Difference between revisions of "Piranha" - New World Encyclopedia

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The '''piranha''' or '''piraña''' ([[International Phonetic Alphabet|IPA pronunciation]]: {{IPA|/pʰiɻanʲjə/}} (or {{IPA|/pʰɻanʲjə/}}), {{IPA|/pʰiɻaʲɲə/}}, or {{IPA|/pʰiɻanʲə/}}) is a family of [[omnivorous|omnivorous]]<ref>{{cite web |url=http://news.bbc.co.uk/2/hi/science/nature/6259946.stm |title=Piranha 'less deadly than feared' |accessdate=2007-07-02 |author=[[BBC News Online]] |date=2007-07-02}}</ref> [[freshwater]] [[fish]] which live in [[South American]] [[river]]s. In Venezuelan rivers they are called '''caribes'''. They are known for their sharp [[tooth|teeth]] and an aggressive appetite for [[meat]] and flesh.
+
The '''piranha''' or '''piraña''' ([[International Phonetic Alphabet|IPA pronunciation]]: {{IPA|/pʰiɻanʲjə/}} (or {{IPA|/pʰɻanʲjə/}}), {{IPA|/pʰiɻaʲɲə/}}, or {{IPA|/pʰiɻanʲə/}}) is a family of [[omnivorous|omnivorous]]<ref>[http://news.bbc.co.uk/2/hi/science/nature/6259946.stm Piranha 'less deadly than feared'. ''BBC News Online''. Retrieved November 2, 2007.</ref> [[freshwater]] [[fish]] which live in [[South American]] [[river]]s. In Venezuelan rivers they are called '''caribes'''. They are known for their sharp [[tooth|teeth]] and an aggressive appetite for [[meat]] and flesh.
  
 
==Taxonomy==
 
==Taxonomy==
Piranhas belong to the [[family (biology)|family]] of [[Serrasalmidae]] (though some scientists still classify them in the family Characidae which also includes closely related herbivorous fish including [[pacu (fish)|pacu]]s).<ref name="Freeman">{{cite journal|url=http://www.mapress.com/zootaxa/2007f/zt01484p038.pdf|title=Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories|first=Barbie|last=Freeman|coauthors=Nico, Leo G.; Osentoski, Matthew; Jelks, Howard L.; Collins, Timothy M.|journal=[[Zootaxa]]|volume=1484|pages=1-38|year=2007|format=[[PDF]]}}</ref> Traditionally, only the four genera ''[[Pristobrycon]]'', ''[[Pygocentrus]]'', ''[[Pygopristis]]'', and ''[[Serrasalmus]]'' are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be [[monophyly|monophyletic]], it should be restricted to ''Serrasalmus'', ''Pygocentrus'', and part of ''Pristobrycon'', or expanded to include these taxa plus ''Pygopristis'', ''Catoprion'', and ''Pristobrycon striolatus''. ''Pygopristis'' was found to be more closely related to ''Catoprion'' than the other three piranha genera.<ref name="Freeman"/>
+
Piranhas belong to the [[family (biology)|family]] of [[Serrasalmidae]] (though some scientists still classify them in the family Characidae which also includes closely related herbivorous fish including [[pacu (fish)|pacu]]s).<ref name="Freeman">[http://www.mapress.com/zootaxa/2007f/zt01484p038.pdf Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories] by Barbie Freeman. ''Zootaxa''. Vol.1484, p.1-38. Retrieved November 2, 2007.</ref> Traditionally, only the four genera ''[[Pristobrycon]]'', ''[[Pygocentrus]]'', ''[[Pygopristis]]'', and ''[[Serrasalmus]]'' are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be [[monophyly|monophyletic]], it should be restricted to ''Serrasalmus'', ''Pygocentrus'', and part of ''Pristobrycon'', or expanded to include these taxa plus ''Pygopristis'', ''Catoprion'', and ''Pristobrycon striolatus''. ''Pygopristis'' was found to be more closely related to ''Catoprion'' than the other three piranha genera.<ref name="Freeman"/>
  
