Are piranhas dangerous for humans? June 24th, 2018
From films and fiction books, we know that if you put your hand in the water where piranhas live, they will gnaw it off in a minute. Well, okay, maybe this is not accurate, but if there is some kind of wound on the body and blood gets into the water, then the piranhas can smell it a kilometer away and will definitely attack a person with the whole flock and certainly only a skeleton will be left of him.
Is this really true?
First you need to understand whether the piranha is really an extremely aggressive creature that attacks everything that moves in the water. This may sound unexpected, but piranha is a very cautious fish and does not pose any danger to humans. Exists a large number of evidence of a person swimming in piranha-infested water without any harm to his health.
This was fully demonstrated by Herbert Axeldorf, a famous biologist specializing in the study of tropical fish. To prove the safety of piranhas for humans, Herbert filled a small pool with piranhas and dived into it, leaving only his swimming trunks on. After swimming for some time among predatory fish and without receiving any harm to his health, Herbert took the fresh blood-soaked meat in his hand and continued to swim with it. But several dozen piranhas in the pool still did not approach the person, although quite recently they happily ate the same meat when there was no one in the pool.
Piranhas considered scary predators with an insatiable thirst for fresh flesh, are actually quite timid fish and SCARBERS, not daring to approach large creatures.
It is known that piranhas prefer to stay in large schools, and if one piranha is seen in the water, there are always others nearby. But piranhas do this not because it is easier for a school of predatory fish to overwhelm and kill a person who enters the water, but because piranhas themselves are a link in the food chain for other more large species fish Being in a flock of dozens of individuals, the chance that you will be eaten is quite low.
Moreover, experiments with piranhas have shown that when alone, these fish do not feel as calm as if they were surrounded by other fish.
But, despite their peaceful behavior towards humans, piranhas are real killing machines for other species of fish that rank below them in the food chain. Their powerful jaws are designed to bite and tear, and their dense, muscular bodies are capable of incredibly fast movements and jerks underwater. The piranha's jaw muscle contraction force relative to body size is believed to be the highest of any other vertebrate in the world. For example, the common piranha can easily bite off the finger of an adult.
But in history there has not been a single reliable case of a piranha attack on a person with fatal. But this does not mean at all that these fish never bite a person or an animal that enters the water. And this behavior is almost always caused not by the aggressive behavior of the fish, but by self-defense or abnormal weather conditions, because of which the behavior of the piranhas begins to differ sharply from usual. Abnormal weather conditions mean a period of drought, when the rivers in which piranhas live dry up, and many fish remain in depressions filled with water, but cut off from the main channel, deprived of food. Starving predators gradually begin to eat themselves and may well rush at any creature that comes close to the water. Sometimes the tendency of piranhas to aggressive behavior recorded during the spawning period, when they rush at a person or animal in self-defense, but such cases are extremely rare. And of course there is no talk of a collective attack by piranhas on humans.
Surprisingly, piranhas, being, according to many, one of the most the most dangerous predators, at the same time unusually timid! It is advisable to keep the aquarium in which piranhas live away from sources of noise and shadows, otherwise your pets will constantly be on the verge of fainting! It is a well-known fact among aquarists that a click on the glass or a sudden movement near the aquarium is enough for piranhas to faint. They also often faint during transportation from the place of purchase to their future home.
But all of the above does not mean that piranhas will refuse to eat human meat. Unfortunately, sometimes tragic incidents occur on the water - people or animals drown. An already lifeless body floating in the water attracts many fish, including piranhas, which leave specific bites on it. People who see this think that the cause of death was an attack by piranhas - this is how most myths about attacks by flocks of piranhas on people or animals are born.
And here's Paku for you - common name several species of omnivorous South American freshwater piranhas. The pacu and the common piranha (Pygocentrus) have the same number of teeth, although differences in their alignment are noted; The piranha has pointed, razor-shaped teeth with a pronounced mesial bite (the lower jaw protrudes forward), while the pacu has square, straight teeth with a slight mesial or even distal bite (the upper front teeth are pushed forward in relation to the lower ones). As adults, wild pacu weigh more than 30 kg and are much larger than piranhas.
here's more about them -
Confident that underwater fauna greedy for human flesh is more often found in movies than in reality, a modern resident middle zone I long ago rejected the possibility of becoming a victim of a predator. But if you are brought to South America, you need to be prepared for anything.
