Piranha (other)
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A piranha (, or ; ) is any of a number of freshwater
fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...
species in the subfamily
Serrasalminae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the b ...
, of the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Serrasalmidae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the ...
, in the
order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...
Characiformes Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.; Buckup P.A.: "Relationsh ...
. These fish inhabit South American rivers,
floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...
s, lakes and reservoirs. Although often described as extremely predatory and mainly feeding on fish, their dietary habits vary extensively, and they will also take plant material, leading to their classification as
omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...
.


Etymology

The name originates from
Old Tupi Old Tupi, Ancient Tupi or Classical Tupi () is a classical Tupian language which was spoken by the indigenous Tupi people of Brazil, mostly those who inhabited coastal regions in South and Southeast Brazil. In the words of Brazilian tupinol ...
'' pirãîa'', being first attested in the 1587 treatise ' by Portuguese explorer
Gabriel Soares de Sousa Gabriel Soares de Sousa (1540–1591) was a Portuguese explorer and naturalist. A participant in Francisco Barretos Africa expeditions, he settled in the Portuguese colony of Brazil living there for seventeen years. He wrote ''Tratado Descritivo ...
. ''Piranha'' first appears in 1869 in English literature, likely borrowed from Portuguese.


Taxonomy and evolution

Piranhas belong to the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Serrasalmidae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the ...
, which includes closely related omnivorous fish such as
pacu Pacu () is a common name used to refer to several species of omnivorous South American freshwater Serrasalmidae, serrasalmid fish related to piranhas. Pacu and piranha do not have similar teeth, the main difference being jaw alignment; piranha ...
s. Traditionally, only the four
genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
''
Pristobrycon ''Pristobrycon'' is a genus of piranhas from the Orinoco and Amazon Basins, as well as rivers in the Guianas. ''Pristobrycon'' is not monophyletic. No single morphological feature has been found that completely diagnoses this genus. ''P. striol ...
'', ''
Pygocentrus ''Pygocentrus'' is a genus of the piranha family Serrasalmidae. All species are native to tropical and subtropical South America. All the species are predatory, scavengers and may form large schools. The famous red-bellied piranha, ''Pygocentrus ...
'', ''
Pygopristis ''Pygopristis denticulata'', also known as the lobetoothed piranha, is a species of piranha. It is a rare South American characiform fish found in the Orinoco River basin, rivers of the northern and eastern Guiana Shield, and tributaries of the l ...
'', and ''
Serrasalmus ''Serrasalmus'' is a genus of piranhas. They are collectively known as pirambebas; the "typical" piranhas like the piraya piranha are nowadays placed in '' Pygocentrus''. Like all piranhas, ''Serrasalmus'' are native to South America. These fis ...
'' are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed, if the piranha group is to be
monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...
, it should be restricted to ''Serrasalmus'', ''Pygocentrus'', and part of ''Pristobrycon'', or expanded to include these taxa plus ''Pygopristis'', ''
Catoprion ''Catoprion'' is a genus of serrasalmids from tropical South America, including the basins of the Amazon, Essequibo, Orinoco and Paraguay rivers. It was believed to be a monotypic In biology, a monotypic taxon is a taxonomic group (taxon) th ...
'', and ''
Pristobrycon striolatus ''Pristobrycon striolatus'' is a species of serrasalmid fish. Range and habitat ''Pristobrycon striolatus'' inhabits mainly black or acidic waters in tributaries in the Orinoco and Amazon River Basins. Description This small and beautiful ...
''. ''Pygopristis'' was found to be more closely related to ''Catoprion'' than the other three piranha genera. Under more recent taxonomic treatments, essentially all members of the subfamily
Serrasalminae The Serrasalmidae (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the b ...
within the family Serrasalmidae have "piranha" in their name, excluding the most basal members of the subfamily, ''
Metynnis ''Metynnis'' is a genus of serrasalmid fish from tropical and subtropical South America. They are herbivorous or omnivorous, and inhabit a wide range of freshwater habitats, ranging from rivers and streams (both fast- and slow-flowing), to floodp ...
'', which are referred to as " silver dollars". The total number of piranha species is unknown and contested, and new species continue to be described. Estimates range from fewer than 30 to more than 60.