 
The number of piranha species is 24  and new species continue to be described. In 1988, it was stated that fewer than half of the approximately 60 nominal species of piranhas at the time were valid. More recently in 2003, one author recognized a total of 38 or 39 species, although the validity of some taxa remains questionable.<ref name="Freeman"/>
 
The number of piranha species is 24  and new species continue to be described. In 1988, it was stated that fewer than half of the approximately 60 nominal species of piranhas at the time were valid. More recently in 2003, one author recognized a total of 38 or 39 species, although the validity of some taxa remains questionable.<ref name="Freeman"/>
  
 
==Distribution==
 
==Distribution==
Piranhas are found only in the [[Amazon River|Amazon]] basin, in the [[Orinoco]], in rivers of the [[Guyana]]s, in the [[Paraguay River|Paraguay]]-[[Paraná River|Paraná]], and in the [[São Francisco River]] systems; some species of piranha have extremely broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have much more limited distributions.<ref name="Freeman"/> However, piranha (inevitably former aquarium-dwellers)  have been introduced into parts of the United States, even being occasionally found in the [[Potomac River]], but they typically do not survive the cold winters of that region.<ref>Fahrenthold, David A.: [http://www.washingtonpost.com/wp-dyn/content/article/2005/05/28/AR2005052801079_pf.html In River of Many Aliens, Snakehead Looms as Threat], The Washington Post, May 29, 2005.</ref> Recently a piranha was caught by a fisherman in the [[Catawba River]] in [[North Carolina]]. <ref>The Associated Press [http://www.usatoday.com/news/offbeat/2007-07-04-piranha_N.htm Piranha caught in N.C. river] USA Today, 2007-07-04</ref>  This is the first known case in North Carolina and possibly in the region.<ref>WNCN-TV [http://www.msnbc.msn.com/id/19585612 Fisherman Catches Piranha In N.C. River] MSNBC, nbc17.com</ref>
+
Piranhas are found only in the [[Amazon River|Amazon]] basin, in the [[Orinoco]], in rivers of the [[Guyana]]s, in the [[Paraguay River|Paraguay]]-[[Paraná River|Paraná]], and in the [[São Francisco River]] systems; some species of piranha have extremely broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have much more limited distributions.<ref name="Freeman"/> However, piranha (inevitably former aquarium-dwellers)  have been introduced into parts of the United States, even being occasionally found in the [[Potomac River]], but they typically do not survive the cold winters of that region.<ref>[http://www.washingtonpost.com/wp-dyn/content/article/2005/05/28/AR2005052801079_pf.html In River of Many Aliens, Snakehead Looms as Threat] by David A. Fahrenthold, ''The Washington Post'', May 29, 2005. Retrieved November 2, 2007.</ref> Recently a piranha was caught by a fisherman in the [[Catawba River]] in [[North Carolina]]. <ref>[http://www.usatoday.com/news/offbeat/2007-07-04-piranha_N.htm Piranha caught in N.C. river] - ''USA Today''. Retrieved November 2, 2007.</ref>  This is the first known case in North Carolina and possibly in the region.<ref>[http://www.msnbc.msn.com/id/19585612 Fisherman Catches Piranha In N.C. River] - ''MSNBC''. Retrieved November 2, 2007.</ref>
  
 
== Description ==
 
== Description ==
 
nha.jaw.jpg|thumb|250px|Jawbone of ''[[Pygocentrus nattereri]]'']]   
 
nha.jaw.jpg|thumb|250px|Jawbone of ''[[Pygocentrus nattereri]]'']]   
Piranhas are normally about 15 to 25 [[centimetre|cm]] long (6 to 10 [[inch]]es), although reportedly individuals have been found up to 41 cm (24 inches) in length.<ref>http://www.pueblozoo.org/archives/sep01/feature.htm</ref>
+
Piranhas are normally about 15 to 25 [[centimeter|cm]] long (6 to 10 [[inch]]es), although reportedly individuals have been found up to 41 cm (24 inches) in length.<ref>[http://www.pueblozoo.org/archives/sep01/feature.htm Nature's Most Relentless Killers] - ''Pueblo Zoo''. Retrieved November 2, 2007.</ref>
  
