A Shark With No Voice Box Is Making Sounds at 155 Decibels

A rig shark clicked. Then another. Then eight more, each snap lasting less than a twentieth of a second and loud enough to rival a shotgun blast, coming from an animal with no voice box and no swim bladder.

Carolin Nieder, whose research focused on sharks' sensory systems, noticed that the rig sharks she was working with would start making a noise when she handled them between lab tests. Her description of the sound: "like electric sparks." The resulting paper, published in Royal Society Open Science, is believed to be the first to document sharks actively producing sound.

The species is Mustelus lenticulatus, the rig shark, a small hound shark native to New Zealand's coastal waters. The clicks were recorded roughly 30 centimeters from each shark and registered at a mean of 156 decibels, comparable in volume to a shotgun blast.

What the clicks mean is still genuinely open. The researchers propose a forceful snapping of the sharks' flattened, plate-like teeth as the source, based on tooth shape and the sound's acoustic signature. But they stop short of confirming it: direct observation of the jaws mid-click would be needed to prove it.

Whether the clicks serve any purpose is equally unsettled. It could be a startle response to handling, or it could be incidental: a stressed animal's nervous system firing rather than sending a deliberate signal. The clicks also register too high for the sharks to hear themselves, ruling out shark-to-shark chatter.

Nobody has confirmed how the sound is made, why it's made, or whether a rig shark clicks at all when nobody's holding it. A silent fish just started talking, and the silence is the only part anyone's sure of.

Read the full story at Smithsonian Magazine, March 26, 2025

Hot Take: A scientist set out to measure what sharks can hear and ended up discovering what they can say. Four hundred fifty million years of supposed silence, undone by a sound nobody was recording for.