THE DANGEROUS PIRANHAS.........

Piranhas are small fish with a big reputation and big teeth!

Piranhas are freshwater fish, and live in the rivers and streams of South America.

The piranha’s fearsome reputation is partly due to fact, and partly due to fiction. 

Although piranhas are predatory, they are also just as likely to be preyed on by other animals.

Piranha Species

There are at least 20 species of piranha – and there could be as many as 60! Scientists are unsure of exactly how many species there are. Piranhas come in an array of different colors, including yellow, gray, blue, red, and black.

One of the most common species of piranhas is the red-bellied piranha, so named for its reddish belly. Another common type of piranha is the black piranha.

Appearance & Size

The piranha is a relatively small fish with a round body, large head, and bulldog-like face. Piranhas can grow to between 8 and 15 inches (20-37 cm) long. Piranhas swim in groups called shoals. There are usually around 20 piranhas in a shoal.

Although it was once believed that piranhas swim in shoals in order to attack, it is now thought that swimming in groups provides protection from predators.

Piranha Teeth

The piranha’s most notable characteristic is of course its set of razor sharp teeth. The teeth are triangular in shape and are used to puncture and tear the fish’s prey.

A piranha’s teeth are replaced continuously throughout its lifetime. The teeth grow in four sets; one for each corner of the fish’s mouth. Sets are replaced every 100 days. It’s not uncommon to find a piranha with half of its bottom teeth missing, waiting for the new set to emerge.

A young fish of only 6 inches can already possess teeth that are 1/6 of an inch long!

Relationship with Humans

Piranha teeth are often used to make tools and weapons by the indigenous population. Piranhas are also popular as food, although if an individual piranha is caught on a hook and line, it may be attacked by others.

Piranhas can be bought as pets in some areas, but they are illegal in many parts of the United States. It is illegal to import piranhas into the Philippines and violators could face six months to four years in jail.

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.

Piranhas Attacks

Attacks resulting in deaths have occurred in the Amazon basin. In the city of Palmas, Tocantins, 190 piranha attacks were reported in the first half of 2007. In 2011, a series of attacks in the Brazilian state of Piauí resulted in 100 people being injured. In the state of São Paulo, another attack in the Tietê River resulted in 15 injured people. In 2011, a drunken 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. Some Brazilian rivers have warning signs about lethal piranhas. On 25 December 2013, 70 bathers were attacked in Argentina. And in February 2015, a six-year-old girl died after being eaten by piranhas when her grandmother's boat capsized during a holiday in Brazil.

According to one study in Suriname, piranha attacks tend to peak in the dry season when food is relatively scarce and the water levels are lower, leading to heavier than usual concentrations of fish in the water. Fatal attacks are rare, and most attacks take the form of individual nips and bites to extremities such as the feet and hands. Splashing tends to make piranhas more likely to attack, and children are often attacked for this reason.

Pet  Piranhas?

Believe it or not, there are people who actually keep piranhas as "pets". Piranhas aren't good pets in the traditional sense because you can't hold or pet them, and they aren't affectionate. Piranha owners still must be extremely careful of the fish's sharp teeth and aggressive nature. Keeping them well fed is probably the key to keeping them mellow.

People who fancy piranhas as pets may be more attracted to the grisly reputation and aggressive manner of these world-class predators, perhaps keeping them for their "entertainment" value. That's O.K. - its human nature to be fascinated with morbid and gruesome creatures. But piranhas are also very beautiful fish. As long as anyone desires to take a creature out of the wild and bring into captivity they must take the responsibility of treating it with respect and good care.

                      Interesting Facts about Piranhas

1.  Piranhas have lived in South America for millions of years

   Today, piranhas inhabit the freshwaters of South America from the Orinoco River Basin in Venezuela up to the Paraná River in Argentina. Though estimates vary, around 30 species inhabit the lakes and rivers of South America today. Fossil evidence puts piranha ancestors in the continent’s rivers 25 million years ago, but modern piranha genera may have only been around for 1.8 million years.
   A 2007 study suggests that modern species diverged from a common ancestor around 9 million years ago. Also, the Atlantic Ocean rose around 5 million years ago, expanding into the flood plains of the Amazon and other South American rivers. The high salt environment would have been inhospitable to freshwater fish, like piranhas, but some likely escaped upriver to higher altitudes. Genetic analysis suggests that piranhas living above 100 meters in the Amazon have only been around for 3 million years.

2. Piranhas found outside South America are usually pets on the lam

   Piranhas attract a certain type of pet lover, and sometimes when the fish gets too large for its aquarium said pet lover decides it’s much better off in the local lake. In this manner, piranhas have shown up in waterways around the globe from Great Britain to China to Texas. It’s legal to own a piranha in some areas, but obviously never a good idea to release them into the wild, as the species could become invasive.

3. Piranha teeth are pretty intense but replaceable

   Piranhas are known for their razor-sharp teeth and relentless bite. (The word piranha literally translates to “tooth fish” in the Brazilian language Tupí.) Adults have a single row of interlocking teeth lining the jaw. True piranhas have tricuspid teeth, with a more pronounced middle cuspid or crown, about 4 millimeters tall.
   The shape of a piranha’s tooth is frequently compared to that of a blade and is clearly adapted to suit their meat-eating diet. The actual tooth enamel structure is similar to that of sharks.
   It’s not uncommon for piranhas to lose teeth throughout their lifetime. But, while sharks replace their teeth individually, piranhas replace teeth in quarters multiple times throughout their lifespan, which reaches up to eight years in captivity. A piranha with half of its lower jaw chompers missing isn’t out of the ordinary.

