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Piranha Facts & Worksheets

A common name for different South America, freshwater, tropical fish under the order Characiformes, a piranha is notorious for its pointed, razor-sharp teeth in a pronounced underbite.

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A common name for different South America, freshwater, tropical fish under the order Characiformes, a piranha is notorious for its pointed, razor-sharp teeth in a pronounced underbite. Distinguished for its aggressive appetite for meat and flesh, a piranha has significant ecological roles in food chains, preying upon fish, while being eaten by larger fish, birds, and mammals.

See the fact file below for more information on the piranha or alternatively, you can download our 21-page Piranha worksheet pack to utilise within the classroom or home environment.

Key Facts & Information

TAXONOMY

  • The Serrasalminae subfamily, of the Characidae family, consists of the piranhas, pacus, and silver dollars. Identified as characins, members of this family inhabit Central and South America, southern North America, and Africa, and are defined by their well-developed teeth. Fish under this classification are also characterized by the presence of a pelvic fin with five to twelve rays, a small adipose fin between the dorsal and caudal fin, and a body covered with scales.
  • However, the Characidae family has encountered some taxonomic changes. While the larger piranhas, pacus, and silver dollars have been originally grouped in this family, some researchers now classify them in their own related family, the Serrasalmidae.
  • Pacu and piranha are differentiated from each other by their teeth and jaw alignments. Generally, piranhas have pointed, razor-sharp teeth in a prominent underbite, whereas pacus have square, straight teeth in a less noticeable underbite, or somewhat of a overbite.
  • Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis, and Serrasalmus are classified as true piranhas because of their specialized teeth. However, recent studies suggested that if the piranha group is to be monophyletic, it should just be limited to Serrasalmus, Pygocentrus, and portions of Pristobrycon, or expanded to include these taxa, together with the Pygopristis, Catoprion, and Pristobrycon striolatus. The genera Pygopristis was discovered to have been more correlated to Catoprion compared to the other piranha genera.
  • The wimple piranha, Catoprion, was not originally labelled a true piranha; the shape of its teeth and the presence of two rows of teeth on the upper jaw makes it unique from other piranha genera.
  • There are about 24 piranha species, and new species continue to emerge. In 1988, it was suggested that more than half of the estimated 60 nominal species of piranhas at that time were valid. In 2003, one author proposed a total of 38 or 39 species, although the credibility of some taxa still remains debatable.

ANATOMY AND PHYSIOLOGY

  • Piranhas are generally six to ten inches long, although there are some species that reach 24 inches in length.
  • The Serrasalmus, Pristobrycon, Pygocentrus, and Pygopristis are easily distinguishable for their unique dentitio. All piranhas have a single row of razor-sharp teeth in both jaws; the teeth, which are used for rapid puncture and shearing, are crowded with interlocking brains.
  • There is a slight difference in the number of cusps; in most species, the teeth are tricuspid with a bigger middle cusp that causes the individual teeth to look triangular in shape. The Pygopristis is an exception; it has pentacuspid teeth and a middle cusp that is usually somewhat bigger than the other cusps.

DISTRIBUTION

  • Piranhas only swim in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paraná river basin, like the Pantanal, and in the São Francisco River systems.
  • Some piranha species are widely distributed across geographic ranges, swimming in more than one of the major basins mentioned.
  • They have also been introduced in some regions of the United States, even being sporadically seen in the Potomac River, but these fish do not survive the cold winters of that area.

ECOLOGY

  • Piranhas play an important role in their natural habitats. Although they are extremely restricted to lowland drainages, they are extensive and thrive in different habitats within both stagnant and running waters.
  • They are both predators and scavengers; piranhas affect the local distribution and composition of fish assemblages. Specifically known piranha species feed on large quantities of seeds, but compared to the related Colossoma and Piaractus, plant-eating piranhas seem to chew and destroy all seeds and do not act as dispersers.
  • Piranhas are labelled as vicious fish species, hunting in large groups. This impression was created from the past belief that piranhas formed groups for hunting purposes. However, recent studies show that this behavior is actually a defense mechanism against their natural predators, such as river dolphins, caimans, and giant pirarucu.
  • Research on Serrasalmus aff. Brandtii and Pygocentrus nattereri in Viana Lake suggested they feed on vegetable matter at some stages of their life; hence, they are not strictly considered carnivorous.

RELATIONSHIP TO HUMANS

  • Piranhas are a source of food in regions in which they swim. Some of them have mythical reputations as an aphrodisiac and a cure for conditions dealing with fertility, virility, and even baldness.
  • Their teeth are also used by locals to craft tools and weapons.
  • There are instances when piranhas bite and sometimes injure bathers and swimmers, but serious attacks are uncommon and the threat to humans are just exaggerated. However, piranhas are seen as an annoyance to commercial and sport fishers because they steal bait, butcher catch, and destroy nets and other fishing apparatus, and may bite when handled.
  • There are some piranha species that appear in aquarium trade. They are bought as pets in some regions; however, they are illegal in some parts of the United States.

Piranha Worksheets

This is a fantastic bundle which includes everything you need to know about the piranha across 21 in-depth pages. These are ready-to-use Piranha worksheets that are perfect for teaching students about the piranha which is notorious for its pointed, razor-sharp teeth in a pronounced underbite. Distinguished for its aggressive appetite for meat and flesh, a piranha has significant ecological roles in food chains, preying upon fish, while being eaten by larger fish, birds, and mammals.

Complete List Of Included Worksheets

  • Piranha Facts
  • Piranha Overview
  • Piranha Anatomy
  • Think Tank
  • Piranha Species
  • Piranha Quiz
  • Edible Piranhas?
  • Predator Comparison
  • Piranha Wiki
  • Piranha Poem
  • Relationship with Humans

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Link will appear as Piranha Facts & Worksheets: https://kidskonnect.com - KidsKonnect, February 17, 2021

Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

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