Now, a report has broken that silence. Videos reveal that two species of stingraythe mangrove whipray (Urogymnus granulatus) and cowtail stingray (Pastinachus ater), both native to the Indo-West Pacificproduce striking, unmistakable clicks.
Actually, in another of the videos, the stingrays click was so boisterous, it caused the photographer to drop his camera, says Lachlan Fetterplace, a marine ecologist at the Swedish University of Agricultural Sciences who led the analysis, published recently in the journal Ecology.
While nearly one thousand species of bony fish make some type of noise, sharks, rays, and skates had, as yet, been regarded as silent outliers. And thats surprising, because scientists and divers come in the water with one of these animals at all times. (Read more about natures novel noisemakers.)
Thats sort of the strange thing, Fetterplace says. I dive a whole lot with various other species of rays, and today Im second guessing myself. MAY I have missed this?
This just shows we dont know everything, he adds. Were in the entire year 2022, and you could discover something nobody has ever seen simply by venturing out and doing observations in natural history.
So how exactly does a stingray create a sound?
Prior to the new study, the only real verified proof rays making sounds originated from a report of captive cownose rays. Published in 1970, this research recorded short, sharp clicks from the fish, but only after scientists forcefully prodded them. It wasnt until 2017 and 2018 that many of the brand new studys co-authors happened to record high-quality video while diving in Indonesia and Australia that captured the noises.
Despite the fact that the video evidence these rays make noises appears to be a slam dunk, the researchers aren’t certain the way the animals produce the sounds.
They dont have vocal cords, and theres no clear mechanism for how they take action, Fetterplace says.
In the videos, the rays spiraclestwo holes on the heads used to go water across their gillsappear to contract because the clicking sound is heard. This suggests the fish may be creating friction between your spiracles and the encompassing tissue, not unlike whenever we snap our fingers. Its also possible the rays are forming sounds by developing a vacuum, like whenever we click our tongues, Fetterplace explains.
Whatever is being conducted, chances are to be revealed soon, as other scientists already are planning studies to check out ray anatomy more closely.
What exactly are stingrays attempting to say?
For his or her research, Fetterplace and his colleagues compared the bandwidth and frequencies of the sounds to the known selection of stingray hearing. They confirmed stingrays can indeed hear these sounds, that could mean theyre a kind of communication.
Simultaneously,the scientists work showed that reef sharks and sicklefin lemon sharkspredators of both ray speciescan also hear the clicks. That suggests stingrays may issue the sounds if they sense a predator approaching as a warning, perhaps to remain from the rays’ venomous barbs.
Similarly, the quick, loud sounds may simply be considered a diversion that surprises a predator and provides the stingray an opportunity to escape. (Like the way the clicks done that underwater photographer.)
There’s another possibility, though.
When photographer and co-author Javier Delgado Esteban witnessed a wild mangrove whipray making sounds in 2018 in Geoffrey Bay, Australia, he noted another interesting behavior. After making the clicks, the juvenile was quickly joined by way of a amount of other stingrays. (Start to see the enormous stingray that set the record for worlds largest freshwater fish.)
Others would can be found in and pile around it, and all have their tails with spikes sticking up, says Fetterplace, suggesting the clicks is actually a way to contact reinforcements.
‘Really, really exciting’
Audrey Looby, a doctoral candidate and marine community ecologist at the University of Florida, recently published a scientific overview of noise-making in fish. She sifted through a lot more than 800 references dating back to to 1874 and found hardly any references to elasmobranchs, the group which includes sharks, rays, and skates.
So seeing a report come out such as this, where theres video and a thorough description of behaviors connected with those sounds, its just really, really exciting, Looby says.
Concerning how this ability went overlooked for such a long time, Looby says it may be explained by some of several factors. For example, perhaps stingrays make sounds occasionally, or only certain species can perform it, or the fish will produce noise at a particular time or season. (Read fascinating factual statements about stingrays.)
They are able to also be very difficult to study because they’re often highly mobile and elusive, says Looby.
Because many species of stingray are threatened with extinction, Fetterplace supplies a word of caution. While he and his co-authors hope their research will uncover more types of sound-producing stingrays, we dont want the general public to venture out and obtain really near a ray merely to get this type of noise.
Thats bad for the ray, he says, and its own potentially dangerous.