A sharp-toothed piranha successfully fights an anaconda and a chupacabra for honorary title the most terrifying creature in South America. There is some truth in the most fantasy stories, but in real life the fish glorified by Hollywood (even the young James Cameron, the author of the unforgettable “Terminator” and “Avatar”, made films about them) and occupying an important place in the terrible tales of the local population turn out to be completely different. Let's try to dispel the most common myths about this river predator and give some useful tips for those who bought tickets to Brazil or Mexico.
Everyone knows that piranhas live in troubled waters Amazons. And this is true, the diversity of species inhabiting this great river, extremely large. But it is worth knowing that the habitat of piranhas is very extensive; they can be found in almost any river of the South American continent. At the same time, it will be news to many horror movie fans that some types of piranhas are herbivores. And among predatory species Only three or four of these fish can pose a danger to humans.
The main food of piranhas is carrion, and not tanned blondes in bikinis. If wolves are called orderlies of the forest, then with the same success toothy fish can be called orderlies of rivers. Any dead animal is gnawed clean by them and does not contaminate the water with corpse decomposition. Even the most aggressive piranhas will choose dead body, ignoring live prey. And when an “appetizing” person begins to splash around near a school of hungry piranhas, the toothy hunters will prefer to look for smaller prey. Mostly representatives of the fish kingdom suffer from their teeth, although waterfowl snakes and even birds that land on the water also suffer.
Not all types of piranhas are small, palm-sized. Some grow to almost half a meter in size. Common feature For the entire family of piranhas there is a special structure of the jaws and the arrangement of the teeth. When biting, the extremely sharp triangular teeth of these fish fit together so tightly that the predator does not bite off the victim’s flesh, but rather cuts it off. The closest analogy is well-sharpened scissors or a zipper on clothing. Also, all piranhas are characterized by instinctively coordinated “work” in a school. When attacking, each fish bites and immediately gives way to its “colleague”. As a result, even large animals like tapirs are gnawed to the bone in record time.
Quite a surprise for fans scary stories will be the fact that in the entire history of modern South America, not a single case of human death from the teeth of piranhas has been officially recorded. Most creepy stories about bloody atrocities in river waters you can hear from local fishermen. And fishermen, you know, tend to slightly exaggerate and dramatize a little in any country and on any continent. For example, upon closer examination of the high-profile tragedy of 1976 in Brazil, it was revealed important details: then in deep river A bus full of passengers fell, killing almost forty people. Their corpses were eaten by piranhas, and the sensational press accused the predators of massacring people. But a survey of the few survivors showed that when they got off the bus, they did not see any piranhas and, moreover, were not attacked by them. And the bus was raised to the surface only a few hours after the accident; with a high degree of probability, the discovered traces of piranha bites were already left on the corpses.
But don't neglect a set of those razor-sharp teeth. Piranha attacks on people without fatal outcome happen with frightening regularity. In most cases, victims get by with a couple of painful bites, but there are many cases of piranha attacks that have resulted in serious injuries. In 2013, more than 60 people, including seven children, were injured in a massive piranha attack on a river beach in Argentina. Many were hospitalized; some victims had their phalanges of fingers or toes bitten off. Biologists explained this attack by unprecedented heat. To protect yourself from piranhas, you really should monitor the weather and the changing seasons. During the Amazon and other spills large rivers piranha hunting grounds are expanding significantly. The fish receive food in abundance, largely due to the corpses of land animals caught in the sudden rise in water levels in those parts. And during periods of heat and drought, when large flocks The piranhas find themselves squeezed into the narrow banks of shredding rivers; none of the aborigines will happily splash around in the muddy water.
