Whales Adjust Their Hearing Sensitivity
Have you ever wanted to turn down the volume at a deafening concert or noisy bar? Envy the whale: a new study finds that toothed whales can reduce their own auditory sensitivity when they expect a loud sound. The work is presented at this week’s Acoustics 2012 meeting. [Paul E. Nachtigall and Alexander Ya Supin, Immediate changes in whale hearing sensitivity]
Whales and dolphins rely on their responsive hearing to interpret returning echolocation clicks. Previous research suggested that these marine mammals could dull their hearing before uttering outgoing echolocation clicks, which are very loud. Could they use the same coping mechanism for external noises?
To find out, researchers trained a false killer whale that a loud noise would always follow a brief warning signal. Then, they attached suction-cup sensors to the outside of the whale’s head and played the signal. The sensors measured brainwaves that indicated the whale did reduce its hearing sensitivity in expectation of a clamor. The researchers hope to test other species as well.
Loud noises from ships can disturb whales. To accommodate marine life, perhaps vessels could emit signals before making a ruckus, warning whales to tune us out.