mlaika is evidence that vocal learning in response to auditory experience has evolved in elephants.
So pachyderms are as nimble as parrots, starlings, bats, whales and dolphins when it comes to vocal imitation. Parrots have learned to curse in human, gorillas to deploy sign language. And now an elephant has articulated lorry.
Mlaika, a 10-year-old adolescent, roams freely by day, but shares a pen with other orphans at night. When Poole realized that Mlaika's sounds were just like one of the trucks that thundered along the Nairobi-Mombasa highway, a mile or two distant, she felt nobody would believe her.
So she got in touch with Peter Tyack, an expert in marine mammal noises at Woods Hole Oceanographic Institution in Massachusetts. They agreed that Mlaika made a convincing imitation of a heavy lorry.
"I was sometimes unable to distinguish between the distant trucks and Mlaika's calling. I had to take my earphones off to tell what was a nearby elephant and what was a distant truck," Poole said.
"This is what first made me wonder whether she could possibly be imitating the truck sounds. Later, when I played the sounds to people who didn't know it was an elephant calling, I asked people what they thought it was. Their answer was usually `a truck.'"
Mlaika talks to other elephants and her keepers like a normal elephant.
The unexpected sound of distant traffic from inside a stockade on the savannah was the first evidence that something unexpected had evolved in an elephant community.