Researchers highlighted the piranhas' specialised jaw morphology, which allows them to attack and bite chunks out of much larger prey.
Guillermo Orti, a George Washington University Louis Weintraub Professor of Biology in the Columbian College of Arts and Sciences, and one of the authors of the paper, focuses on the evolution of fishes in general, but specialises on Amazonian fishes, to unravel evolutionary relationships based on DNA sequence data.
In 2010, Orti along with other researchers participated in an expedition to the Xingu and Iriri rivers in Amazonia to collect the data on the fish.
Piranhas' aggressive nature, relatively small size and accessible populations make them a suitable group of predatory vertebrates in which to study the evolution of extreme biting capabilities.
Even at their small body sizes, diet studies indicate that piranhas will attack and bite chunks of bony fins and flesh from prey many times larger than themselves.
In spite of their reputation, no quantitative data or empirical estimates regarding the piranhas biting abilities were available.
The paper reported the first bite-force measurements taken from wild specimens of the largest species of carnivorous piranha in the Amazon, the black piranha, and described the underlying functional morphology of the jaws that allows this creature to bite with a force more than 30 times greater than its weight.
The powerful bite is achieved primarily due to the large muscle mass of the black piranha's jaw and the efficient transmission of its large contractile forces through a highly modified jaw-closing lever, researchers said in a statement.
The study was published in journal Scientific Reports.
