Oceanic researchers proved that "Jaws" isn't the silent killer it's depicted as after recording shark noises for the first time, as detailed in a study in the Royal Society Open Science journal.
"I was very surprised. I was under the assumption that sharks don't make sounds," head author Carolin Nieder, a marine biologist at Woods Hole Oceanographic Institution in Massachusetts, told ScienceAlert.
The scientist, who hails from New Zealand, inadvertently discovered this great-white noise in 2021 while researching the hearing capabilities of the rig shark -- a small inshore species that inhabits waters off of her motherland.
While handling one of the predators, Nieder noticed that it made a clicking snapping sound akin to an electric spark, the New York Times reported.
The development was particularly jarring as, unlike other fish -- which can vibrate their swim bladders to generate noise -- sharks "were thought to be silent, unable to actively create sounds," the scientist said.
To get to the bottom of the fishy soundtrack, the scientist and her team observed the behavior of 10 sharks in a tank outfitted with underwater microphones between May 2021 and April 2022.
They found that all 10 rigs would "produce clicking sounds underwater" while being handled or transferred between tanks, per the study, ABC News reported.
On average, the specimens emitted nine clicks during a 20-second period, with most occurring during the initial 10 seconds.
The source of the sounds is still unclear, but researchers believe that the rigs snap together their plate-like teeth -- used to crush crustaceans -- to create percussive noises, according to CNN.
As they didn't click while feeding or swimming, researchers deduced that the dental drumbeat was a defense mechanism or stress response and not a method of communication, as other scientists had theorized.
"One possibility could be that the sounds are a form of a startle response (in the wild perhaps in response to an attack by a larger shark or marine mammal)," Nieder told ScienceAlert.
However, more research will be needed to see if the sharks replicate this toothy tune in the wild and under what conditions.
"This study opens up the possibility of these smaller sharks 'sounding the alarm,' " Neil Hammerschlag, president of Atlantic Shark Expeditions, who was not involved in the research, told CNN. "While we really don't know if the sound produced by the rig sharks was simply a byproduct of being handled ... it does open up some new questions, possibilities and avenues for future research."
Scientists have also yet to determine whether other shark species employ the underwater beat-boxing
Nieder, for one, believes there "is a chance other sharks are making similar noises," she said.
"This documentation could help (us) start listening to sharks, and maybe we can learn more interesting things about their ecology and lifestyle in their various ecological niches," she added.