Thanks to Hollywood, each of us sharkimagines himself as a ruthless killer of enormous dimensions, day and night pursuing carefree swimmers. We will 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, absolutely not dangerous for large creatures, to which you can safely refer a person. 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 conventional view is notso they are unambiguous. There are species of sharks, reaching a length of 11-15 meters (in particular, large specimens of the whale shark). And there are 15-cm babies, dangerous only for small fishes and diligently fleeing from most of the larger counter organisms.
No matter how different representatives of this order are among themselves, all sharks have common features in structure, physiology and behavior:
A separate question is:how many varieties of sharks are known to science. The fact is that many of them number only a dozen or so representatives. And some are even represented in a single specimen registered by scientists. In principle, there are 150 species of sharks in the world - from those that met the oceanologists of many countries, and more than once. Considering the endangered species (mainly due to hunting for ocean predators), the number of them can be safely increased to 268. Some researchers believe that the figure can be raised to 450, but other species of sharks are known only from the evidence of biologists who happened to collide with them.
This "tribe" amazes scientists with its dissimilarity, andsometimes and antagonism (if you do not count the menu), which show some species of sharks. So, a fish is supposed to have a torpedo-like body shape - this makes it easier to hunt in an aquatic environment. But there are some types of described predators, like skates or flounder: they are looking for prey near the bottom. And others have a flat and very wide muzzle. Still others can boast of a sharp nose. But at the same time, all types of sharks are the main 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 all her oral stuffing consists exclusively of fangs - the shark has no chewing teeth.
Abundance of these predators is listed by name verydifficult. Some species of Russian-language analogs of names and does not exist, there are only Latin names for each variety 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 -large white. It accounts for half of all human deaths from shark attacks, and three-fourths of all the attacks of these animals. The only thing that comforts: this predator is more to taste sea lions, carrion, whales and seals. If you do not provoke it and do not get hurt in the water to the blood - it will float by.
Second place behind a tiger shark.She got the nickname thanks to the vertical stripes on her body. And the second reason was a bad character - a shark is aggressive and omnivorous. Again, without provocations, they will not chase a person, although they can regale themselves, simply by habit of selecting everything that meets on the way.
The oceanic sharks are recognized as the most aggressiveof all representatives of an orderly. Worst of all, it can enter the mouths of large rivers. Throws to everything that moves, can attack in shallow water. So if the resort warns that representatives of this species of sharks are seen in the water, it would be wiser to get to the beach. And do not go until you are allowed.
From the point of view of curiosity, it is much more interestingto consider little-known species of sharks. There is a fish from this tribe, whose length is only 42 cm, and the appearance is terrible and ridiculous. The long teeth of a cigar shark make it the likeness of a sea bulldog. But the predator itself is terrible: it can kill an ocean inhabitant once every five times larger than himself.
Biologists call these creatures ectoparasites.He bite into the victim quietly to herself and eat away a significant chunk of "carrier" of the flesh. Large individuals allowed to stand after the attack, but those fish / animals that are comparable to or slightly exceed the dimensions of the aggressor, die.
The first "cigar" was caught in 1964 in the Gulf of Mexico, 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.
This species of sharks has certainthe grounds are so called. And it's not because of the easy-going nature: the fish just looks innocent enough. The diver who meets her will be sure that he has a stingray in his way. Move "angels" nearby, hunt from ambush, and wait in it for hours and even days, while maintaining complete immobility.
Fortunately, to people "angels" are indifferent and on themDo not hunt. But if the hunted hunter to step (and even more so try to catch), he will respond with lightning speed and ruthless attack. The wounds will not be fatal, but bloody, painful and requiring surgeon intervention.
Этот представитель хищнического племени поистине is unique. First, he can swim without harm to himself and live in fresh waters for a long time. Secondly, this shark can lie for a long time at the bottom - and generally prefers to hunt in shallow depths, up to one meter. Third, thanks to its color, it blends beautifully with the surrounding landscape. A man will not eat, but his favorite dog - without difficulty.
Unlike the angel-shark, prefers to avoidcontacts, but the attack responds aggressively. However, they are very few, they are found mainly in the South American waters, so that there is little chance of meeting her.