Distribution

Piranhas are indigenous to the
Amazon basin The Amazon basin is the part of South America drained by the Amazon River and its tributary, tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries ...
, in the
Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...
, in rivers of the
Guianas The Guianas, also spelled Guyanas or Guayanas, are a geographical region in north-eastern South America. Strictly, the term refers to the three Guianas: Guyana, Suriname, and French Guiana, formerly British Guiana, British, Surinam (Dutch colo ...
, in the
Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...
Paraná Paraná, Paranã or Parana may refer to: Geology * Paraná Basin, a sedimentary basin in South America Places In Argentina *Paraná, Entre Ríos, a city * Paraná Department, a part of Entre Ríos Province In Brazil *Paraná (state), a state ...
, and the
São Francisco River The São Francisco River (, ) is a large Rivers of Brazil, river in Brazil. With a length of , it is the longest river that runs entirely in Brazilian territory, and the fourth longest in South America and overall in Brazil (after the Amazon R ...
systems, but there are major differences in the
species richness Species richness is the number of different species represented in an community (ecology), ecological community, landscape or region. Species richness is simply a count of species, and it does not take into account the Abundance (ecology), abunda ...
. In a review where 38–39 piranha species were recognized, 25 were from the Amazon and 16 from Orinoco, while only three were present in Paraguay–Paraná and two in São Francisco. Most species are restricted to a single river system, but some (such as the red-bellied piranha) occur in several. Many species can occur together; for example, seven are found in Caño Maporal, a stream in Venezuela.
Aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...
piranhas have been unsuccessfully introduced into parts of the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. In many cases, however, reported captures of piranhas are misidentifications of pacu (e.g., red-bellied pacu or ''
Piaractus brachypomus ''Piaractus brachypomus'' also known as the red-bellied Pacu or pirapitinga, is a large species of pacu, a close relative of piranhas and silver dollar (fish), silver dollars, in the serrasalmid family.Nico, L.; P. Fuller; and M. Neilson (22 Octo ...
'' is frequently misidentified as red-bellied piranha or ''
Pygocentrus nattereri The red-bellied piranha, also known as the red piranha (''Pygocentrus nattereri''), is a type of piranha native to South America, found in the Amazon, Paraguay, Paraná and Essequibo basins, as well as coastal rivers of northeastern Brazil.
''). Piranhas have also been discovered in the
Kaptai Lake Kaptai Lake is the largest man-made lake in Bangladesh. It is located in the Kaptai Upazila under Rangamati District of Chittagong Division. The lake was created as a result of building the Kaptai Dam on the Karnaphuli River, as part of the Karna ...
in southeast
Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...
. Research is being carried out to establish how piranhas have moved to such distant corners of the world from their original habitat. Some rogue exotic fish traders are thought to have released them in the lake to avoid being caught by antipoaching forces. Piranhas were also spotted in the
Lijiang River The Li River or Li Jiang ( zh, c=漓江, p=Lí Jiāng) is the name for the upper reaches of the Gui River in northeastern Guangxi, China. It is part of the Xijiang River system in the Pearl River basin, flowing from Xing'an County to Pingle Cou ...
in
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
.


Description


Size

Depending on the exact species, most piranhas grow to between long. A few can grow larger, with the largest living species, the red-bellied, reaching up to . There are claims of São Francisco piranhas at up to , but the largest confirmed specimens are considerably smaller. The extinct ''
Megapiranha ''Megapiranha'' is an extinct serrasalmid characin fish from the Late Miocene (8–10 million years ago) Ituzaingó Formation of Argentina, described in 2009. The type species is ''M. paranensis''.dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...
. All piranhas have a single row of sharp teeth in both jaws. The teeth are tightly packed and interlocking (via small cusps) and are used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed, and blade-like (flat in profile). The variation in the number of cusps is minor. In most species, the teeth are tricuspid with a larger middle cusp which makes the individual teeth appear markedly triangular. The exception is ''Pygopristis'', which has pentacuspid teeth and a middle cusp usually only slightly larger than the other cusps.