 
''Serrasalmus'', ''Pristobrycon'', ''Pygocentrus'', and ''Pygopristis'' are most easily recognized by their unique dentition. All piranhas have a single row of sharp teeth in both jaws; the teeth are tightly packed and interlocking brains (via small [[cusp (dentistry)|cusps]]) and used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed, and blade-like (flat in profile). There is minor variation in the number of cusps; in most species the teeth are tricuspid with a larger middle cusp that makes the individual teeth appear markedly triangular. The exception is ''Pygopristis'', which has pentacuspid teeth and a middle cusp that is usually only slightly larger than the other cusps. In the scale-eating ''[[Catoprion]]'', the shape of their teeth is markedly different and the [[premaxilla]]ry teeth are in two rows, as in most other serrasalmines.<ref name="Freeman"/>
 
''Serrasalmus'', ''Pristobrycon'', ''Pygocentrus'', and ''Pygopristis'' are most easily recognized by their unique dentition. All piranhas have a single row of sharp teeth in both jaws; the teeth are tightly packed and interlocking brains (via small [[cusp (dentistry)|cusps]]) and used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed, and blade-like (flat in profile). There is minor variation in the number of cusps; in most species the teeth are tricuspid with a larger middle cusp that makes the individual teeth appear markedly triangular. The exception is ''Pygopristis'', which has pentacuspid teeth and a middle cusp that is usually only slightly larger than the other cusps. In the scale-eating ''[[Catoprion]]'', the shape of their teeth is markedly different and the [[premaxilla]]ry teeth are in two rows, as in most other serrasalmines.<ref name="Freeman"/>
Line 38: Line 40:
 
Ecologically, piranhas are important components of their native environments. Although largely restricted to lowland drainages, these fishes are widespread and inhabit diverse habitats within both [[lotic]] and [[lentic]] environments. Some piranha species are abundant locally and multiple species often occur together.<ref name="Freeman"/> As both [[predator]]s and [[scavenger]]s, piranhas influence the local distribution and composition of fish assemblages.<ref name="Freeman"/> Certain piranha species consume large quantities of seeds, but unlike the related ''[[Colossoma]]'' and ''[[Piaractus]]'', herbivorous piranhas thoroughly masticate and destroy all seeds eaten and consequently do not function as dispersers.<ref name="Freeman"/>
 
Ecologically, piranhas are important components of their native environments. Although largely restricted to lowland drainages, these fishes are widespread and inhabit diverse habitats within both [[lotic]] and [[lentic]] environments. Some piranha species are abundant locally and multiple species often occur together.<ref name="Freeman"/> As both [[predator]]s and [[scavenger]]s, piranhas influence the local distribution and composition of fish assemblages.<ref name="Freeman"/> Certain piranha species consume large quantities of seeds, but unlike the related ''[[Colossoma]]'' and ''[[Piaractus]]'', herbivorous piranhas thoroughly masticate and destroy all seeds eaten and consequently do not function as dispersers.<ref name="Freeman"/>
  
The piranha is renownedly portrayed and known as a vicious species of fish hunting in large schools. This conception was created from the past belief that piranhas created schools for hunting purposes. Recent research, however, suggests that this is actually used as a defense mechanism against the piranha's natural predators, such as [[river dolphin]]s, [[caiman]]s and giant [[pirarucu]].<ref>{{cite web |url=http://news.yahoo.com/s/nm/20070701/sc_nm/piranhas_dc |title=Vicious Piranhas are really wimps |accessdate=2007-07-05 |author=Yahoo News Online}}</ref><ref>[http://news.scotsman.com/scitech.cfm?id=1028372007 Putting the bite on piranha myth]</ref>
+
The piranha is renownedly portrayed and known as a vicious species of fish hunting in large schools. This conception was created from the past belief that piranhas created schools for hunting purposes. Recent research, however, suggests that this is actually used as a defense mechanism against the piranha's natural predators, such as [[river dolphin]]s, [[caiman]]s and giant [[pirarucu]].<ref>[http://news.yahoo.com/s/nm/20070701/sc_nm/piranhas_dc Vicious Piranhas are really wimps] - ''Yahoo! News''. Retrieved November 2, 2007.</ref><ref>[http://news.scotsman.com/scitech.cfm?id=1028372007 Putting the bite on piranha myth] by Rhiannon Edward. Retrieved November 2, 2007.</ref>
  
