The Piranha May Be Getting a Bad Rap : Fish: The name is synonymous with flesh-eating ferocity, but the Amazon dweller may not be as bloodthirsty as people think.

--With a final dizzying twist, our dugout canoe squirted through the rapids and into a quiet lagoon. Safe at last, I thought.

We were on the Yarapa River, a meandering tributary of the Amazon, on the first leg of an expedition into the deep jungle. I sagged back in my seat, sweaty and exhausted. One hand flopped over the gunwale and trailed in the tea-colored water.

“I wouldn’t do that,” said the guide, Ricardo Ruiz. He held up his own left thumb, a nasty slice near its tip.

“Piranha,” he said.

Piranha. The Guarani Indian word for the fierce little fish that inhabits much of South America has become an English synonym for ferocity and greed. It is the fish with an attitude.

While not entirely dispelling this image, recent research has shown piranhas may not be as bloodthirsty as people think. Some piranhas even become vegetarians at certain times of the year.

Stories of piranha violence have thrilled and horrified people beyond South America since the 16th Century, when the first Spanish explorers began sending back reports of strange wildlife.The piranhas reputed attraction to blood lends a gruesome quality to many accounts.

Famed British army surveyor Percy Fawcett tells of a Bolivian soldier who fell from his patrol boat into a piranha-infested pool and found that his heavy boots prevented him from climbing back in. After much screaming, the man became quiet. When rescuers finally reached him and pried his hands from the gunwale, they found his entire lower torso had been stripped to the bone.

They theorized that piranhas had been attracted by his red trousers.

“Any of it is possible,” says University of Florida zoologist Leo G. Nico, referring to lurid accounts he has heard of piranha attacks. “They have the potential to do that, with their teeth and strong jaws.”

But Nico and other scientists who study piranhas say the fish’s ugly reputation is largely undeserved.

“I don’t disregard occasional stories of attack,” says Nico. “But I think they are really rare. I compare piranhas with dogs. They have the potential to do a lot of damage, but in most cases they never do.”

Unlike dogs, however, piranhas have been little studied and are poorly understood. Even the number of piranha species is disputed. Antonio Machado-Allison of the University of Venezuela and William Fink of the University of Michigan have counted some 30 species and are finding still more.

Adult piranhas range in length from 9 inches to 20 inches. Like sharks and billy goats, they aren’t discriminating diners. Researchers have found in their stomachs fragments of birds, snakes, small mammals and even a young caiman--a South American alligator.

Piranhas do attack live animals, however. They have good vision, a well-developed sense of smell, and a system of pores along their body that allows them to detect distant disturbances in water and pinpoint their direction.

But Nico says most humans are wounded after piranhas have been hooked by fishermen and brought aboard boats. Fried piranha is prized in many parts of South America for its delicate, flaky white flesh.

“If we were keeping score, piranhas could say that human-infested shores are among the most dangerous in the world,” Nico says. “We bite them more than they bite us.”