Wikimedia commons/AlexeyDr piranha

A well-known hymn says that the Lord God made ‘All things bright and beautiful, all creatures great and small …’ but could this possibly include the fearsome piranha? Dwelling in South American river systems,1 this fish is renowned for its razor-sharp teeth and its capacity to skeletonize within minutes any hapless animal that might fall into the water.

One species of piranha, Pygocentrus cariba,2 is notorious for being in schools of 30 or more, waiting for baby birds to fall out of nests overhanging the water. Evolutionists would assert that the ‘terrible piranhas’ bear witness to a world of ‘nature red in tooth and claw’, the result of long periods of evolution, with death and struggle acting to remove the weak and preserve the strong. How can the piranha’s gruesome behaviour be consistent with the Bible’s claim of a ‘very good’ world (Genesis 1:21,31), created by a God of love?

The answer is that today’s feared piranha and its behaviour was not a part of the ‘very good’ world that God originally made. It is living in a world that God made but has changed because of man’s Fall into sin. Through Adam’s sin, death, the ‘last enemy’ (1 Cor. 15:26)3 entered the world (Romans 5:12), and carnivory (meat-eating) by animals, fish and birds did not come about until after the Fall (Genesis 1:30).

For any particular carnivore, it is difficult to be certain whether its post-Fall features were (re)designed to cope in this fallen environment, or whether it just happened to adopt a different way of life—for example, in vampire bats, sharp teeth possibly once used for puncturing fruit could later be used to draw blood.4,5

Piranhas, though primarily carnivorous, are known to eat vegetable matter.

However, there is evidence that the ancestors of the piranha were once plant-eaters. Many species of South American pacu fish, identified by taxonomists as being ‘very closely related’ to piranhas, use their teeth and strong jaws to eat aquatic plants, and fruit that falls from overhanging trees. How closely related to piranhas are these herbivorous (plant-eating) species? Though some ichthyologists (scientists who study fish) in the past tried to distinguish between carnivorous piranhas and their vegetarian cousins on the basis of appearance, even experts found it hard to determine whether a specimen was a ‘piranha’ or ‘pacu’, and fish were frequently misidentified.6

The blurring between piranhas and pacus also extends to their diet. Piranhas, though primarily carnivorous, are known to eat vegetable matter as a component of their diet, and as at least one observer has noted, are probably more accurately described as ‘omnivorous opportunists’ rather than carnivores.1 I.e. they will eat ‘whatever comes along’. Their food varies according to season, food availability and age (young piranhas mainly eat microscopic plants and animals, and later, insects). Pacus, too, though mostly vegetarian, will eat meat rather than starve (though not known to nip off flesh from living animals)—thus explaining why anglers reel in pacu from time to time.7,8

On the basis of the similarities of all pacus and piranhas, creationist biologists would have presumed that they probably descended from the same created fish ‘kind’ (Genesis 1:20–22). Recent DNA analysis is consistent with this, in showing that there is no clear genetic difference between carnivorous and vegetarian species9—with some species even merging, to the surprise of experts.10 As one authority says, ‘There is evidence that some “pacus” are more closely related to piranhas than other “pacus”, i.e. that some pacus share a more recent common ancestor with piranhas than with the other pacus.’ 10

Piranha teeth are so sharp, they are used as razors by the Tucuna Indians.

So why did some of this kind (piranhas) become carnivorous while others (pacus) remained vegetarian? Possibly it came about like this: as fish populations increased in the South American river systems, there would have been increasing pressure on traditional food sources (aquatic vegetation and fallen fruit). Given the natural variation within a kind due to normal genetic processes, one might expect variability in tooth structure.