In accordance with the canon of the adventure genre, piranhas react vividly to blood. Life in the muddy streams of the Amazon has taught this species to rely primarily on its sense of smell, so they can smell blood in the water in a ratio of one to one and a half million. And the fact that piranhas become more aggressive at the same time is not surprising: absolutely all animals react to blood, even a harmless cow is capable of inappropriate actions at the sight of blood.
Very often, those who hunt piranhas themselves become victims of bites. We're talking about fishermen. No, piranhas do not systematically take revenge on people with fishing rods. But when removing a caught piranha from a hook, you can easily lose a finger. Even fish caught and thrown ashore are capable, on occasion, of firmly clinging their teeth to the offender. But their meat is considered a delicacy, and daredevils, casting aside doubts, rush with gear to the banks of South American rivers. And the naive piranha bites almost on a bare hook, you just have to tug it in the water, imitating movement.
The piranha fish inspires horror not only in its native South America, but also to residents of all other continents. In terms of the number of myths, only a huge shark can be compared with a small river inhabitant.
She is the only one who can compete with her in bloodthirstiness and sharp teeth. And although the piranha is significantly smaller in size than the shark, this does not prevent it from freely ruling the South American rivers and lakes from Venezuela in the north to Argentina in the south.
Biological diversity
In total, ichthyologists count 9 genera, consisting of 58 species of piranhas. Only 25 species are predators, and the rest are herbivores. However, according to scientists, several thousand unknown species of characin fish (including piranhas) may live in the waters of hitherto unexplored areas of South America.
The largest types of piranhas
The largest species of piranha reach a length of half a meter and weigh 2.5 kg, and the smallest are only 25 cm and weigh 0.5 kg, but, regardless of size and color, all piranhas have teeth of amazing sharpness. Serrasalminae ( Latin name"Zubastikov") belong to the order Cyprinidae, family Characinidae, subfamily Sawtooth.
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Piranha teeth
Contrary to classification, piranha teeth do not resemble a saw, but rather a razor or sharply sharpened scissors. They have a triangular shape (the upper triangle fits into the groove between the lower ones) and reach 4-5 mm in length. These teeth aren't just a razor-sharp metaphor: Indians actually used them as razors in ancient times.
But alone sharp teeth Piranha is not limited. She has surprisingly powerful jaws. First, the jaws close and the teeth cut off what is in the mouth from everything else. Then the closed jaws move horizontally (that is, the piranha seems to be chewing), and its teeth, like electric razor knives, bite more hard materials, so that neither sinews and bones, nor even thick sticks can resist the jaw!
Gastronomic delicacy
Residents of South America catch and enjoy eating piranhas, whose meat tastes like trout, although catching it is not so easy. To catch piranhas, they use huge hooks, which are used to catch huge fish weighing tens and hundreds of kilograms (and piranhas weigh only 0.5–2.5 kg) and thick fishing line. However, even after getting off the hook, the piranha will approach the bait again and again until it gets caught for dinner.
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Origin of the name: piranha
Piranha fish got its name from the word “pirusinha”. This is what the Topu Indians who lived in Brazil called it. “Piru” in their language means “fish”, and “sinya” means “teeth”, that is, “pirusinha” means “toothed fish”. The Portuguese who arrived in Brazil changed the name to the more familiar “piranha” or “piraya”, which translated means “pirate”.
In Germany and Russia, this fish received not at all menacing names: the Germans call this fish, round like a coin and covered with small shiny scales, “silver thaler”, and in our country it received the nickname “coin” or, depending on the size, “ruble” ", "kopeck piece" and so on. The Spaniards call this fish “cariba”, that is, “cannibal”, because, completely hungry, the piranha attacks its smaller comrades in the flock.
Unsurpassed survivability of piranhas
In general, it is common for piranhas to eat a piece of a friend. The barely grown fish (1.5–2 centimeters in length) are already tearing pieces of meat out of each other. At the same time, despite the sharpest teeth, it does not come to murder. A hungry piranha needs very little meat to satisfy its hunger, so taking a bite from its neighbor usually calms it down. And the victim soon recovers, because piranhas have an amazing ability to regenerate, and bitten off pieces of meat grow back in them.
