21.6.06

Vampire bats remember the sound of their victims


They say an elephant never forgets. But the vampire bat may go one better, in a fittingly chilling way. The bats may not only remember the sound of each victim's breath, but also make use of that memory to seek out the same animal for future feeds.The common vampire bat Desmodus rotundus from South America, which feeds exclusively on blood, identifies sounds in the same way that humans use their voices to recognize each other, say researchers.
With cattle blood as a reward, scientists at the Ludwig-Maximilians-Universität in Munich taught three adult bats to associate 10-second clips of human breathing with one of three food dispensers.The bats recognized sound clips and associated them with their corresponding bottle nearly 100% of the time, beating humans undergoing an equivalent test using touch-screen computers. Unlike the vampire bats, humans were unable to classify breathing sounds that were recorded under physical stress.
"Vampire bats are incredibly intelligent and fast," says Daniel Riskin, a professor of biomedical sciences at Cornell University, Ithaca, New York, an expert on vampire bats and their behaviour. "You would think that a person would do pretty well at distinguishing sound because we are so smart and good at communicating. However, the bats were better at it."The way the bats feed is quite dangerous — to them rather than their prey — since their night-time meal involves slicing open the heels of animals a thousand times bigger than they are. The ability to find an open wound left from the night before could be a useful trick. Also, as the bats favour calves over older cattle, their memory might let them return to a particularly succulent meal.
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Full article, Narelle Towie, by: Nature.com
References
Groger U.& Wiegrebe L., . BMC Biology, in press

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