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Top 6 Piranha Facts

  |   Wildlife & Flora

Piranha are a freshwater fish commonly found in the Amazon basin. There are around 30 species in known existence, with average sizes ranging from 5 to 10 inches in length - though in rare cases they can extend up to 24 inches. They are a diverse animal, with different types displaying a range of colours and patterning, from yellow to black, steely grey to dark red, often with colourful underbellies. 

Piranha are known for their sharp vicious-looking teeth and insatiable appetite, which partly accounts for their ferocious and rather fearsome reputation. But the piranha is in many ways a misunderstood creature. As you’re bound to encounter some on an Amazon river cruise, here are the Top 6 Piranha Facts to help uncover the mystery and misconceptions behind this intriguing fish. 


Red-bellied Piranha (Pygocentrus nattereri).

Red-bellied Piranha (Pygocentrus nattereri).

1. Piranhas are Native to South America

The piranha is native to the northern half of South America, where it has lived for millions of years, residing in warm freshwater rivers, lakes and streams. It is particularly prevalent in the Amazon basin, Orinoco River in Venezuela and the Paraná River in Argentina. However, piranhas have been introduced to various areas worldwide, including North and Central America, Hawaii and Bangladesh. 

They are also kept as pets in some parts of the world. However, owners sometimes have a change of heart (typically when the fish grow too big) and release them into the wild, explaining why piranha have sometimes been found in places outside their native home such as in the UK and China.



A spectacled caiman (Caiman crocodilus) eating fresh piranha in Venezuela. (Ph. W. Perry Conway/CORBIS)

A spectacled caiman (Caiman crocodilus) eating fresh piranha in Venezuela. (Ph. W. Perry Conway/CORBIS)

2. Piranhas Live in Protective Packs

Shoals of piranhas can be found in numbers of up to 1000. Contrary to popular thought this tendency to stick together is not a hunting technique, but a form of self-defence. Piranhas - particularly when they are young - are actually the meal of choice for several animals, including caimans, river dolphins, turtles, otters, birds and other larger fish. Schooling together enables the fish nearer the centre of the shoal to remain protected and to respond to predator attacks with greater calm and skill. 



Red Bellied Piranha

3. Piranhas are Omnivores

The popular image of piranhas is one of a vicious, flesh-eating (even human eating) predator that devours its prey in a matter of seconds, creating a big bloody frenzy that leaves only the skeleton behind.

The reality is a little more nuanced. Piranhas are omnivores, their diet typically consisting of insects, fish, snails, worms, seeds and various plants. They will only tend to eat larger creatures, such as mammals and birds if they are dead or dying and have fallen into the water. 

Feeding frenzies are only triggered when there is blood in the water or during food shortages when the fish become more aggressive. Like sharks, piranhas are equipped with specialised sensory organs that make them especially sensitive to the presence of blood in the water. When food is scarce, piranhas have been known to resort to cannibalism, preying on chunks of their own weaker or sick members.

On the other hand, some piranhas are actually vegetarian, as well as being pretty docile creatures. The Tometes camunani species, which resides in the Trombetas basin in Pará Brazil, was found to subsist on a diet consisting solely of aquatic weeds.



The jaw bone of a red-bellied piranha (Pygocentrus nattereri) specimen. (Ph. Wikimedia Commons/Sarefo)

The jaw bone of a red-bellied piranha (Pygocentrus nattereri) specimen. (Ph. Wikimedia Commons/Sarefo)

4. Piranhas Shed Their Fearsome Teeth

The word piranha literally translates as “tooth fish” in the indigenous Brazilian language of Tupi. Here are a few thought-provoking facts about the piranha’s famed teeth: Each fish possesses an unusually large lower jaw and just one row of many razor-like teeth, which are as sharp as those of a shark. Piranhas have a pretty impressive and relentless bite force, and their teeth are strong enough to able to pierce a fishing hook made of silver. Their teeth are entirely replaceable, and they tend to shed them on a regular basis, regrowing them in chunks at a time.



Piranha Bones

5. You Won't Get Eaten By A Piranha

Given their less than friendly reputation, you may be wondering whether a piranha poses any sort of threat to humans. Thankfully, images perpetuated by Hollywood movies (such as the 2010 3D remake of cult film Piranha) featuring piranhas viciously feasting on groups of unsuspecting swimmers are only unhelpful myths. 

Piranhas will only consume flesh in the water that is already dead or dying, and they certainly don’t have the capacity to shred a living human or other animal into pieces in mere minutes. These stories are the product of exaggerations that have been perpetuated over the generations. You’ll be glad to hear that there are certainly no documented incidences of fatal piranha attacks on humans! 

In theory, though, it is possible for people to be bitten, experiencing a light nibble on the fingers or toes. Fishermen, especially, have to exercise care when taking piranhas out of nets. Whilst most of these relatively small fish are quite timid and harmless, there are a couple of more aggressive species. The black and red-bellied piranhas are considered the most hostile and you may want to exercise a little caution around these. In practice, though, unless the water level is very low, you disturb their eggs, or food is in very short supply, you’re very unlikely to ever be bitten. 



Piranha Fishing Amazon River

6. Piranhas are Often Used by Humans

In reality, piranhas have far more to fear from us, than the other way around. These fish have been used for millennia as a source of food by locals and for selling in the commercial pet trade.  Their razor-like teeth are also highly prized by native South Americans for use in tools and weapons.

You may well have the chance to go fishing for various species on your Amazon river cruise, and to even have a taste. Piranha is a delicacy in certain parts of the Amazon, whether it’s being made into a soup, or wrapped and grilled in a banana leaf served with tomatoes and a garnish of lime. 


There you have it! Piranhas are not as scary as they are perceived to be. Contact Us if you have any questions about our Top 6 Piranha Facts, or if you're ready to see these infamous creatures in real life on an Amazon River Cruise

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