4. A strong bite runs in the family

   Though they are hardly as menacing as fiction suggests, piranhas do bite with quite a bit of force. In a 2012 study in Scientific Reports, researchers found that black (or redeye) piranhas (Serrasalmus rhombeus)—the largest of modern species—bite with a maximum force of 72 pounds (that’s three times their own body weight).
   Using a tooth fossil model, they found that piranhas' 10-million-year-old extinct ancestor, Megapiranha paranensis, had a jaw-tip bite force—the force that jaw muscles can exert through the very tip of its jaw—of as high as 1,068 pounds. For reference, the M. paranensis when alive weighed only 10 kilograms (about 22 pounds), so that’s roughly 50 times the animal’s body weight.
   Science notes that T. rex’s estimated bite force is three times higher than that of this ancient piranha—but the king of the reptiles also weight a lot more. M. paranensis also had two rows of teeth, while modern piranhas have just the one. It’s not clear exactly what this ancient fish ate, but whatever it was, it must have required some serious chomps.

5. Humans and capybaras are only part of the piranha diet if these prey already dead or dying

   The idea that a piranha could rip a human to shreds is probably more legend than fact, too. For the curious, Popular Science spoke to some experts who estimate that stripping the flesh from a 180-pound human in 5 minutes would require approximately 300 to 500 piranhas. Cases of heart attack and epilepsy that ended with the afflicted drowning in a South American river do show evidence of piranha nibbles, but in those instances, the victim was already deceased when piranhas got involved.
   While the myth of the man-eating piranha belongs to movie theaters, the Internet has a wealth of mysterious footage of piranha packs taking down capybaras. Some piranhas do occasionally eat small mammals, but as with humans, it’s usually when the unfortunate animal is already dead or gravely injured.

6. Some piranhas are cannibals

   A typical piranha diet consists of insects, fish, crustaceans, worms, carrion, seeds and other plant material. A red-bellied piranha (Pygocentrus nattereri), for example, eats about 2.46 grams per day—about one-eighth of its average body mass. Crustaceans, bugs, and scavenged scraps make up the largest chunk of their meals, but the balance of this diet can shift depending on the fish’s age and the food sources available.
   So occasionally when resources are low and competition for food is high, piranhas have been known to take a chunk out of a fellow piranha, living or dead. Even weirder, wimple piranhas (Catoprion mento) feed on fish scales, which contain a protein mucus layer that’s surprisingly nutritious.

7. Some are vegetarians

   Despite their flesh-eating reputation, some piranhas are omnivorous, eating more seeds than meat, and some even subsist on plants alone. For example, in the Amazonian rapids of the Trombetas basin in Pará, Brazil, scientists discovered that Tometes camunani lives solely off of riverweeds.
   
   Piranhas' closest relative, the pacu or tambaqui fish (Colossoma macropomum), also lives on a mostly meat-free diet. Pacus closely resemble some piranha species in size and coloration, and thus, are often sold at fish markets as, “vegetarian piranhas,” as well as other less flattering nicknames.

8. When hunting prey, piranhas go for the tail and eyes

   A 1972 study in red-bellied piranhas found that the fish most frequently attacked goldfish in a lab setting beginning with their prey’s tail and/or eyes. The researchers concluded that such an attack strategy would effectively immobilize piranhas’ opponents and prove useful for survival.

9. Piranhas bark

   From anecdotes and observational research, scientists have known for a while that red-bellied piranhas make bark-like noises when caught by fishermen. Upon further examination, a team of Belgian scientists found that they make three distinctive types of vocalization in different situations.
   In a visual staring contest with another fish, they start making quick calls that sound similar to barks, meant as a warning along the lines of, “Don’t mess with me, buddy.” In the act of actually circling or fighting another fish, piranhas emit low grunts or thud sounds, which researchers believe communicates more of a direct threat to the other fish.
   The fish makes these two sounds using its swim bladder, a gas-containing organ that keeps fish afloat. Piranhas contract and relax muscles around the swim bladder to make noises of different frequencies.
   The third vocalization? Should the opposing fish not back down, the piranha will gnash its teeth together and chase its rival. 
10.  Piranhas seem to be attracted to noise, splashing, and blood
     A 2007 study linked noise, splashing, and spilling food, fish, or blood into the river with three instances of piranha attacks on humans in Suriname. Piranhas might be naturally attuned to pick up on the sound of fruits and nuts falling from trees and hitting the water and, thus, mistake splashing children for the noise associated with food.
    As for blood, it likely does not render a piranha senseless as the movies would suggest, but piranhas can smell a drop of blood in 200 liters of water. So, if you are a bleeding, rambunctious child, a dip in the Amazon might not be the best idea.

11. They’re great grilled or in soup

    In some parts of the Amazon, eating piranha is considered taboo—a common cultural perception for predatory fish—while others are convinced it’s an aphrodisiac. Piranha soup is popular in the Pantanal region of Brazil, but many choose to serve the fish grilled on a banana leaf with tomatoes and limes for garnish.
12. Piranhas’ teeth are triangular shaped and as sharp as sharks’ teeth.
13. Only 3 species of Piranhas are considered dangerous to humans:
    a. Black shoulder Piranha
    b. Red-bellied Piranha (average sized at 13 inches and 3 pounds)
    c. Sao Francisco Piranha (largest at 24 inches and 13 pounds)
    
14. When Piranhas attack a large animal, they eat the flesh and muscle in seconds, and leave only the skeleton.