Bats' Dynamic Ears Contribute to Super Sonar Abilities

Echolocating bats depend upon their sense of hearing to navigate, find food, and avoid obstacles in the dark. A new study shows that their ears aren't just passive biosonar receiving antennae - bats can change the shape of their outer ears to increase the flexibility and efficiency of their hearing.The study, by a team from Virginia Tech and Shandong University in China, was published in Physical Review Letters.Horseshoe bats, like the one pictured at left, can deform the shapes of their ears in a manner that changes the bat's spatial hearing sensitivity. The bats can switch their ears from one configuration to another in just a tenth of a second.Rolf Müller led the research team, which used a combination of techniques including high-speed stereovision and high-resolution tomography to capture the extremely fast movements of the bats' ears and then determine how those changes affected hearing. The researchers concluded that the configuration of the bat's ears determines the types of information it will get back from its echolocation emission. Different ear arrangements will create different "spotlights" for their ultrasonic hearing. By quickly switching ear shapes, a bat can rapidly scan its environment for as much acoustic information as possible, giving it a highly detailed acoustic map of its surroundings.File under: the millionth reason bats are awesome.