Are the vegetarian pacu’s teeth different from the carnivorous piranha’s teeth? One report says that the plant-eating pacus have a double row of teeth10—and pacus are clearly well-equipped for their vegetarian diet. By contrast, the carnivorous piranhas are reported to have only a single row of teeth (possibly loss of information by mutation?),11 but each upper and lower tooth interlocks in such a way that piranha teeth and jaws have been likened in strength and effectiveness (not size) to ‘a bear trap, but one with teeth so sharpened on the edges, and the spring so strong, that they would clip off the bear’s foot instead of merely holding it.’12 (Piranha teeth are so sharp, they are used as razors by the Tucuna Indians of South America.)1

Don Batten
The piranha’s vegetarian relatives, known as pacus.

Interestingly, the pacu species which is the most piranha-like in appearance, Pygocentrus denticulata13 (which lives on a diet of plant seeds), does not have the piranha’s razor sharp teeth but instead has rounded notched teeth ideal for shearing the husks off seeds.12

One can imagine a scenario where, with increasing competition for food, hungry fish, already endowed with piranha-like teeth, would have learned to put them to use in biting the flesh from carcasses of drowned animals or dead fish. Also, if a genetic copying mistake (mutation) caused some of the fish to lose one row of teeth, they would be less able to survive on plants, so would be forced to eat meat. This is not evolution, as it involves a downhill process, a loss of information. Once having learnt to scavenge carcasses, the classic piranha feeding behaviour could have followed soon after. One researcher studying piranha teeth commented, ‘The teeth are not made to lacerate, crush, tear, or even used to hold on to prey fish. They are meant to clip off small pieces of flesh or fins.’ 12 Piranhas apparently do not habitually eat whole fish but generally feed on small pieces of fins and flesh, ‘thus leaving a ready food supply …’ .2

This possible scenario for piranhas has a modern equivalent in the so-called ‘Vampire Finches’ of the Galápagos Islands. In the face of increasing competition between finches for traditional vegetarian foods, some have recently been filmed raiding the eggs and sucking the blood of nesting booby birds.14,15 The transition from herbivory to carnivory, seen in the context of God’s Word, makes sense, gruesome though it is. The created animals, birds and creatures of the sea were to multiply and fill all the earth, which after Adam’s sin became a corrupted world of death, pain and suffering.

Thankfully though, there is a Redeemer, in whom we place our hope ‘that the creation itself will be liberated from its bondage to decay and brought into the glorious freedom of the children of God’ (Romans 8:19–21).

Piranha clippings

  • When a piranha loses a single tooth, a whole set of new teeth quickly replaces the old. The new teeth are already formed in the gum area and do not drop down until the replacement is needed.1 (But the process seems limited, as very old piranhas can have extremely damaged and worn teeth.)2
  • The largest and most dangerous piranha is probably Pygocentrus piraya, which can grow to 60 cm (two feet). In most piranha species, adult fish are less than half this size.2,3,4
  • The most commonly seen piranha in the aquarium trade is the red (or ‘red-bellied’) piranha (Pygocentrus nattereri). However, owners are often disappointed to find their aquarium fish lack the vibrant colouring for which wild red piranhas are renowned. It appears that diet is a key factor in determining the external colouring.5 Colour intensity varies widely within wild populations, and within an individual fish’s lifetime.6,7
  • Wary of aquarium piranhas being accidentally or deliberately released into local waterways, some US states (e.g. Florida and Texas) prohibit their importation.8 Piranhas have already been reported in outdoor pools, lakes and rivers in Hawaii, mainland USA, and even Canada (though experts doubt they could survive a cold winter).9 Confirmed piranha captures can elicit drastic action by the authorities—in the past, whole lakes have been treated with rotenone (a poison) to kill all fish present, in an effort to prevent piranhas becoming established.9
  • Some piranhas are solitary, but most congregate in loosely organised groups. Their hunting techniques include ambush, stalking, and active chases. When stalking, piranhas invariably approach their prey stealthily from the rear. Some piranhas, instead of attempting to stay out of sight of their target, openly linger in full view without showing any apparent interest. They slowly edge closer, at the last minute dashing forward to clip off a piece of fin.10
  • Strategies to defend against piranhas often anticipate their rear-attack habit. As piranhas approach, cichlid fish may arrange themselves in a defensive ring with their tails to the centre. Bottom-dwelling species such as the wolf fish have been observed to hide their tails in vegetation or lay them flat on the bottom, when piranhas appear. Piranhas even seem wary of each other, especially when approached from the rear.10