Biting abilities

Piranhas have one of the strongest bites found in bony fishes. Relative to body mass, the black piranha (''
Serrasalmus rhombeus The black piranha (''Serrasalmus rhombeus''), also known as the redeye piranha, white piranha, spotted piranha or yellow piranha, is a species of freshwater ray-finned fish, a piranha from the Family (biology), family Serrasalmidae. It is found in ...
'') produces one of the most forceful bites measured in vertebrates. This extremely powerful and dangerous bite is generated by large jaw muscles (adductor mandibulae) that are attached closely to the tip of the jaw, conferring the piranha with a mechanical advantage that favors force production over bite speed. Strong jaws combined with finely serrated teeth make them adept at tearing flesh.


Ecology

Piranhas vary extensively in ecology and behavior depending on exact species. Piranhas, especially the red-bellied (''Pygocentrus nattereri''), have a reputation as ferocious predators that hunt their prey in schools. Recent research, however, which "started off with the premise that they school as a means of cooperative hunting", discovered they are timid fish that schooled for protection from their own predators, such as cormorants, caimans, and dolphins. Piranhas are "basically like regular fish with large teeth". A few other species may also occur in large groups, while the remaining are solitary or found in small groups. Although popularly described as highly predatory and primarily Piscivore, feeding on fish, piranha diets vary extensively, leading to their classification as
omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...
. In addition to fish (occasionally even Cannibalism (zoology), their own species), documented food items for piranhas include other vertebrates (mammals, birds, reptiles), invertebrates (insects, crustaceans), fruits, seeds, leaves and detritus. The diet often shifts with age and size. Research on the species ''Serrasalmus'' aff. ''brandtii'' and ''Pygocentrus nattereri'' in Viana Lake in Maranhão, which is formed during the wet season when the Pindaré River (a tributary of the Mearim River) floods, has shown that they primarily feed on fish, but also eat vegetable matter. In another study of more than 250 ''Serrasalmus rhombeus'' at Ji-Paraná River, Ji-Paraná (Machado) River, 75% to 81% (depending on season) of the stomach content was fish, but about 10% was fruits or seeds. In a few species such as ''Serrasalmus serrulatus'', the dietary split may be more equal, but this is less certain as based on smaller samples: Among 24 ''S. serrulatus'' from flooded forests of Ji-Paraná (Machado) River, there were several with fish remains in their stomachs, but half contained Chewing, masticated seeds and in most of these this was the dominant item. Piranhas will often scavenge, and some species such as ''Serrasalmus elongatus'' are specialized scale-eaters, feeding primarily on scales and fins of other fish. Scale- and fin-eating is more widespread among juvenile and sub-adult piranhas. Piranhas lay their eggs in pits dug during the breeding season and swim around to protect them. Newly hatched young feed on zooplankton, and eventually move on to small fish once large enough.


Relationship with humans

Piranha teeth are often used as tools themselves (such as for carving wood or cutting hair) or to modify other tools (such as sharpening of Dart (missile), darts). This practice has been documented among several South American tribes including the Camayura and Shavante in Brazil and the Pacahuara in Bolivia. Piranhas are also popular as food, being both eaten as a subsistence catch by fishers and sold at market. However, they are often considered a nuisance by fishers because they steal bait, eat catches, damage fishing gear, and may bite when accidentally caught. Piranhas can be bought as pets in some areas, but they are illegal in many parts of the United States, and in the Philippines, where importers face six months to four years in jail, and the piranhas are destroyed to prevent proliferation. The most common aquarium piranha is ''Pygocentrus nattereri'', the red-bellied piranha. Piranhas can be bought fully grown or as young, often no larger than a thumbnail. It is important to keep ''Pygocentrus'' piranhas alone or in groups of four or more, not in pairs, since aggression among them is common, not allowing the weaker fish to survive, and is distributed more widely when kept in larger groups. It is not uncommon to find individual piranhas with one eye missing due to a previous attack.


