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Sharks have a well-earned reputation for being terrifying, but they’re not especially loud about it. Unlike say, a lion’s roar, there’s no signature sound that accompanies a shark attack (unless you count the Jaws theme). However a group of scientists recently found one exception to that rule: the diminutive rig shark.
A study published in the journal Royal Society Open Science presented the first known evidence of active sound production by a shark. Carolin Nieder, marine biologist at the Woods Hole Oceanographic Institution and lead author of the study, was the first to observe the phenomena, while handling rig sharks earning her doctoral degree at the University of Auckland in 2021. “At first we had no idea what it was because sharks were not supposed to make any sounds,” she told Scientific American. “I remember coming home and just thinking more and more about how weird those sounds were.”
Nieder finally got the chance to investigate those sounds years later. To do so, she and her team collected 10 rig sharks – a small species that inhabits the coastal waters of New Zealand – and placed them in tanks equipped with underwater microphones. They then handled the sharks and recorded the noises they made, a high pitched clicking sound. The sharks were observed to produce more clicks in the first 10 seconds of handling, suggesting that it was a stress or startle response from the animals.
As to how the sharks were making these sounds, the high frequencies of the clicks suggested that they were produced by forcefully snapping their plated teeth together. However, the study notes that further research is needed to confirm this hypothesis.
The next step is to determine exactly why the rig sharks make these sounds. The sounds fall outside of the range of the rig sharks’ hearing, meaning it’s probably not a form of communication between them. However, that doesn’t rule out the animals using the clicks as a warning signal to predators.
The finding also opens up the possibility that other sharks in the ocean aren’t as silent as previously believed. “I think there is a chance other sharks are making similar noises,” Nieder told CNN. “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.”
