Bat species use remarkable stealth technique to sneak up on their prey

Washington, Aug 24 : Scientists in the UK have discovered that a rare British bat has developed remarkable stealth technique to sneak up on moths.

Holger Goerlitz of the University of Bristol in England said that western barbastelle bats in Europe typically ping out their echolocation calls softly enough to locate a moth for dinner before the moth hears them coming.

This bat version of whispering is 10 to 100 times lower in amplitude than other aerial-hunting bats' echolocation calls. Those rank more in the range of jet engines and the vuvuzelas blaring at the latest World Cup, reported Discovery News.

The researchers set up a microphone array where bats swooped through at night to let researchers figure out the bat's position for each of more than 100 calls.

This array also let the researchers answer the critical question of whether the barbastelle's softer echolocation was soft enough for stealth attacks on eared moths.

"The use of low-intensity echolocation calls when foraging for airborne prey is to my mind the clearest example of an adaptation that can best, and perhaps only, be explained as a means of eluding detection by eared insects," said behavioural ecologist John Ratcliffe.

Gorelitz concluded that there doesn't seem to be any other evolutionary advantage to keeping the noise down besides stealth in hunting. Of course, the trade off is more sneak power but a weaker ability to detect potential food from a longer distance.

The study appears online in a Current Biology paper.

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