- A new paper provides the first evidence that wild stingray species produce short, loud clicking sounds.
- While scientists still need to learn how and why stingrays make these noises, they speculate that the clicking sounds are a distress or defense signal.
- The paper documents three instances of this behavior in mangrove whiprays and cowtail stingrays, two species threatened with extinction.
In 2018, marine scientist Joni Pini-Fitzsimmons received an unusual stingray video from a colleague. It showed a mangrove whipray (Urogymnus granulatus) gliding over a reef in the Gili Islands of Indonesia, making short, loud clicks as it moved its spiracles, the respiratory openings near the animal’s eyes.
“At the time, we thought, ‘Well, that’s kind of cool,’ but it ended up on the back burner, unfortunately,” Pini-Fitzsimmons, a marine scientist and stingray expert at Macquarie University in Australia, told Mongabay.
It wasn’t until Pini-Fitzsimmons encountered a second video on Instagram of the same species making the same sound that she realized this was something worthy of attention. When she and her colleagues did some research, they found no mention of this kind of behavior in any published studies.
“To our knowledge, it’s not something that’s been recorded or published on before,” Pini-Fitzsimmons said. “I’m not entirely sure why that would be.”
She added that the clicking sounds made by the stingrays were likely some distress or defense signal, so it was possible that other researchers hadn’t gotten “close enough to them to warrant that kind of response.”
In a newly published study, Pini-Fitzsimmons and colleagues document this new evidence of sound production wild stingrays, based not only on the two videos of the mangrove whiprays, but also a video of a cowtail stingray (Pastinachus sephen) making the same noise.
“Since we put the paper out, more people have come up with examples and we’ve also found more examples,” study lead author Lachlan Fetterplace, a marine scientist at the Swedish University of Agricultural Sciences, told Mongabay. “So there’s more and more strong evidence that this is happening.”
Fetterplace added that these sounds might be “easy to miss” when diving with traditional scuba equipment, which can create a lot of underwater noise and bubbles.
One of the videos documented in the study was taken by a diver using rebreather equipment, which doesn’t produce any bubbles, and the other two were shot by snorkelers in shallower water.
But there are still many unanswered questions about these newly discovered sounds. The researchers say they need to understand the exact way in which the stingrays are making these sounds, the reasons for their calls, and whether related species demonstrate similar behaviors.
Simon Hilbourne, a marine biologist at the ray-and-shark research organization Manta Trust, who was not involved in the study, said the findings were “surprising.”
“Noise production from sharks and rays is pretty much unheard of in published literature,” Hilbourne told Mongabay in an email. “However, we still don’t know all that much about sharks and rays, so to have unusual or surprising things like this pop up should be expected. It’s great to see the narrative of ‘sharks and rays don’t produce sound’ being challenged.”
Hilbourne said there’s a growing amount of anecdotal evidence that manta rays (Mobula spp.), which are related to stingrays, also make similar noises.
“[T]hese reports tend to be associated with mantas that got spooked and part of a flight reaction,” Hilbourne said. “One of these instances was with an oceanic manta ray [M. birostris] off the coast of Sri Lanka where photographer Tony Wu described the noise as a ‘brief, punctuated, scratchy, high-pitched screech.’ The Manta Trust has started compiling such reports as although they are incredibly rare, they do exist.”
Fetterplace said he and his colleagues plan to undertake further research on stingray sound production, and want to hear from others who may have documented these behaviors.
“We want more examples, but we don’t want people specifically going up to rays and [trying to] get aggression from them, because like all wild animals, they may defend themselves if you’re harassing them,” he said. “We want examples that are incidental or from research that is specifically looking for it.”
Pini-Fitzsimmons said she hopes this new evidence of sound production will raise awareness about rays, many of which are under threat from human pressures.
Mangrove whiprays are classified as vulnerable to extinction on the IUCN Red List, and cowtail stingrays as near threatened.
“Rays and sharks are globally threatened,” Pini-Fitzsimmons said. “One of the issues that we’ve got is that we know so little about them, and so discoveries like this helps to fuel our understanding … and gets people excited about them.”
She added the findings show how little we still know about life underwater, even when it comes to common species like stingrays.
“We’re only now learning that they can effectively talk,” she said. “That’s one of the most exciting things.”
Banner image: Mangrove whiprays (Urogymnus granulatus). Image courtesy of J. Javier Delgado Esteban.
Fetterplace, L. C., Delgado Esteban, J. J., Pini‐Fitzsimmons, J., Gaskell, J., & Wueringer, B. E. (2022). Evidence of sound production in wild stingrays. Ecology. doi:10.1002/ecy.3812
Elizabeth Claire Alberts is a staff writer for Mongabay. Follow her on Twitter @ECAlberts.
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