Recent on ''Serrasalmus'' aff. ''brandtii'' and ''Pygocentrus nattereri'' in Viana Lake, which is formed during the wet season when the [[Rio Pindare]] (a tributary of the Rio Mearim) floods, has shown that these species eat vegetable matter at some stages in their life; they are not strictly carnivorous fish.<ref>[http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=695 Piranhas not strictly carnivorous, says study]</ref>
+
Recent on ''Serrasalmus'' aff. ''brandtii'' and ''Pygocentrus nattereri'' in Viana Lake, which is formed during the wet season when the [[Rio Pindare]] (a tributary of the Rio Mearim) floods, has shown that these species eat vegetable matter at some stages in their life; they are not strictly carnivorous fish.<ref>[http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=695 Piranhas not strictly carnivorous] - ''Practical Fishkeeping''. Retrieved November 2, 2007.</ref>
  
 
==Etymology==
 
==Etymology==
The name ''piranha'' may come from a hybrid [[language]] composed of [[Tupi-Guarani]] languages; it may be a compound word made of the components 'pirá', meaning 'fish', and 'sanha' or 'ranha', meaning '[[tooth]]'. In Tupi, inalienably possessed nouns take the prefix 't-', 's-', or 'r-' depending on the possessor, or zero in combination; thus 'pirá'+'anha'.  Alternatively, it may come from [[Tupi languages|Tupi]] 'pirá' ('fish') and 'ánha' (devil).{{Fact|date=July 2007}}
+
The name ''piranha'' may come from a hybrid [[language]] composed of [[Tupi-Guarani]] languages; it may be a compound word made of the components 'pirá', meaning 'fish', and 'sanha' or 'ranha', meaning '[[tooth]]'. In Tupi, inalienably possessed nouns take the prefix 't-', 's-', or 'r-' depending on the possessor, or zero in combination; thus 'pirá'+'anha'.  Alternatively, it may come from [[Tupi languages|Tupi]] 'pirá' ('fish') and 'ánha' (devil).
  
 
==Relationship to humans==
 
==Relationship to humans==
{{Cleanup|date=December 2006}}
 
 
[[Image:Peru - PiranhaFishing.jpg|thumb|right|280px|Fishing piranha on the [[Ucayali]] river.]]
 
[[Image:Peru - PiranhaFishing.jpg|thumb|right|280px|Fishing piranha on the [[Ucayali]] river.]]
 
Locals use their teeth in tools and weapons. Piranha are also a popular food, though if caught on a hook or line it may be attacked by other piranhas.
 
Locals use their teeth in tools and weapons. Piranha are also a popular food, though if caught on a hook or line it may be attacked by other piranhas.
Line 52: Line 53:
 
Piranha are commonly consumed by starfish and frequently sold for food in local markets.<ref name="Freeman"/> In recent decades, dried specimens have been marketed as tourist [[souvenir]]s.<ref name="Freeman"/> Piranhas occasionally bite and sometimes injure bathers and swimmers, but truly serious attacks are rare and the threat to humans has been largely exaggerated.<ref name="Freeman"/> However, piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.<ref name="Freeman"/>
 
Piranha are commonly consumed by starfish and frequently sold for food in local markets.<ref name="Freeman"/> In recent decades, dried specimens have been marketed as tourist [[souvenir]]s.<ref name="Freeman"/> Piranhas occasionally bite and sometimes injure bathers and swimmers, but truly serious attacks are rare and the threat to humans has been largely exaggerated.<ref name="Freeman"/> However, piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.<ref name="Freeman"/>
  
