Relax, It’s Only a Piranha

"They will snap a finger off a hand incautiously trailed in the water," Teddy Roosevelt once wrote about the legendary toothed fishes of South America. "They will rend and devour alive any wounded man or beast."

"Piranhas," TR determined, "are the most ferocious fish in the world." His estimation created a mystique and fear of piranhas in the West that has only grown more fierce over the years. But according to recent research — and the firsthand reports of daring author Richard Conniff — most piranhas are surprisingly harmless.

Like most men, Conniff writes, the vast majority of piranhas "lead lives of quiet desperation. Instead of swarming over their victims in a tumult of flashing teeth, piranhas mostly lurked and stalked and even disguised themselves as other species to snatch their food on the sly." Researchers have found, in fact, that most piranhas prefer to feed on the tail fins or scales of prey fish rather than devour the critters whole.

Conniff headed off to South America, determined to find that there was more to the piranha than a "mere petting zoo animal." In the rivers of Venezuela and Peru, where the few dangerous species of piranha occur in great numbers, he found what he was looking for — the dread red-bellied piranhas. Time after time, he heard stories of flesh-rending assaults by these piranhas — and saw the piranhian feeding frenzies, in areas where fishermen chummed the waters with fresh meat.

But in calmer waters, the locals — and Conniff himself — felt perfectly comfortable swimming with the fish known in some regions as "donkey castrators." Nevertheless, Conniff admits, "there is no way on earth" he "will ever skinny dip" among them.

Richard Conniff | READ MORE

Richard Conniff, a Smithsonian contributor since 1982, is the author of seven books about human and animal behavior.