Elephants rumble in the jungle

Each elephant has its own unique, expressive voice, according to new research on how African elephants communicate with each other.

The research, conducted at Disney's Animal Kingdom in Florida, suggests elephants live rich social lives and feel an array of human-like emotions.

The findings also strengthen claims that animal communication can be content-rich and emotionally complex.

While careful human listeners might hear elephant conversations, elephants, particularly chatty females, converse in low-pitched rumbles that human ears often miss, according to two related studies accepted for publication in the journal Animal Behaviour.

Similar to humans ignoring conversations at other tables in a restaurant, elephant strangers do not pay much attention to each other.

"Female friends exchange rumbles even when they are out of sight from one another, and their voices differ from one another, so I believe that they can recognise each other by their voices alone, just as humans and many other social animals can do," says Joseph Soltis, who led the study.

"Females that have known each other for many decades, for example, often engage in rumble exchanges, but females who haven't known each other very long do not respond to each other's calls."

Soltis, a research scientist in bioacoustics at the theme park, and his colleagues placed radio collars on six female elephants that live there. All recorded sounds were computer-analysed and compared with film footage of the elephants.

A unique sound
The recordings indicate that each elephant has its own voice.

"The shapes of their mouths and trunks cause the rumbles from females to sound different from one another," Soltis says.

"It's the same for humans. In the case of our elephants, the sizes and shapes of their vocal tracts, including their trunks, shapes the unique sounds of their rumbles and makes each elephant sound a little different."

Soltis and his colleagues discovered that elephant rumbles became jittery when they appear to feel threatened, such as when a dominant female march by.

Soltis believes fear, and other emotions, are likely to be conveyed in elephant rumbles.

Dominant females within the herd do not necessarily vocalize more than other elephants. And ovulation cycles are also not a factor.

But the closeness of relationships are. Elephant friends and members of families converse more with each other, the study found.

Chatting before dinner
Jeff Kinzley, elephant manager at the Oakland Zoo, agrees with the findings.

"I've even noticed that elephants will have back and forth conversations for a long time before they all suddenly turn around and do something, like go to eat," Kinzley says.

"They wind up walking in a certain order, so it is as though they were deciding who can eat after the matriarch."

Kinzley adds that males converse with each other too, only not as much and usually more when they seem happy.

"Low and slow rumbles seem to indicate happiness," Kinzley says. "We sometimes hear this from both males and females when they appear glad to see us or when they are lounging at a comfortable spot with their trunks resting flat on the ground."

Source: abc.net.au