October 13, 2011
Piranhas Bark When Arguing Over Dinner
The Journal of Experimental Biology released a study this week suggesting that piranhas, which have a fearsome reputation, may be more bark than bite. The river-dwelling menace may be using bark-like noises when communicating with each other when excited or confronting each other, Victoria Gill of BBC Nature is reporting.
Lead researcher of the study, Dr. Eric Parmentier, from the University of Liege, Belgium, and his colleagues placed a hydrophone into a tank of piranhas in their lab, filming the fish as they interacted.
Three distinct sounds were noticed from the fish. A bark was produced when the fish “displayed” to each other - confronting one another face to face but not engaging in violence. The other two were percussive beats, produced when the fish chased one another, and a softer croak they made when biting each other, usually over food.
The piranhas spent most of their time, however, swimming around peacefully, making no noise and engaging in no underwater conflicts. Only after hours of observation did the researchers managed to capture the behavior.
“For animals, it´s less expensive [in terms of energy] to make a lot of noise and impress the other guys, rather than fight,” explained Parmentier.
Having discovered that aggressive piranhas are very vocal, Dr. Parmentier and his team is eager to discover whether piranhas are vocal when being amorous as well.
Parmentier suspects, however, that the team will have to relocate to Brazil to answer that question. “It is difficult for the fish to reproduce in the tank, so I am sure we have to deploy hydrophones in the field to have the sounds that are produced during mating.”
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