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littlemissmartypants

(25,713 posts)
Mon Nov 25, 2024, 03:53 AM Nov 25

First successful test of wild minke whales reveals they have ultrasonic hearing

Nov 23, 2024

First successful test of wild minke whales reveals they have ultrasonic hearing

by Bob Yirka , Phys.org

A team of marine biologists from Norway, the U.S. and Denmark has conducted the first hearing test of a live baleen whale. For their study published in the journal Science, the group corralled a pair of wild minke whales and recorded their brain waves.

Concerned about how human-produced ocean noises may impact the creatures that live in the sea, marine scientists want to learn more about the animals' hearing capabilities. In this new study, the research team devised a means for testing the hearing of two wild baleen whales by recording their brain waves as they listened to recorded sounds.

The research team chose the minke whales as test subjects because of their relatively small size compared to other whales. To capture their brain waves, they studied their swimming routes through a narrow channel between two islands off the coast of Norway. Next, they placed netted barriers near the area that directed the whales to a small enclosure.

Once they had trapped two whales, they pulled up a net below them, bringing them to the surface. This allowed the researchers to affix electrodes to their heads. The team used the electrodes to record the whales' brain waves as they responded to sounds played from nearby speakers. One of the whales was tested for a half-hour, the other an hour and a half. The researchers then released the whales back into the wild.
Snip...more...(two additional paragraphs)...
https://phys.org/news/2024-11-successful-wild-minke-whales-reveals.html



Ultrasonic hearing is a recognised auditory effect which allows humans to perceive sounds of a much higher frequency than would ordinarily be audible using the inner ear, usually by stimulation of the base of the cochlea through bone conduction. Normal human hearing is recognised as having an upper bound of 15–28 kHz,[1] depending on the person.

Ultrasonic sinusoids as high as 120 kHz have been reported as successfully perceived. Two competing theories are proposed to explain this effect. The first asserts that ultrasonic sounds excite the inner hair cells of the cochlea basal turn, which are responsive to high frequency sounds.[2] The second proposes that ultrasonic signals resonate the brain and are modulated down to frequencies that the cochlea can then detect.[3]

Researchers Tsutomu Oohashi et al. have coined the term hypersonic effect to describe the results of their controversial study supporting audibility of ultrasonics.[4]

By modulating speech signals onto an ultrasonic carrier, intelligible speech has also been perceived with a high degree of clarity, especially in areas of high ambient noise. Deatherage states that what humans experience as ultrasonic perception may have been a necessary precursor in the evolution of echolocation in marine mammals.[5]
https://en.m.wikipedia.org/wiki/Ultrasonic_hearing


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First successful test of wild minke whales reveals they have ultrasonic hearing (Original Post) littlemissmartypants Nov 25 OP
Whales conversing afterward EYESORE 9001 Nov 25 #1
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