Wed, Mar 12, 2014 - Page 6 News List

Elephants can gauge threat from human voices: study

DISCERNING EARS:A study of wild elephants found that they could tell if a human posed a threat by listening to the person’s voice for clues about gender and ethnicity

AP, WASHINGTON

Bull elephants lock their tusks to greet each other at dawn in the Amboseli National Park in Kenya on Oct. 9 last year.

Photo: EPA

Wild elephants can distinguish between human languages, and they can tell whether a voice comes from a man, woman or boy, a new study says.

That is what researchers found when they played recordings of people for elephants in Kenya. Scientists say this is an advanced thinking skill that other animals have not shown. It lets elephants figure out who is a threat and who is not.

The result shows that while humans are studying elephants, the clever animals are also studying people and drawing on their famed powers of memory, study author Karen McComb said.

“Basically they have developed this very rich knowledge of the humans that they share their habitat with,” said McComb, a professor of animal behavior and cognition at the University of Sussex in England.

“Memory is key. They must build up that knowledge somehow,” she said.

The study was released on Monday in the Proceedings of the National Academy of Sciences.

McComb and colleagues went to Amboseli National Park in Kenya, where hundreds of wild elephants live among humans, sometimes coming in conflict over scarce water.

The scientists used voice recordings of Masai men, who on occasion kill elephants in confrontations over grazing for cattle, and Kamba men, who are less of a threat to the elephants. The recordings contained the same phrase in two different languages: “Look over there. A group of elephants is coming.”

By about a two-to-one margin, the elephants reacted defensively — retreating and gathering in a bunch — more to the Masai recording because it was associated with the more threatening humans, study co-author Graeme Shannon of Colorado State University said.

“They are making such a fine-level discrimination using human language skills,” Shannon said. “They’re able to acquire quite detailed knowledge. The only way of doing this is with an exceptionally large brain.”

They repeated the experiment with recordings of Masai men and women. Since women almost never spear elephants, the animals reacted less to the women’s voices. The same thing happened when they substituted young boys’ voices.

“Making this kind of fine distinctions in human voice patterns is quite remarkable,” said Emory University animal cognition expert Frans de Waal, who was not part of the study.

While it shows quite a bit about elephant intelligence and adaptability, it also indicates a problem, said biologist Josh Plotnik, founder of Think Elephants International, a research and advocacy group.

“This is both fascinating in that it supports evidence we already have that these animals are behaviorally quite flexible, but also sad because it suggests that the conflict between humans and elephants is growing,” Plotnik, who was not part of the study, wrote in an e-mail.

In another experiment McComb and Shannon altered female and male voices, making female voices sound male by lowering their tone and resonance, and males sound female by raising their pitches.

Those kinds of changes fool most humans, but the clever elephants were not tricked, McComb said. They still moved away from the altered male voices and not the altered female voices, she said.

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