Dangerous and harmless shark
When you hear the word “shark” we present a huge toothy fish, predator and ruthless killer. But, it turns out that among 350 species of sharks are not dangerous more than 50 species – the other sharks are quite harmless. Many sharks are fairly small, not more than two feet long, and only attack clams and crabs, and the largest sharks in General are confined to the plankton.
Sharks belong to the cartilaginous class of fishes. Sharks superorder includes 8 units and approx 20 families. All sharks are carnivorous, and most of them are predators. Sharks can live in the open sea and hunting on mammals and large fish, and can live near the seabed and collect benthic animals. The difference in lifestyle gives rise to the difference in appearance. “Shark” appearance sharks are from the family of Requiem sharks: blue (3.8 to 6 m) and soup (2 m) sharks, as well as the setting in water of Mediterranean mackerel shark and shark-Mako 2 (3,4-4 m) from the squad of lunoobraznogo.
Blue and soupfin sharks are kept open sea and hunt for fish and cephalopods. Blue sharks often accompany court Pobjeda thrown overboard the waste. It is believed that the blue shark dangerous to humans, but as in the open sea, where it is more usual, little swimmers, and attacks are infrequent. Ethanol is much more dangerous to the man himself. Both of these sharks are the target species, and shark fin soup cook a delicious soup. Sharks-Mako, on the contrary, very dangerous. Aggressive and armed with several rows of razor sharp teeth, they often attack boats in the open ocean and swimming up close to shore to attack swimmers.
Benthic sharks have different habits and a different appearance. For example, benthic lifestyle had transformed European marine angel 3 (2,4 m 72 kg), the shark from the squad scutineering, the family of sea angels. The body of this Mediterranean sharks are much flattened and have large pectoral and pelvic fins located on the sides of the body.
At the bottom of the cat and weasel sharks body is not flat, but strongly elongated. The small dorsal fins are heavily tilted back and his mouth is located at the bottom of the muzzle. Light gray or yellowish color, often with spots, masks these sharks in the color of the bottom. Family gray, cat and weasel sharks belong to the order of carcharhiniformes. The smallest sharks are United into the family katrenova or spiny sharks. They are called spiny because in front of dorsal fins they have sharp thorns. In the Mediterranean, several species of old-fashioned recourses. Shark meat is tender and tasty, lacking typical of other sharks unpleasant smell.
But on the appearance of sand tiger shark (3 m) from the squad lunoobraznye benthic life is almost not affected. “Shark” appearance concedes slightly flattened head and slightly shifted back to a small dorsal fins.
From large sharks in the Mediterranean sea is home to a six-gilled (to 5 m) and sevengill (2 m) sharks from the squad mnogoelektronnykh. Both sharks are found both in shallow waters and at depths (sixgill up to 1900 m). In the Mediterranean sea, these sharks are not dangerous, but the Australian relatives of the sevengill sharks, which can grow up to 4.5 m, often attack people.
Cartilaginous fish with highly flattened disc-shaped or diamond-shaped body are United into a super-squad the stingrays. The rays, unlike the sharks, with Gill slits on the sides of the body and on the ventral side, and the edges of the pectoral fins fused with the head and sides. Most of the stingrays leads a benthic life. More than other stingrays sharks stingrays similar guitar from the squad rachiopathy, family rolevyh rays. Body shape these rays resemble the guitar or violin (in France they are called sea violins). Ordinary guitar Stingray is most commonly found in the Adriatic sea and in Sicily. This manta ray swims slowly near the bottom or is buried in the sand. He eats small benthic inhabitants, including oysters. Voracious scat eating these shellfish in such quantities that a substantial damage to the breeders oysters.
Bad reputation is Gnus or ordinary electric ray (1.8 m, 90 kg) from the squad stingrays. A resident of coastal shoals, Gnus burrow into the sand and becomes almost invisible. Woe to the bather inadvertently step on a Stingray, strong electric discharge will discourage carelessly walking over the sand. With caution should be treated to the sea Fox (70-125 cm), the caudal peduncle which is studded with barbed spikes near. If stepping on it, it will cause painful attacks spiked tail. Sea Fox belongs to the family of diamond stingrays, the stingrays squad remotely.