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Tuesday, September 14, 2010

Bats too have regional accents

ANI


It’s not only humans who have accents, for even bats from different regions speak differently, say Australian scientists.

“Bats in different regions have different calls. You may have the same species on the north and the south coast but they’ll have different calls,” the Age quoted research leader, Brad Law, of the Forest Science Centre in New South Wales, as saying.

For example some bats in Eden - on the NSW south coast - sounded different to bats just north of Batemans Bay, less than 200 kilometres away, he said.

Scientists had long suspected bats had distinctive regional dialects, but it had never been proven in the field, said Mr. Law.

For the study, the team spent months capturing bats at night, identifying each one and recording their calls with special equipment.

Bats use their calls to navigate and hunt, a process called echolocation. They produce high-frequency ultrasounds, which cannot be heard by humans - that hit objects as they are flying along and echo back.

“They are able to form an image of their world from sound,” Dr. Law said.

The team recorded 4000 calls from about 30 species of bat in NSW.

To identify one species’ call from another the researchers developed an automated identification key based on the bats living in a specific region.

“When we go out in the forest, we can record thousands of calls a night, all of which are unknown. If we weren’t able to run them through the automated key it could take months to identify them,” he said.

The researchers developed an identification key for each region, including the lower north coast from Taree to Sydney; the south coast from Sydney to Batemans Bay; and Eden.

While it is still unknown why there are regional call differences, but Dr. Law suspects it may have something to do with their diet because bats use their calls to locate their food.

“Some bats feed on tiny mosquitoes, which means they use a very high-frequency call [to locate them], while others feed on beetles or big moths and use a lower-frequency call,” he said.

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