Giles Smith in The Times, Wed 4th July, 2007, wrote about piranhas being misunderstood, according to some recent study.
Deep down, piranhas are nervous, troubled creatures, a new study maintains. They gang together, not out of blood lust, but because they are scared of other predators. That thing they do with the unwary swimmer, where the water churns and boils with blood before, moments later, a perfectly denuded skeleton sinks to the river floor? They’re just frightened, that’s all.