Piranhas are monsters from horror films and scary stories, small but bloodthirsty inhabitants of the waters of the Amazon and other rivers in South America (Colombia, Venezuela, Paraguay, Brazil, Argentina). And what do we know about them? Perhaps nothing. After all, all knowledge is limited to just one species - an ordinary piranha, which has earned itself a bad reputation.
What does a piranha fish look like?
The Piranha family has a little over 60 species of fish. And, oddly enough, most of them are herbivores, they practically do not eat animal food. The size of piranhas depends on the species, carnivores mostly reach 30 cm, and their vegetarian relatives can gain significant mass and grow more than one meter in length. The coloration also depends on the species, but is mostly silver-gray, becoming darker with age. The shape of the body is diamond-shaped and high, laterally compressed. The main food for predators is a variety of freshwater fish, piranhas can also eat animals or even birds that they meet on the way. For herbivoresspecies The Amazon and its tributaries abound in various vegetation, these fish do not disdain and nuts, seeds that fall into the water.
The structure of the jaw
Piranhas are characterized by an amazing structure of the jaw apparatus, perhaps unparalleled in nature. It has everything down to the finest details. The teeth, which are triangular in shape and measure 4-5 mm, are lamellar and sharp, like a razor blade, slightly curved inward. This allows them to easily cut through the flesh of the victim, tearing off pieces of meat. In addition, the upper and lower teeth fit perfectly into the sinuses when the jaw is closed, creating strong pressure. This feature allows piranhas to bite through bones. When closing, the jaws close like a trap. According to the latest research by scientists, the bite force is 320 newtons and has no analogues in the animal world. The jaws of a piranha exert about 30 times its weight when biting.
Where do piranhas live?
These are the inhabitants of freshwater reservoirs in South America. The Amazon basin contains a fifth of all fresh water, this river is full of a variety of fish. Piranhas live along the entire length of the river and are the subject of many legends and stories of local residents. The floodplain of the river occupies vast territories, most of which belongs to Brazil, but also to Ecuador, Colombia, Bolivia and Peru. Piranhas also feel great in other rivers, their habitat on the territory of the South American mainland is very large.
Recently, in home keeping and breeding has becomethis fish is very popular. The piranha in the aquarium will grow smaller than its natural size and lose some of its aggressiveness. Surprisingly, with such a menacing appearance, they become shy in confined spaces and often hide in artificial shelters.
All piranha fish are united in one family and are divided, according to zoological classification, into three subfamilies.
Myelin subfamily
Myelins are the most numerous group, it unites seven genera and 32 species. These are herbivorous and absolutely harmless piranhas (photo). Fish eat plant foods. The coloration is quite varied, depending on the species. The body shape is characteristic, laterally compressed and high. Juveniles are steely silver with varying degrees of mottling, which darkens to chocolate gray as they grow. Sizes vary from 10 to 20 centimeters. Many representatives of this subfamily are bred in aquariums. They need a large amount of water and enough space to hide, as they are quite shy fish. Aquarium piranha from the myelin subfamily will do well in water temperatures of 23-28 degrees, and the daily diet should include lettuce, cabbage, spinach, peas and other vegetables. Some species even feed on nuts in natural conditions, easily cracking strong shells with their powerful jaws.
Black pacu is the brightest representative of myelin
Black Pacu (orAmazonian broadbody) is the most famous representative of the Myelin subfamily. In addition, it is also the largest: its dimensions range from 30 centimeters to one meter or more, and for all that, it is not a predator. The coloration of adults is rather modest, brown-brown, but the young are silvery in color with a large number of spots throughout the body and bright fins. The meat of the Black Pacu has good taste and is used by the locals. These are commercial piranhas. Aquarium conditions are also quite suitable for them, but the size of the fish will be somewhat smaller than in nature, on average about 30 centimeters, life expectancy - within 10 years or a little more. Keeping this species requires a large aquarium (from 200 liters) and good care.
Catoprionin subfamily
This subfamily is represented by only one species - the flag piranha. The fish are quite harmless and lead a semi-parasitic way of life, their main food is the scales of other fish, although the appearance of these aquatic inhabitants is quite sinister, and they are not inferior in severity to their carnivorous counterparts. The shape of the flag piranha is diamond-shaped, flattened laterally. The color of the scales is gray-green with a silvery sheen. A distinctive feature is the presence of a red spot on the gill covers. The extreme rays of the anal and dorsal fin are strongly elongated, while the caudal fin has a black root. The sizes are small, only 10-15 cm.
This fish, similar to the common piranha and is its closest relative, in its main diet (60%)has plant food, and only 40% are small fish. But it still needs to be kept separately from other fish, otherwise very small ones will be eaten, and large ones risk being left with damaged fins and partially without scales. As animal food, you can use small shrimps or fish, earthworms, and vegetable food - spinach leaves, lettuce, nettles and other greens.