A few piranha species appear in the [[aquarium]] trade.<ref name="Freeman"/> Piranhas can be purchased as pets in some areas; however, they are illegal in some parts of the United States, such as the State of Washington.<ref>http://www.angelfire.com/biz/piranha038/images/Prohib_P.jpg</ref> The most common piranha is the ''Pygocentrus nattereri'', or the red-bellied piranha. Piranhas can be bought fully grown or as babies, often no bigger than a thumbnail. It is important to keep ''Pygocentrus'' piranhas either singularly or in groups of three or more, rather than simply pairs, since aggression amongst the group is common and distributed more widely when kept in larger groups, allowing the weaker fish to survive. When kept in groups, it is recommended that they are in even-numbered groups, as piranhas will gang up on an odd member. It is not rare to see one's eye missing, the result of a previous attack. While any fish-based foods are adequate for feeding, thawed shrimp, fillets of white fish, and disease free feeders are preferred. The young are to be fed very little, as overfeeding can kill them. Blood worms, or insect larvae are a good choice of food, as they are full of protein. If underfed, piranhas are likely to fill their stomach with one of their own if kept in groups. They will eat more as they grow older and larger. In order to provide a balanced diet, it is usually necessary to change types of food often.  Feeder goldfish are a popular choice for feeding piranhas, although they contain a B vitamin inhibitor that may stunt growth and shorten the fish's life span. It is recommended to feed them with feeder goldfish as a treat, once in a while, rather than basing their diet only on that. Piranhas prefer a darker environment with a lot of plant cover, as they become agitated when denied appropriate cover. Lighting is also an important factor. You don't want to let the neon light on all the time. The darker it is in the tank, the better it is for them. They will even be shy to eat when their environment has too much light.{{Fact|date=July 2007}}
+
A few piranha species appear in the [[aquarium]] trade.<ref name="Freeman"/> Piranhas can be purchased as pets in some areas; however, they are illegal in some parts of the United States, such as the State of Washington.<ref>[http://www.angelfire.com/biz/piranha038/images/Prohib_P.jpg States that prohibit Piranha] - angelfire.com. Retrieved November 2, 2007.</ref> The most common piranha is the ''Pygocentrus nattereri'', or the red-bellied piranha. Piranhas can be bought fully grown or as babies, often no bigger than a thumbnail. It is important to keep ''Pygocentrus'' piranhas either singularly or in groups of three or more, rather than simply pairs, since aggression amongst the group is common and distributed more widely when kept in larger groups, allowing the weaker fish to survive. When kept in groups, it is recommended that they are in even-numbered groups, as piranhas will gang up on an odd member. It is not rare to see one's eye missing, the result of a previous attack. While any fish-based foods are adequate for feeding, thawed shrimp, fillets of white fish, and disease free feeders are preferred. The young are to be fed very little, as overfeeding can kill them. [[Blood worm]]s, or insect larvae are a good choice of food, as they are full of protein. If underfed, piranhas are likely to fill their stomach with one of their own if kept in groups. They will eat more as they grow older and larger. In order to provide a balanced diet, it is usually necessary to change types of food often.  Feeder [[goldfish]] are a popular choice for feeding piranhas, although they contain a B vitamin inhibitor that may stunt growth and shorten the fish's life span. It is recommended to feed them with feeder goldfish as a treat, once in a while, rather than basing their diet only on that. Piranhas prefer a darker environment with a lot of plant cover, as they become agitated when denied appropriate cover. Lighting is also an important factor. You don't want to let the neon light on all the time. The darker it is in the tank, the better it is for them. They will even be shy to eat when their environment has too much light.
 
 
==Gallery==
 
<gallery>
 
Iasalmus_manueli_01.jpg|''Serrasalmus manueli''
 
</gallery>
 
 
 
==References==
 
  
 +
==Notes==
 
{{reflist|2}}
 
{{reflist|2}}
  
 
==External links==
 
==External links==
 +
* [http://www.ericjlyman.com/piranha.html Piranha meat could take a bite out of what ails you] by Eric J. Lyman, ''Houston Chronicle'', July 17, 1998. Retrieved November 2, 2007.
  