Attacks

Although often described as extremely dangerous in the media, piranhas typically do not represent a serious risk to humans. However, attacks have occurred, especially when the piranhas are in a stressed situation such as the dense groups that may occur when the water is lower during the dry season and food is relatively scarce. Swimming near fishermen may increase the risk of attacks due to the commotion caused by struggling fish and the presence of Fishing bait, bait in the water. Splashing attracts piranhas and for this reason children are more often attacked than adults. Being in the water when already injured or otherwise incapacitated also increases the risk. Warning signs are sometimes placed at high-risk locations and beaches in such areas are sometimes protected by a barrier. Most piranha attacks on humans only result in minor injuries, typically to the feet or hands, but they are occasionally more serious and very rarely can be fatal. Near the city of Palmas, Tocantins, Palmas in Brazil, 190 piranha attacks, all involving single bites to the feet, were reported in the first half of 2007 in an artificial lake which appeared after the damming of the Tocantins River. In the state of São Paulo (state), São Paulo, a series of attacks in 2009 in the Tietê River resulted in minor injuries to 15 people. In 2011, another series of attacks at José de Freitas in the Brazilian state of Piauí resulted in 100 people being treated for bites to their toes or heels. On 25 December 2013, more than 70 bathers were attacked at Rosario in Argentina, causing injuries to their hands or feet.Mintz, Zoe (26 December 2013
Piranha Attack In Argentina Injures More Than 70, Fish Tore 'Bits Of Flesh' Off Swimmers On Christmas
ibtimes.com
In 2011, a drunk 18-year-old man was attacked and killed in Rosario del Yata, Bolivia. In 2012, a five-year-old Brazilian girl was attacked and killed by a shoal of ''P. nattereri''. In January 2015, a six-year-old girl was found dead with signs of piranha bites on part of her body after her family canoe capsized during a vacation in Monte Alegre, Brazil. Whereas fatal attacks on humans are rare, piranhas will readily feed on bodies of people that already have died, such as drowning victims.


Reputation

Various stories exist about piranhas, such as how they can skeletonize a human body or cattle in seconds. These legends refer specifically to the red-bellied piranha. Piranha solution, a dangerous mixture of sulfuric acid and hydrogen peroxide known to aggressively dissolve organic material, draws its name from these legends surrounding the piranha fish. A common falsehood is that they can be attracted by blood and are exclusively carnivores. A Brazilian legend called "piranha cattle" states that they sweep the rivers at high speed and attack the first of the cattle entering the water, allowing the rest of the group to traverse the river. These legends were dismissed through research by Hélder Queiroz and Anne Magurran and published in ''Biology Letters''.


Accounts from Theodore Roosevelt

When former US president Theodore Roosevelt visited Brazil in 1913, he went on a hunting expedition through the Amazon Rainforest. While standing on the bank of the Amazon River, he witnessed a spectacle created by local fishermen. After blocking off part of the river and starving the piranhas for several days, they pushed a cow into the water, where it was quickly torn apart and skeletonized by a school of hungry piranhas. Roosevelt later described piranhas as vicious creatures in his 1914 book ''s:Through the Brazilian Wilderness, Through the Brazilian Wilderness''.


See also

* Animal attack * Animal bite


References


External links

* Eric J. Lyman
"Piranha meat could take a bite out of what ails you"
''Houston Chronicle'', 17 July 1998
How to maintain healthy piranha in the home aquarium

"Piranha Feeding Frenzy"
National Geographic.com (2015-03-19) {{Authority control Piranhas, Fauna of the Pantanal Fish common names Fish of South America Fish of the Amazon basin Serrasalmidae