Serrasalmina subfamily
These are the very ruthless predators, the subfamily is represented by only one genus and 25 species. They all eat animal food: fish, animals, birds. The size of piranhas of the Serrasalmina subfamily can reach up to 80 cm in size, reaching a weight of up to 1 kg. This is a real threat to animals (not to mention fish), which can exceed them several times in size, but this does not stop piranha. The appearance of small predators is really formidable: the lower jaw protrudes significantly forward and is slightly bent upwards, the eyes are bulging, and a rounded flat body shape is characteristic. In water bodies, they prefer to stay in flocks, but when attacking a prey, they act independently of each other, so it cannot be said that these are close-knit group fish. Piranhas react to movement in the water, this attracts their attention. When one of them finds a victim, the rest immediately flock to the place. Moreover, there is an opinion of zoologists that piranhas are able to make sounds, thereby transmitting information to each other. A flock of piranhas can leave only bones from an animal in a few minutes.
Information that they are able to feel the blood on a decentdistance from the victim, - true. Piranha fish live in the murky waters of the Amazon, and it is natural that they had to adapt to conditions of poor visibility, as a result - a well-developed sense of smell. Piranhas are really attracted to blood, this is a signal of the appearance of the victim.
Besides, they do not disdain carrion and even their sick or weakened brethren. For animals and humans, only a few species pose a real danger.
Common piranha
The most famous representative, around which the conversations do not cease, is the Common piranha. The length of an individual of this species can reach up to 30 centimeters, but mostly they are the size of a human palm. Common piranhas (photo of the fish below) are greenish-silver in color with many dark spots all over the body, and the scales on the abdomen have a characteristic pinkish tint. They live in packs of about a hundred individuals.
In recent years, common piranhas are very popular in home keeping. Aquarium conditions contribute to the weakening of aggressiveness. But the aquarium still needs a separate one.
Black piranha
This is another species from the Serrasalmina subfamily, very common in nature and popular in home breeding. Habitat - Amazon and Orinoco rivers. The shape of the body is diamond-shaped, and the color is dark, black and silver. In young fish, the abdomen has a yellow tint. Black piranha is an omnivorous predator, everything is suitable for the diet: fish, arthropods, birds or animals that accidentally fell into the water. Such indiscriminate eatingled to their fairly high numbers in the waters of the Amazon. Although in terms of aggressiveness, the species is inferior to the same ordinary piranha. An aquarium for such fish needs a large one, more than 300 liters. The complexity of breeding lies in the aggressiveness of piranhas in relation to each other. Reproduction is possible if the aquarium members of the family eat properly, with an abundance of animal food, they are obese, which can be a significant obstacle to the appearance of offspring. In the photo - a black piranha.
Myth one: piranhas attack humans
It is unequivocally difficult to judge this, since the data are very contradictory. Many scientists and zoologists who have spent more than one year on the Amazon have never witnessed an attack, in addition, they themselves, endangering themselves for the sake of the experiment, swam in the muddy waters of the river, where piranhas were caught a few minutes before, but there were no attacks. followed.
For a long time there was a story about a bus with local residents, which moved into one of the tributaries of the Amazon, and all the passengers were literally eaten by piranhas. The story really took place in the 70s of the last century, 39 passengers died, but one managed to escape. According to eyewitnesses, the bodies of the victims were indeed badly damaged by piranhas. But it is not possible to judge whether this was an attack and whether it is the cause of death.
There are reliable sources of bites on the beaches of Argentina, when the fish were the first to attack. But these were isolated cases. Zoologists explain itthe fact that piranhas, whose spawning just begins at the height of the beach season, build their nests in shallow water. Therefore, this behavior of fish is quite natural: they protected their offspring.
In addition, piranhas are most dangerous to humans and animals during the drought period, when the water level in the rivers reaches its minimum, which affects their diet: there is less food. Local residents know about this and do not enter the river at this time. The safest is the rainy season, when the rivers flood.
Myth two: piranhas attack in packs
There are many stories about the terrible attacks of a whole flock, all this is fueled by numerous feature films. In fact, large individuals do not prowl in search of prey in the river, they stand in one place, as a rule, in shallow water. The fish waits for its prey, and as soon as this victim appears, the piranha goes to the right place. Attracted by the noise and the smell of blood, the others rush there as well. Piranhas gather in flocks not to hunt for prey, but to defend themselves from the enemy - many scientists believe so. It would seem, who can harm them? However, even such a predatory fish has enemies. Piranhas, gathering in flocks, defend themselves from river dolphins that feed on them, and for people they are harmless and quite friendly. In addition, among the natural enemies of piranhas are arapaima and caimans. The first is a giant fish, which is considered almost a living fossil. With amazing, heavy-duty scales, it poses a real threat to piranhas. Fish, found singly, instantly become a victim of arapaima. The Caymans aresmall representatives of the order Crocodiles. Zoologists have noticed that as soon as the number of these caimans decreases, the number of piranhas in the river immediately increases.
Myth three: piranhas appear in Russian waters
Incidents did take place, but this is the result of either the behavior of sloppy aquarium fish lovers, or deliberate launching into a reservoir. In any case, worry is in vain. Although piranhas perfectly adapt to any conditions, the main factor for their successful existence remains the same - a warm climate and water (within 24-27 degrees), which is impossible in our country.
Of course, these are predatory fish. Piranhas are dangerous and very voracious, but still stories about them are often too embellished and far-fetched. The indigenous population of South America has learned to coexist next to piranhas and even made them an object of fishing. Nature has not created anything useless: if wolves are forest orderlies, then piranhas perform a similar function in water bodies.