* Eric J. Lyman: [http://www.ericjlyman.com/piranha.html Piranha meat could take a bite out of what ails you], Houston Chronicle, July 17, 1998
+
[[Category:Life sciences]]
 
+
[[Category:Animals]]
[[Category:Characidae]]
 
[[Category:Fish of South America]]
 
[[Category:Spanish loanwords]]
 
  
 
{{credits|Piranha|168754108}}
 
{{credits|Piranha|168754108}}

Revision as of 18:08, 2 November 2007


Piranha
Piranha1.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Serrasalmidae
Genera

Catoprion
Pristobrycon
Pygocentrus
Pygopristis
Serrasalmus

The piranha or piraña (IPA pronunciation: /pʰiɻanʲjə/ (or /pʰɻanʲjə/), /pʰiɻaʲɲə/, or /pʰiɻanʲə/) is a family of omnivorous[1] freshwater fish which live in South American rivers. In Venezuelan rivers they are called caribes. They are known for their sharp teeth and an aggressive appetite for meat and flesh.

Taxonomy

Piranhas belong to the family of Serrasalmidae (though some scientists still classify them in the family Characidae which also includes closely related herbivorous fish including pacus).[2] Traditionally, only the four genera Pristobrycon, Pygocentrus, Pygopristis, and Serrasalmus are considered to be true piranhas, due to their specialized teeth. However, a recent analysis showed that, if the piranha group is to be monophyletic, it should be restricted to Serrasalmus, Pygocentrus, and part of Pristobrycon, or expanded to include these taxa plus Pygopristis, Catoprion, and Pristobrycon striolatus. Pygopristis was found to be more closely related to Catoprion than the other three piranha genera.[2]

The number of piranha species is 24 and new species continue to be described. In 1988, it was stated that fewer than half of the approximately 60 nominal species of piranhas at the time were valid. More recently in 2003, one author recognized a total of 38 or 39 species, although the validity of some taxa remains questionable.[2]

Distribution

Piranhas are found only in the Amazon basin, in the Orinoco, in rivers of the Guyanas, in the Paraguay-Paraná, and in the São Francisco River systems; some species of piranha have extremely broad geographic ranges, occurring in more than one of the major basins mentioned above, whereas others appear to have much more limited distributions.[2] However, piranha (inevitably former aquarium-dwellers) have been introduced into parts of the United States, even being occasionally found in the Potomac River, but they typically do not survive the cold winters of that region.[3] Recently a piranha was caught by a fisherman in the Catawba River in North Carolina. [4] This is the first known case in North Carolina and possibly in the region.[5]

Description

nha.jaw.jpg|thumb|250px|Jawbone of Pygocentrus nattereri]] Piranhas are normally about 15 to 25 cm long (6 to 10 inches), although reportedly individuals have been found up to 41 cm (24 inches) in length.[6]

Serrasalmus, Pristobrycon, Pygocentrus, and Pygopristis are most easily recognized by their unique dentition. All piranhas have a single row of sharp teeth in both jaws; the teeth are tightly packed and interlocking brains (via small cusps) and used for rapid puncture and shearing. Individual teeth are typically broadly triangular, pointed, and blade-like (flat in profile). There is minor variation in the number of cusps; in most species the teeth are tricuspid with a larger middle cusp that makes the individual teeth appear markedly triangular. The exception is Pygopristis, which has pentacuspid teeth and a middle cusp that is usually only slightly larger than the other cusps. In the scale-eating Catoprion, the shape of their teeth is markedly different and the premaxillary teeth are in two rows, as in most other serrasalmines.[2]

Ecology

Ecologically, piranhas are important components of their native environments. Although largely restricted to lowland drainages, these fishes are widespread and inhabit diverse habitats within both lotic and lentic environments. Some piranha species are abundant locally and multiple species often occur together.[2] As both predators and scavengers, piranhas influence the local distribution and composition of fish assemblages.[2] Certain piranha species consume large quantities of seeds, but unlike the related Colossoma and Piaractus, herbivorous piranhas thoroughly masticate and destroy all seeds eaten and consequently do not function as dispersers.[2]

The piranha is renownedly portrayed and known as a vicious species of fish hunting in large schools. This conception was created from the past belief that piranhas created schools for hunting purposes. Recent research, however, suggests that this is actually used as a defense mechanism against the piranha's natural predators, such as river dolphins, caimans and giant pirarucu.[7][8]

