The piranha is one of the most feared freshwater fish in the world and this is due to the violence of its attack, which can be carried out in groups or individually. However, despite her bad reputation, she is far from being a cruel and ruthless killer. She is also not a man-eater, as many imagine. “The piranha only attacks when it is hungry. And, contrary to popular belief, she doesn’t feel an uncontrollable attraction to blood. The attacks are caused mainly by objects falling into the water or unusual movements, which are interpreted as the presence of an injured or struggling animal”, says zoologist Ivan Sazima, from the State University of Campinas (Unicamp). In addition to being a skilled hunter, the piranha also feeds on dead animals and can act like a cannibal, eating companions in the pack when food is scarce. When it attacks other fish, it mainly bites off scales, fins and parts of the victim’s muscles. “Usually piranhas don’t eat the whole animal, unless they are in very large groups”, says Ivan. There are 36 different species of piranha on the planet, all found in South America alone – in Brazil, 24 species have already been identified. The largest are the black piranha (Serrasalmus rhombeus), found in the Amazon, and the São Francisco piranha (Pygocentus piraya), both measuring 40 centimeters in length. The most feared species is the cashew piranha (Pygocentrus nattereri). “It has a highly mutilating bite and when it attacks it causes serious injuries”, says Ivan.
They devour large animals, but attacks on humans are rare.
SWIMMING WITH THE ENEMY
The spotted piranha or pirambeba (Serrasalmus spilopleura) resorts to several strategies to capture its lunch. One of them is to “infiltrate” among the victims. She swims calmly alongside fish like guinea fowl until they get used to her presence. When the shoal relaxes, the pirambeba strikes!
UNDERWATER CAMOUFLAGE
Some species prefer to hunt alone, such as the catirina piranha (Serrasalmus marginatus). She likes to hide before attacking. When a fish such as a dorado approaches the catirina, it advances by surprise, biting the victim’s fins and scales.
LEGENDARY ATTACK
Attacks on bathers are rare. In general, they happen when someone approaches breeding points for species such as the spotted piranha (Serrasalmus spilopleura). Even so, there are no scientifically documented cases of fatal attacks, only popular accounts. The only proven cases of humans being devoured by piranhas occurred with people who were already dead in the water – drowned, for example.
GOOD OF MOUTH
Despite having a small mouth, the piranha has razor-sharp teeth. Its powerful jaw protrudes forward, making it easy to attack. When it bites its prey, it rips off a chunk of meat and leaves a crater-shaped mark.
PIRANHA OX 1
In the Pantanal, when a herd needs to cross a river infested with piranhas, ranchers usually sacrifice an animal to protect the rest of the herd. They wound an ox to attract the piranhas and cross the watercourse at a more distant point. The cashew piranha (Pygocentrus nattereri) is responsible for most of this type of attack in the Pantanal region
PIRANHA OX 2
The attack is done in a group, but in a disorderly way. After taking a bite, the piranha moves away, giving way to other companions. This movement of voraciously biting the victim to disfigure it is known as “eating frenzy”.