The piranha, formidable predatory fish of South American rivers

While many species of piranhas are herbivores, others are formidable predators armed with powerful jaws and teeth. sharp like razors. Meeting with the terror of the waters Amazonian.

Two kinds of piranhas

Behind the term piranha are 80 species approximately of freshwater fish living in the rivers of South America. All belonging to the family of Characidae (or Characins) and the Serrasalminés subfamily, piranhas are divided into 2 genres :

1 – Serrasalmus. These piranhas exhibit, among other features, sharp teeth and a rhomboid body. Most are herbivores;

2 – Pygocentrus Pygocentrus. These predators form immense schools of one hundred to several thousand individuals. Three species are recognized as potentially dangerous for humans during the dry season:

  • Pygocentrus nattereri (red piranha or red-bellied piranha) throughout the Amazon basin;
  • Pygocentrus cariba (black-eared piranha) in the Orinoco;
  • The Pygocentrus piraya (black-tailed piranha) in the Rio San Francisco river in Brazil.

The fierce allure of the piranha

The fish of the Serrasalminés subfamily present a morphological homogeneity. Their body round is somewhat laterally compressed. At the top of the skull, a bony crest supports the dorsal carina. The latter is reinforced by a solid row of large scales with sharp points rear facing. The thin and muscular tail allows the piranha to cut through the water with force and speed. While the general shape of the genera Pygocentrus and Serrasalmus remains similar, the coats may differ in color. Greater width of the head and body gives some a more stocky that others.

The most famous red piranha

The piranha red is undoubtedly the best known because one of the most dangerous of all. It owes its name to its belly which reddens during reproduction. This fish has two large eyes placed very high on the head. Its fierce appearance is due to a marked prognathism (jaws thrown forward) and its teeth triangular sharp, capable of slicing a piece of flesh with incredible sharpness. It displays an average length of 15 to 25 cm but some specimens can reach 50 cm and weigh 4 kg.

The piranha, freshwater fish

All species of piranhas evolve in the regions tropical from South and Central America except Chile. These fish inhabit rivers, streams, still or stagnant waters and hot. Their presence is particularly important throughout the Amazon, the Orinoco, the rivers of the Guyanas, the Gran Chaco, the Paraná river, the Uruguay river and the Río de la Plata. In general, piranhas live alone but can cluster together when food becomes scarce.

The piranha, drawn to blood

The species carnivorous consume fish and other aquatic animals that they spot by their movements in the water. They also feed on insects, molluscs, rodents or snakes. One hunting tactic is to gather in massive schools to attack prey by amputant its caudal fins and deprive it of any chance of flight. The triangular teeth of the red piranha cut like razor blades, its victim is thus devoured entirely, bone and head included, in a few seconds. Attracted by the smell of blood, the red piranha can attack larger animals if they are sick or wounded. By eating the weakest animals, it prevents the spread of diseases that can generate a source of pollution. Namely, many piranhas are herbivores. The Pacu species, for example, essentially composes its menu with fruits and seeds.

The piranha, fierce in the dry season

Piranhas are particularly aggressive in times of drought when the struggle for survival is fierce. Trapped and gathered in large numbers in dry water points, they direct their first attacks towards the most vulnerable individuals. fragile of their group. At this time of year, hungry fish devour anything within their reach including large prey such as fish. mammals who come to quench their thirst at the water’s edge. Man is no exception like fishermen or bathers. For the record, in 2013, more than 60 people were injured following the attack on a school of piranhas, in a river in Argentina. The victims suffered bites limbs and had severed fingers and toes.

The vulnerable piranha according to the seasons

Thanks to their formidable jaws, piranhas have few enemies. It is in the dry season that they are the most vulnerable. Stuck in water which becomes scarce by evaporation and infiltration, they rise regularly to the surface to absorb water.oxygen and fall prey to raptors and other birds (heron), but also caimans and other hungry predators. The piranha can also be devoured by its own congeners. The species is classified in minor concern by the International Union for the Conservation of Nature (IUCN). Its longevity is 12 years in the wild and up to 20 years in aquarium.