Researchers studying red-bellied piranhas, which are among the few dangerous to humans, have discovered they routinely make distinctive barking, croaking and clicking sounds.
Using underwater microphones, scientists recorded the sounds the fish made when confronting one another.
In their findings, reported in the Journal of Experimental Biology, the team said each of the three sounds contained a different message, and that the fish often chose to intimidate their rivals rather than attack.
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The National Geographic Daily News reported that researchers already knew the piranhas, which have a voracious appetite for fresh meat, could produce sounds, but have never studied their significance.
One of the study's leading researchers, Dr Eric Parmentier, from the University of Liege, Belgium, said the team was curious to find out more.
“We wanted to know how they do this and what these sounds might mean to other fish.”
So the team placed a hydrophone into a tank of piranhas and filmed them interacting.
The BBC reported:
They recorded three distinct sounds. The first was a bark that the fish produced when they "displayed" to each other - confronting one another face to face but not fighting.
The other two were a drum-like percussive beat, which piranhas produced when they chased one another, and a softer croak they made when biting each other. These physical fights were usually over food.
Dr Parmentier said that once the scientists are able to properly understand the behavior associated with the sounds, “we might be able to listen to the sea and explain to fishermen: 'Now's not the best time to start fishing'."
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