Researchers have recorded what they believe to be the first evidence of sharks making noise, according to newly published research.
The scientists recorded New Zealand rig sharks (Musteluslenticulatus), small sharks found in coastal waters all around the country, producing clicks when handled underwater, in what they believe 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.
The researchers, led by Carolin Nieder from the Woods Hole Oceanographic Institution in the US, 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 that the forceful snapping together of the rig shark's flattened teeth is the likely source of the sound.
They base the hypothesis on the rig shark's plated teeth morphology as well as the type of noise produced, specifically its short duration (48 milliseconds) and high peak frequencies (2.4-18.5 kHz),but said that more research is needed to confirm this.
The biologists said that the purpose of the clicking sound "remains uncertain," but it may be produced "in response to disturbance or distress." Further behavioural research will be required to investigate this.
The research was published in the journal Royal Society Open Science. —dpa
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