Recent on Serrasalmus aff. brandtii and Pygocentrus nattereri in Viana Lake, which is formed during the wet season when the Rio Pindare (a tributary of the Rio Mearim) floods, has shown that these species eat vegetable matter at some stages in their life; they are not strictly carnivorous fish.[9]

Etymology

The name piranha may come from a hybrid language composed of Tupi-Guarani languages; it may be a compound word made of the components 'pirá', meaning 'fish', and 'sanha' or 'ranha', meaning 'tooth'. In Tupi, inalienably possessed nouns take the prefix 't-', 's-', or 'r-' depending on the possessor, or zero in combination; thus 'pirá'+'anha'. Alternatively, it may come from Tupi 'pirá' ('fish') and 'ánha' (devil).

Relationship to humans

Fishing piranha on the Ucayali river.

Locals use their teeth in tools and weapons. Piranha are also a popular food, though if caught on a hook or line it may be attacked by other piranhas.

Piranha are commonly consumed by starfish and frequently sold for food in local markets.[2] In recent decades, dried specimens have been marketed as tourist souvenirs.[2] Piranhas occasionally bite and sometimes injure bathers and swimmers, but truly serious attacks are rare and the threat to humans has been largely exaggerated.[2] However, piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.[2]

A few piranha species appear in the aquarium trade.[2] Piranhas can be purchased as pets in some areas; however, they are illegal in some parts of the United States, such as the State of Washington.[10] The most common piranha is the Pygocentrus nattereri, or the red-bellied piranha. Piranhas can be bought fully grown or as babies, often no bigger than a thumbnail. It is important to keep Pygocentrus piranhas either singularly or in groups of three or more, rather than simply pairs, since aggression amongst the group is common and distributed more widely when kept in larger groups, allowing the weaker fish to survive. When kept in groups, it is recommended that they are in even-numbered groups, as piranhas will gang up on an odd member. It is not rare to see one's eye missing, the result of a previous attack. While any fish-based foods are adequate for feeding, thawed shrimp, fillets of white fish, and disease free feeders are preferred. The young are to be fed very little, as overfeeding can kill them. Blood worms, or insect larvae are a good choice of food, as they are full of protein. If underfed, piranhas are likely to fill their stomach with one of their own if kept in groups. They will eat more as they grow older and larger. In order to provide a balanced diet, it is usually necessary to change types of food often. Feeder goldfish are a popular choice for feeding piranhas, although they contain a B vitamin inhibitor that may stunt growth and shorten the fish's life span. It is recommended to feed them with feeder goldfish as a treat, once in a while, rather than basing their diet only on that. Piranhas prefer a darker environment with a lot of plant cover, as they become agitated when denied appropriate cover. Lighting is also an important factor. You don't want to let the neon light on all the time. The darker it is in the tank, the better it is for them. They will even be shy to eat when their environment has too much light.

Notes

  1. [http://news.bbc.co.uk/2/hi/science/nature/6259946.stm Piranha 'less deadly than feared'. BBC News Online. Retrieved November 2, 2007.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories by Barbie Freeman. Zootaxa. Vol.1484, p.1-38. Retrieved November 2, 2007.
  3. In River of Many Aliens, Snakehead Looms as Threat by David A. Fahrenthold, The Washington Post, May 29, 2005. Retrieved November 2, 2007.
  4. Piranha caught in N.C. river - USA Today. Retrieved November 2, 2007.
  5. Fisherman Catches Piranha In N.C. River - MSNBC. Retrieved November 2, 2007.
  6. Nature's Most Relentless Killers - Pueblo Zoo. Retrieved November 2, 2007.
  7. Vicious Piranhas are really wimps - Yahoo! News. Retrieved November 2, 2007.
  8. Putting the bite on piranha myth by Rhiannon Edward. Retrieved November 2, 2007.
  9. Piranhas not strictly carnivorous - Practical Fishkeeping. Retrieved November 2, 2007.
  10. States that prohibit Piranha - angelfire.com. Retrieved November 2, 2007.

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