By Susan Milius
Exposing a bottle-nosed dolphin to a couple of minutes of nearby sonar pinging could cause some temporary hearing impairment, a new test finds.
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What sonar does to marine mammals has become a hotly debated topic in recent years, as beaked whales and other species have stranded in shallow water and died after naval training exercises in the area.
For the first time, researchers have played recordings of actual naval sonar to a marine mammal and tested its hearing after progressive step-ups in intensity over a couple of months, says Aran Mooney of the Woods Hole Oceanographic Institution in Massachusetts.