By: Eleanor Liang
Five years ago, when I was only four, I was sitting in the movie theater, watching the movie Ariel, and munching on some popcorn. Absent-mindedly, I wondered what it was like to have a mermaid as a pet and have her sing songs with me underwater.
But now I know that mermaids’ songs might not be as charming as Ariel’s singing, the reason being the science behind mermaids and our ears.
“Mythical mermaids are often known for their fishy tails and alluring songs. But if you were underwater with one, her tunes wouldn’t sound quite like they do in the movies. And you might struggle to understand the words as Ariel or her other mermaid friends burst out singing,” reported Science News Explorers.
“Even next to a mermaid, the song would sound muffled and would seem to come from all around,” comments Jasleen Singh, who studies human hearing at Northwestern University in Evanston, Ill.
“You could still make out what she is saying, but it would sound fuller with less clarity,” Singh says.
They aren’t quite wrong.
The hearing explanation
So why do our mythical relatives’ songs not sound so melodious? That’s partly because of our hearing system.
Sound is produced by vibrations. If you touch your throat and talk, you can feel your vocal cords vibrating. These vibrations can travel through the three states of matter: solids, liquids, and gasses.
In each medium, atoms get pushed around by a sound source’s back-and-forth motion. They bump into each other like a line of falling dominoes, and they collide, making noise and spreading sounds.
Human hearing starts when things vibrate and sound waves enter the ear. The waves vibrate the eardrum. The eardrum sends the vibrations to three little bones. One of them taps on a snail-shaped structure called the cochlea. It converts vibrations into electrical symbols and sends them to the brain.
However, when underwater, it’s different. Since water plugs our ears, we rely on sound waves vibrating directly in our skulls. This might happen on land too, but in water, it’s more powerful. That’s because the water and our bones have similar densities.
“When sound waves gently rattle the skull, ‘that is directly stimulating the inner ear — the cochlea itself,’” Singh says to the Science News Explorers, describing the way hearing is underwater.
This concept is called “bone conduction.” We, however, are much more accustomed to sound waves shaking our eardrums, which means the sound quality of bone conduction isn’t as good on land.
Also, it’s hard to figure out where a sound is coming from. Since sound travels faster in liquid than air, underwater noises ring everywhere.
“That’s because the particles that make up liquids are closer together. In water, there is virtually no time difference between sound hitting each ear. That makes underwater noise sound very full, like it’s coming from everywhere,”Science News Explorers explained.
Their hearing
The mermaids might have evolved more like aquatic animals to hear their mermaid friends.
“Marine mammals, such as whales, dolphins and seals, hear in a way very similar to humans,” notes Colleen Reichmuth. A biologist, she studies marine mammals at the University of California, Santa Cruz.
“The lower jaw of dolphins and some whales contains fat that directs sound to the bony middle ear. This fat has a “special chemical composition that makes it really suitable for transmitting acoustic waves,” says Laela Sayigh, another marine biologist.
Some marine animals have convertible hearing. On land, the animals can open their ear holes to pick up vibrations traveling through the air. But when underwater, their ear tissue swells with fluid, plugging the holes. This can help transfer sound from the water to the cochlear.
Those features might help the mermaid hear her underwater fish and people without any ear surgery.
If the mermaid’s voice is more like that of a marine animal, their vocal systems have a lot of space for enhancement.
Whales, dolphins, seals, and other marine mammals can “sing” underwater, creating complex noises with musical rhythms. They produce sound by passing air along tissues to undulate them, similar to a human’s voice box. “But unlike people, who must breathe out to make noise, many of these sea creatures don’t need to expel air from their mouths or blowholes to produce sound,” Science News Explorers contradicted.
“Underwater, air is a precious commodity,” says Joy Reidenberg. “If whales exhaled when using their voices, they would have to keep resurfacing for more air. That would interrupt their lengthy songs,” Reidenberg says.
Science News Explorers commented, “She studies animal anatomy at the Icahn School of Medicine at Mount Sinai in New York City.”
“Instead, whales and dolphins can move air around in their bodies and even reuse it. This air recycling system would certainly help a mermaid sustain conversation or song below the surface,” Reichmuth says.
“If you met a mermaid, she might have both fish-like and mammalian structures to communicate with her underwater friends. Motion-detecting cells may line her tail, and her ears may work like a seal’s to hear both in and out of water,” hypothesizes Science News Explorers. “ She would probably recycle her body’s air supply to talk and sing without having to keep resurfacing. But her conversations may also be sprinkled with teeth chattering, clapping — and even farting.”
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