Thanks to Hollywood, each of us imagines a shark as a ruthless killer of enormous proportions, day and night chasing careless swimmers. Let's not argue, there are grounds for such an opinion: sharks are still predators, and hunting for game is a natural behavior for them. However, there are varieties of sharks that are absolutely not dangerous for large creatures, which can be safely attributed to humans. And there are predatory fish, which in many ways (at least in the diet) are similar to whales.
And the size of sharks in the generally accepted view is not so clear. There are species of sharks reaching a length of 11-15 meters (in particular, large specimens of a whale shark). And there are 15-centimeter babies that are dangerous only for small fish and diligently escape from most of the larger counter organisms.
Shark in general
No matter how different the representatives of this superorder are among themselves, all sharks have common features in structure, physiology and behavior:
- The skeleton of these creatures is formed not by bone tissue, but by cartilage, which makes sharks lighter, nimble and mobile.
- They all lack a swimming bladder, without which most of the other fish cannot exist.
- They are covered not with scales, but with skin, which is very tough, equipped with the smallest sharp cloves. Many people and marine animals died when meeting sharks not from their teeth, but from accidental contact with the skin.
- Among these predators there are species of sharks that do not spawn, but are viviparous. However, for those who have followed the breeding path more traditional for aquatic inhabitants, the intermediate stage of development is not caviar, but rather some kind of eggs: there are very few of them (from 1 to 3), and they are protected by a very strong shell-shell. Moreover, from this repository appears not a fry, but a formed cub. So specifically for the sharks, the new term “egg production” was coined.
- In many species of these fish, their teeth grow in several rows (from 3 to 5), which number up to 3 thousand canines and are constantly updated. Caries is not terrible for these creatures!
A separate question is: how many species of sharks are known to science. The fact is that many of them have only a dozen or two representatives. And some are completely presented in a single instance registered by scientists. In principle, in the world there are 150 species of sharks - from those that have been encountered by oceanologists in many countries, and more than once. Given the species that are becoming extinct (mainly due to hunting for ocean predators), their number can be safely increased to 268. Some researchers believe that the number can be raised to 450, but the remaining species of sharks are known only from the evidence of biologists accidentally encountering them.
Weird sharks
This "tribe" impresses scientists with its dissimilarity, and sometimes with the antagonism (except for the menu), which is shown by individual species of sharks. So, the fish are supposed to have a torpedo-like body shape - this facilitates hunting in the aquatic environment. But there are some types of predators described, similar to stingrays or flounders: they are looking for prey near the bottom. And others have a flat and very wide muzzle. Still others boast a sharp nose. But at the same time, all species of sharks possess the basic characteristic features.
Another feature: having sharp teeth, often continuously growing, predator fish use them only for attack. That is, they grab their prey and tear it, but do not chew. That's why her entire oral filling consists exclusively of fangs - the shark has no chewing teeth.
Species of sharks: names of the most dangerous for humans
The abundance of these predators by name is very difficult to list. Some species of Russian-language analogues have no names at all, there are only Latin names for each species of sharks. For children and adults, however, it is more important to know about the most dangerous of them, in case you have to be near the ocean, where such creatures are found.
The largest, scary and famous shark is the great white one. It accounts for half of all human deaths from shark attacks, and three quarters of all attacks of these animals. The only consolation: this predator prefers sea lions, carrion, whales and seals. If you do not provoke it and do not get hurt in the water before the blood, it will float by.
Second place for the tiger shark. She got the nickname thanks to the vertical stripes on her body. And the second reason was the bad character - the shark is aggressive and omnivorous. Again, without provocations, he will not chase a person, although he can feast on him, just out of habit to pick up everything that meets on the way.
Ocean shark bull is recognized as the most aggressive of all representatives of the superorder. Worst of all, it can go into the mouths of large rivers. It rushes at everything that moves, it can attack in shallow water. So if the resort is warned that representatives of this species of sharks are seen in the water, it would be wiser to get to the beach. And do not enter until allowed.
Horror of the seas: cigar shark
From the point of view of curiosity, it is much more interesting to consider little-known species of sharks. There is a fish from this tribe, whose length is only 42 cm, and the appearance is scary and ridiculous. The long teeth of a cigar shark make it look like a sea bulldog. But the predator itself is terrible: it can kill an ocean inhabitant five times larger than itself.
Biologists call such creatures ectoparasites. He bites into the victim unnoticed by herself and eats away a significant piece of the “carrier” flesh. Large individuals survive after the attack, but those fish / animals that are comparable to or slightly larger than the aggressor are dying.
The cigar was first caught in the Gulf of Mexico in 1964, and since then only a dozen of its relatives have fallen into the hands of ichthyologists. So those who have already seen some sharks, this is hardly familiar.
Angel Shark: Disguise Genius
This species of sharks has certain reasons to be called that. And not at all because of the flexible character: the fish just looks innocent enough. The diver who met with her will be sure that he has come across a ramp. "Angels" move nearby, hunt from ambush, and they can wait in it for hours or even days, while maintaining complete immobility.
Fortunately, the "angels" are indifferent to people and do not prey on them. But if you step on a lurking hunter (and even more so try to catch), he will respond with a lightning and ruthless attack. Wounds will not be fatal, but bloody, painful and require the intervention of a surgeon.
