Science News: Bats using sound to find their way in the dark boom louder than home fire alarms and rock concerts, according to new measurements.

Fortunately all that noise stays at frequencies too high for human hearing reports Annemarie Surlykke of University of Southern Denmark in Odense. She and Elisabeth K.V. Kalko of the University of Ulm in Germany recorded and analyzed the yells bats emitted while hunting outdoors at the Smithsonian Tropical Research Institute’s field station on Barro Colorado Island in Panama.

One of the two loudest bats on record, the bulldog bat (Noctilio leporinus) blasted out echolocation sounds in the range of 137 decibels, compared to 108 decibels for home smoke detectors.

Species from four bat families made sounds that, at a distance of 10 centimeters, ranged between 122 and 134 decibels (measured on a scale that sets the threshold of human hearing at 0 decibels), the researchers say in the April PLoS One. Two species flying over open water made the loudest sounds yet recorded for any bat, averaging around 137 decibels and even hitting 140.

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