Piranhas are river hyenas, very dangerous for all mammals and humans, predatory fish. Hearing the word “piranha”, a person will immediately imagine film footage of a huge toothy fish chasing a person. There is some truth in this idea.
Share - because not all piranhas are predators, and they are not such huge fish. Its average size is 35–50 cm, but there are specimens up to 80 cm.
What types of piranhas are there?
There are piranhas that only eat aquatic plants. These include the species Colossoma bidens. The remaining representatives are predators. Lives in fresh water bodies South Africa about fifty species, the exact number is unknown.
They choose different habitats - some species live in quiet, slow waters, while others prefer swift and rapid currents.
Some of them are bred at home. A flock of quiet ones, small fish will decorate any aquarium. They are fed squid, capelin and meat.
In nature, there are several species of predators, the most dangerous is the species Pygocentrus nattereri .
The most dangerous piranha— Pygocentrus nattereri Features of appearance and behavior
Piranhas vary in size, head shape, and shades of skin color. Basically, the coloring of adult piranhas is silvery-olive on the back and sides. The abdomen has a purple or red tint. The very edge of the tail is bordered by a bright black line.
But its most distinctive feature is its teeth. When its mouth is open, its triangular teeth measuring 5 mm in size look terrifying. Moreover, they are designed in such a way that when a piranha clenches its jaws, upper teeth fit tightly between the lower ones, forming a semblance of a solid sharp razor.
The jaws are driven by very strong muscles, thanks to which sometimes a bite with only the front teeth is sufficient.
With them, she not only tears out pieces from the victim, but can also bite through bones and veins. There are known cases when piranhas easily bit off a human finger or a thick stick.
Piranhas are the only “talking” fish!
Most fish in nature do not make any sounds. Piranhas are an exception to this rule. Surprisingly, they can croak when they get close to each other. When fighting, the sound they make is similar to drum roll. When they are taken out of the water, you can hear sounds reminiscent of angry barking.
All species of these fish have excellent hearing and sense of smell. They can smell and hear prey at a distance of 7 km. Moreover, literally a drop of blood from the slightest wound on its body is enough for the piranha to instantly rush to feast.
Schools of fish immediately rush to the place where the prey is located. They are not afraid of either large animals or fish, which can be 10 times larger in size. If one of the piranhas itself receives a wound, then it is likely that its relatives will attack it too. Even a crocodile can give up in front of a pack of these ferocious predators and tries to quickly swim away, turning over with its belly up for safety.
Many stories are associated with the gluttony of piranhas. There is a known case when a flock gnawed to the bones a pig that had fallen into the water. Fishermen are often their victims. Piranha meat is edible and resembles perch. It is especially tasty when fried. They catch it with a fishing rod, and if the fisherman is careless when removing the fish from the hook, then it can snatch off his finger. Not in vain from the tongue different nations The name “piranha” is translated as “toothed devil”, “evil fish”, “pirate”.
But more often than not, all these stories are exaggerated. Piranhas become aggressive only when water bodies dry up. The fish have nothing to eat and have to eat everything they can find. During the rainy season, when the rivers are full of water, people swim and ride boats calmly next to swimming piranhas.
Piranha is a type of predatory fish. It is rightfully considered one of the most dangerous in the world. And you can find it in the Amazon, Paraguay, Parana and Essequibo river basins.
Common piranha grows on average up to 20 centimeters. The mass of an individual is up to one kilogram, no more, but there are exceptions. Fear is caused by the large features of the head, as well as protruding teeth, which, in fact, pose a threat. The teeth are sharp, like a razor. Each is no more than one centimeter long, but usually up to 5 millimeters. With them, the fish instantly pierces the skin of its victim, and for the piranha it does not matter whether it is a person in front of it or an animal. With its teeth, a predator can easily bite off the finger of an adult. The fish differ slightly in color from each other. As a rule, the sides of the piranha are silver or dark, and the color itself is olive green or bluish-black.