  1. See Ref. 12 of main article. Return to text.
  2. Piranha teeth, http://www.geocities.com/Heartland/Hills/6993/html/body_teeth.htm, May 10, 2000. Return to text.
  3. See Ref. 7 of main article. Return to text.
  4. Encyclopædia Britannica, 15th edition, 9:466, 1992. Return to text.
  5. See Ref. 10 of main article. Return to text.
  6. Piranha Breeding, http://www.geocities.com/Heartland/Hills/6993/html/body_breeding.html, May 10, 2000. Return to text.
  7. Genus Pygocentrus, Red Piranhas, http:www.angelfire.com/or2/piranha038/pygo.html, April 27, 2000. Return to text.
  8. Are they legal? Or not?, http://www. piranha.org/legal.html, May 9, 2000. Return to text.
  9. See Ref. 6 of main article. Return to text.
  10. See Ref. 1 of main article. Return to text.

The President, piranhas, and the press

Are piranhas dangerous to humans? Experts generally agree that the ferocity of piranhas has been greatly exaggerated.1 There are no records of humans ever having been killed by piranhas,2 but piranhas are known to have skeletonized the victims of drowning.3 The origin of the ‘legend’ of piranhas being ever-ready to attack any human foolhardy enough to enter the water has been traced back to 1913–14, when then ex-US President Theodore Roosevelt visited the Amazon river system.2,4,5 The Brazilians arranged a spectacular tour of their country through the rainforest, putting together an itinerary that included a river that Roosevelt could ‘discover’ (later called Rio Theodore Roosevelt, which is actually the arm of another Amazon tributary, Rio Aripuana).

The ex-President was accompanied by a hundred journalists, many of whom had never been in the jungle before. The Brazilians had specially prepared for the ‘discovery’ of the Rio Theodore Roosevelt by isolating this portion (about 90 metres, or 100 yards) of the river with nets. For weeks, Amazonian fishermen had caught piranhas with hook and line, throwing them into this netted off area. When Roosevelt and his entourage ‘happened’ upon the river, the Brazilians told them not to venture into the water because they would be immediately eaten by piranhas. Demonstrating their point, the Brazilians took a live cow, slit her udder, and drove her, bleeding, into a seething mass of starving, trapped piranhas. The cow was quickly stripped to the bone by the piranhas, which leaped out of the water in a feeding frenzy, to the amazement of the President and the accompanying journalists witnessing the scene just a few metres (10 feet) from shore. The newspapers around the world described this scene, embellishing the account by saying anyone entering the water would be immediately attacked and devoured by these fearsome small fish. Roosevelt wrote of the episode in a popular 1914 book—his estimation that ‘Piranhas are the most ferocious fish in the world’ magnified the mystique and fear still further. Even Hollywood added to the myth by making movies showing humans being attacked by flying piranhas with long, gruesome-looking teeth!2

In certain circumstances, piranhas do pose a real threat to man or livestock—usually, when conditioned to a ready food source, e.g., fish-cleaning offal habitually thrown into the water at the same place.6 Also, when waterholes, dug for cattle, become connected to the main river system during floods.2 As the waters recede, piranhas can become trapped and increasingly deadly as they starve, as Roosevelt saw.

