Researchers from the Woods Hole Oceanographic Institution in the U.S. have recorded what they believed to be the first evidence of sharks making a noise.
This was according to newly published research in the Royal Society Open Science journal.
The scientists recorded New Zealand rig sharks (Mustelus lenticulatus), small sharks found in coastal waters all around the country, producing clicks when handled underwater.
The researchers, led by Carolin Nieder, found that, on average, the sharks produced significantly more clicks in the first 10 seconds of handling compared to the following 10 seconds.
They believe this is the first documented case of active sound production by a shark.
Ten juvenile rig sharks, five female and five male, were used for the study over the 11-month study.
The sounds were recorded in an experimental plastic tank set up to record the sounds.
They base the hypothesis on the rig shark’s plated teeth morphology and the type of noise produced, specifically its short duration (48 milliseconds) and high peak frequencies (2.4-18.5 kHz).
They believed that the forceful snapping together of the rig shark’s flattened teeth was the likely source of the sound.
They said that more research was needed to confirm this.
The biologists said the purpose of the clicking sound remained uncertain, but it may be produced in response to disturbance or distress.
Further behavioural research would be required to investigate this.