Natures wonders: How whales hear (Introduction)

by David Turell @, Friday, January 30, 2015, 19:22 (1896 days ago) @ David Turell

Probably bone conduction:

"There are two ways sound can reach a whale's tympanoperiotic complex (TPC), an "interlocking bony puzzle" of ear bones that is rigidly attached to the skull. One way is for the sound's pressure waves to travel through the whale's soft tissue to their TPC, but this becomes ineffective once sound waves are longer than the whale's body, Cranford said.

"The second way is for sounds to vibrate along the skull, a process known as bone conduction. Unlike pressure waves passing through soft tissue, longer waves lengths are amplified as they vibrate the skull.

"When Cranford and Krysl modeled various wavelengths traveling through their computerized skull, they found that bone conduction was approximately four times more sensitive to low frequency sounds than the pressure mechanism. Importantly, their model predicts that for the lowest frequencies used by fin whales, 10 Hz -- 130 Hz, bone conduction is up to 10 times more sensitive.

"'Bone conduction is likely the predominant mechanism for hearing in fin whales and other baleen whales," Cranford said. "This is, in my opinion, a grand discovery.'"

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