Mimicry of trucks and zoo-mates shows range of vocal repertoire.
They say that elephants never forget. Now the creatures have shown that, when it comes to the fine art of vocal mimicry, they're not averse to learning new tricks either.
Researchers have recorded two African elephants (Loxodonta africana) that are adept mimics. One does a decent impression of an Asian elephant, and another is, remarkably, a dead ringer for a passing truck. The skilful impressions are far from the traditional grunts of an average African elephant.
The discovery adds elephants to a notably short roll call of animal mimics, which includes little more than humans, sea mammals, bats and birds. "The surprising thing is how few mammals show an ability to modulate their sounds," says Peter Tyack of Woods Hole Oceanographic Institution in Massachusetts, who led the study.
“Mlaika seemed to be making sounds like a truck, of all things. Peter Tyack , Woods Hole Oceanographic Institution”
The two elephants in question are Mlaika, an adolescent female living in a semi-captive group in Kenya, and Calimero, an adult male who lived for 18 years with two Asian elephants at a Swiss zoo. Calimero, perhaps unsurprisingly, mimics the typical chirp noises of Asian elephants (Elephas maximus). "But Mlaika seemed to be making noises like a truck, of all things," Tyack recalls.
He and his team analysed the sounds and found that their characteristics were definitely unlike those of sounds made by more conventional African elephants. The researchers present their results in this week's Nature1.
Tyack and his team think Mlaika's habit is due to her upbringing, which was within earshot of a road. Whatever the case, she has provided valuable insight into what elephants might be able to do with their voices. "Often it's the odder examples, like a parrot talking, that first give us a hint at what's going on," he explains.
"In both of these cases it seems that they were deprived of proper role models," says elephant expert Katharine Payne of Cornell University in Ithaca, New York. It would be interesting to know whether they ever heard true African elephant calls in their youth, she adds.
Tyack suspects that elephants' versatile vocal skills may help them recognize each other and therefore bond social groups together. He adds that other skilful vocalists, such as bats and dolphins, use sound for a range of social tasks including hunting and navigating.
It's a plausible idea, agrees Payne. Elephant societies are complex, and members frequently call over very long distances, even when there is no other elephant in sight.
Strong mimicking skills might even help the elephants to adopt family-specific calls, much as humans are identified by their family surnames, speculates Vincent Janik, who studies animal communication at the University of St Andrews, UK. "The next step is to look at family groups and see if they have a single call," he says.
PooleJ. H., TyackP. L., Stoeger-HorwathA. S. & WatwoodS.Nature, 434. 455 - 456 (2005).
Woods Hole Oceanographic Institution