The broad, squished nose of horseshoe bats may not look pretty, but it enables them to navigate and hunt. New research published online today in theJournal of the Royal Society Interface describes how the furrows above the main nose lobes in horseshoe bats (Rhinolophidae) help them focus sound beams and reduce interference from clutter in the environment. Bats use echolocation—emitting high-pitched calls and analyzing the echoes that bounce back to them—to move around and feed. Scientists made physical models of a horseshoe bat's head and separate models of its facial features to see how the furrows affected sound transmission. They found that as the bat emits sound through its nose, the folds reduce the size of the main lobes, thereby tightening the focus of the sound beam. While this lowers the bat's ability to localize prey, it also reduces interference from clutter in habitats like a forest. The findings contradict previous research, which found that the furrows broadened the sound beam, possibly enabling the bats to track how high off the ground they were. The authors of the new study argue that the frequency modification detected by previous scientists occurred in the wrong range to allow this kind of tracking.
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