Mostly though, piranhas are not considered to be as dangerous as their reputation would imply. Indigenous South American people often swim in waters filled with piranhas, without being bothered.6 (In fact, a local freshwater stingray causes many injuries with its venomous barbed tail, and is regarded by local people as being far more dangerous than the piranha.)7,8 Careless handling by fishermen removing fish-hooks or disentangling piranhas from landed nets is the key factor in most injuries.3


  1. See Ref. 6 of main article. Return to text.
  2. See Ref. 2 of main article. Return to text.
  3. Genus Pygocentrus, Red Piranhas, http:www.angelfire.com/or2/piranha038/pygo.html, April 27, 2000. Return to text.
  4. Merit Students Encyclopedia, 16:168, 1968. Return to text.
  5. Encyclopædia Britannica, 15th edition, 27:710, 1992. Return to text.
  6. Relax, It’s Only a Piranha, http://www.smithsonianmag.si.edu/smithsonian/issues99/jul99/piranha.html, May 25, 2000. Return to text.
  7. Piranha Facts, http://members.aol.com/_ht_a/piranhahut/map.html, May 10, 2000. Return to text.
  8. News from the zoos, http://www.umich.edu/~esupdate/library/98.09-10/zoos.html, May 10, 2000. Return to text.

Published: 31 October 2012

References and notes

  1. Piranha’s Nature, http://www.piranha.org/nature.html, May 9, 2000. Return to text.
  2. Known locally as the caribe capa-burro, or ‘donkey castrator’, Legendary Myth of Piranha Revealed, http://www.angelfire.com/biz/piranha038/myth.html, May 9, 2000. Return to text.
  3. Creatures without what the Bible calls nephesh or ‘soul-life’ do not have ‘life’ in the biblical sense, and thus may have died before the Fall in a biological sense. Nephesh-life seems to be tied up with a certain level of consciousness—plants are certainly not accorded nephesh in Scripture. It is probable that micro-organisms, and perhaps even insects, do not have nephesh-life. Return to text.
  4. There may also have been latent genetic information because God foreknew the Fall. See The Creation Answers Book. Return to text.
  5. See also Woodmorappe, J., The Dracula connection to a young earth, Creation 21(1):32, 1998. Return to text.
  6. Nonindigenous fishes—Pygocentrus nattereri, http://nas.er.usgs.gov/fishes/accounts/characid/py_natte.html, May 2, 2000. Return to text.
  7. Piranha species, http://members.aol.com/_ht_a/piranhahut/species.html, May 10, 2000. Return to text.
  8. Fish native to the Amazon caught in Alabama waters, http://www.alabamalive.com/columnists/birmingham/mbolton/07081999-e221411b.html, May 15, 2000. Return to text.
  9. Piranhas and new DNA Evidence, http://www.angelfire.com/biz/piranha038/dna.html, April 28, 2000. Return to text.
  10. Sub-family Serrasalminae, http://www. angelfire.com/biz/piranha038/pg2.html, April 27, 2000. Return to text.
  11. Possibly because of the confusion over species identification, not all ‘experts’ agree that the carnivorous piranhas have only a single row of teeth while the vegetarians have a double row. One website lists two carnivorous species as being endowed with two parallel curved rows of teeth in the upper jaw. Piranha Biology, http:/www.piranha.org/biology.html, May 9, 2000. Return to text.
  12. Teeth of the Piranhas, http://www.angelfire.com/biz/piranha038/teeth.html, April 28, 2000. Return to text.
  13. The identification and naming of various piranha species is in a state of flux. Most piranhas are commonly assigned the genus name Serrasalmus, whereas other authorities use the subgenus name Pygocentrus for several species. Ref. 10. Return to text.
  14. Weiner, J., The Beak of the Finch, Jonathan Cape Random House, London, UK, p. 17, 1994. Return to text.
  15. Islands of the Vampire Birds, ABC TV (Australia), broadcast October 13, 1999. During extended drought periods, the seabirds’ blood is probably the most important food source for the vampire finch. The finches begin by landing on the booby’s tail. They peck at the base of the wing feathers to break the skin and draw blood, then sip it every few seconds. Other finches queue up behind the booby as if at a blood bank—as soon as one finch leaves, another takes up its blood-sucking perch. http://www.abc.net.au/nature/vampire/finches.htm, May 11, 2000. See Vampire finches of the Galápagos. Return to text.

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