If you think about shark noise, it might go like: duunnn dunnn… duuuunnnn duun… duuunnnnnnnn dun dun dun dun dun dun dun dun dun dun dunnnnnnnnn dunnnn.
But they actually make more of a click click click sound.
Scientists have now recorded the first ever noises made by the predators.
They do not have voice boxes or obvious mechanisms to make sounds, so were previously thought to be mute, stalking the seas silently.
But now, we know that rig sharks, which can grow to 5ft-long and mainly eat crabs, appear to make sounds intentionally.
Listen to the video below if you want to hear the noise yourself. It’s not excactly scary, but it is a bit eerie, and definitely clicky – the last thing you’d hear over the surf as the predator swam up and clamped onto your torso?
The audio was detected by scientists at the University of Auckland, in New Zealand.
Carolin Nieder was working on shark hearing for her PhD, when she noticed there was a clicking sound coming from rig sharks she was handling as part of her work.
That pondering led to more investigations, and now she is among the authors of a research study in Royal Society Open Science called ‘Evidence of active sound production by a shark’.
It tells how the elasmobranch fish family, which includes sharks, skates and rays who have skeletons made from cartilage rather than bone, were not thought to be able to make deliberate sounds.
Until recently that is; studies in 2022 also showed wild stingrays and other rays making click noises when disturbed by divers.
To record the shark sounds, scientists placed rigs in a plastic tank equipped with a hydrophone to pick up noises underwater.
How and why do they make the clicks?
Sharks have strong teeth similar to bone, and these are thought be what is making the noise.
The study says: ‘We propose that forceful snapping of flattened teeth may be the sound producing mechanism.’
The study tells how clicks occured when they were disturbed by handlers, indicating it might be due to a stress or an attempt to defend itself.
Authors said: ‘Rigs handled for 20 seconds produced significantly more clicks during the first 10 seconds than during the subsequent 10 seconds, and both in the presence and absence of body movements.
‘Rigs were not observed to produce clicks during feeding or while free-swimming in the tank.
‘This may suggest that the initial handling triggers a stress or startle response, resulting in increased click activity.
‘As rigs become accustomed to the handling, the behavioural response likely diminishes, leading to fewer clicks over time.’
Other noises that surprised us
Hearing the sound of a shark and imagining a clicky close-up is pretty interesting, but it has nothing on the sound of the sun or the sound of a black hole as it hoovers up anything getting close to it, both of which scientists have recently sonified.
It’s always fun to have an extra element of immersivity to get creative with our nightmares.
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