Small fish live in schools and most spend their time searching for food. Piranhas are voracious, so they can often be found in bodies of water where there is actually a lot of prey. Moreover, sometimes the predator can be found not only in rivers, but also in the seas, but not during spawning. By the way, piranha was sometimes found in unusual climatic conditions- cold rivers.
Piranha in an aquarium
As a rule, the fish waits for the victim in a shelter. And they instantly attack their prey. The latter does not even have time to realize how and what happened. And when a predator hunts a school of fish and the victims scatter, piranhas catch them one by one, and then swallow them whole or bite off pieces of meat. Scientists have found that toothy fish have a very sensitive sense of smell, so they notice any odor that comes from a potential meal. And best of all, piranhas sense blood. They say that a flock of adults is capable of destroying everything in its path, not even sparing underwater plants. And the only ones who are not afraid of voracious fish are catfish of the genus Hoplosternum. And why, experts still cannot understand.
There are many stories in which we're talking about about the attack of these aggressive predators on humans. But in fact, most of the stories are fictitious. However, cases where fish actually attacked a person are not isolated.
Giant Nibbler
The largest piranha man has ever seen has grown to 80 centimeters in length. She weighs about 2 kilograms. You can even find one like this in Russian reservoirs. For example, one specimen fell into the usual nets of fishermen in Kazakhstan (near the village of Mutkenova, Pavlodar region). But in fact, the fish is found in South America and, scientists say, the life of our weather conditions unacceptable to her. Ichthyologists claim that the piranha could have been released from a private aquarium (and this is not an isolated case), and the fish adapted to unusually low water temperatures. In this case, the survivability of the piranha is amazing.
Another monster was caught by British traveler and fisherman Jeremy Wade. He caught a miracle of nature in Africa during his expedition to the Congo. His catch grew to one and a half meters in length, and in the giant mouth there were exactly 32 huge sharp teeth. They were similar in size to the teeth of a white shark.
However, experts say that this is a Goliath tiger fish, which is one of the most terrible freshwater fish in the world. A deadly and larger version of the piranha. With her set of teeth, she can even attack crocodiles.
There are five known species tiger fish, but the largest lives exclusively in the Congo River basin. The predator grows up to 180 centimeters in length, and gains weight up to 50 kilograms. Goliath eats different fish smaller in size, sometimes for lunch it eats small animals that have fallen into the water, and can attack humans.
Catching such a fish is quite difficult. With her sharp teeth she is able to bite through fishing line of any thickness. Therefore, for hunting Goliath, special steel leashes of increased strength are made.
However, contrary to popular belief, the 50-kilogram Goliaths that are found in some African rivers are not actually piranhas.
Bite force
How strong is a piranha and how scary are its teeth. This question was answered international group scientists from Egypt, Brazil and the USA. Experts conducted a study aimed at measuring the bite force of the common diamond-shaped piranha. Why was this particular individual chosen? Because it is the largest piranha in the world, up to forty centimeters in length and weighing more than a kilogram.
For the sake of the experiment, scientists caught several large species of fish from the Amazon River and began poisoning them with dynamometers. During this study, by the way, specialists took great risks with their own fingers, since predators could freely bite off a person’s limbs instead of the device.
All about piranhas
One way or another, piranhas willingly took part in a special experiment. And they only bit the proposed dynamometer. And the result of the study was impressive. Most powerful bite amounted to three hundred twenty newtons. And this figure turned out to be the highest among animals. That is, the piranha bites the most powerfully among all the animals that now live or once lived on Earth.
According to scientists, even the famous tyrannosaurus, which lived many millions of years ago, did not have such a strong bite. And the only one who could compare in bite force with the piranha was its direct ancestor, who lived during the times Jurassic. It was an order of magnitude larger than the current fish. Its length was one meter and thirty centimeters. The fish weighed more than seventy kilograms.
And the bite force of this ancestor was approximately four and a half thousand newtons. If we return to the tyrannosaurus, its bite force was three times stronger, but this is taking into account the enormous difference in weight (the tyrannosaurus reached ten tons). Therefore, the palm in terms of bite force belongs only to the piranha.
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