Have you seen Jaws, the famous film about the Great White Shark? For an hour and twenty minutes of the film the shark isn’t seen except for bits and pieces and shadows underwater. But when it suddenly appears above the water for the first time, even grown-up people scream and those who have a poor heart reach for their nitroglycerine pills.
Sharks are probably the most feared of all sea animals. There are more than 350 kinds of sharks in the waters of the world. But, scientists say, only 30 species are dangerous to man. Of these 30 five species are known as especially voracious man-eaters: the Great White, the Tiger Shark, the Hammerhead, the Bull Shark, and the Whitetip Shark.
Though shark attacks are rare, they are always sudden, deadly and dramatic. Sharks live in oceans throughout the world but are usually found in warm seas. Some species, however, prefer fresh water and can be met in rivers and lakes.Sharks are remarkably successful animals. They are fast and strong. They are wonderful swimmers. They have very few parasites and are hardly ever ill. They have almost no enemies except other sharks.
Though they are undesirable animals for swimmers, water-skiers, windsurfers and divers, sharks play an important ecological role.
Unfortunately, there are many things we do not know about sharks. We do not knew how long they live and how much food they need to stay alive. There are still undiscovered species in the deep waters of the world ocean.
It’s hard to study sharks at sea, and it’s still harder to keep big sharks alive in a tank.
Some people think that, all sharks are big, but this is not true. Some kinds of sharks are no bigger than your hand. The smallest shark is about 16 centimeters long and weighs about 28 grams.Sharks swam in the sea long before dinosaurs walked the earth — more than 400 million years ago. There are no more dinosaurs left on our planet, but there are still plenty of sharks.
What makes a shark a shark? Among other features, it has a cartilaginous skeleton lighter than bone, and skin covered with tooth-like scales called denticles.
Besides the five senses that humans possess, sharks have the so called ampullae of Lorenzini, electro-receptors so sensitive that they can detect fields as weak as five-billionths of a volt per centimetre.
Different sharks have different habits. Some kinds live in the depths of the ocean and are very seldom seen. Others are found near the surface. Some species of sharks live in coastal waters, but others dwell far out at sea. A few species enter rivers and lakes. For example, Bull Sharks have been captured in the Amazon River in Brazil, in the Ganges River in India, and in the Mississippi River in the United States. Bull Sharks often feed on other sharks and have attacked swimmers.I like little shark.
<span>He insisted to pay / <u>on paying </u>for the meal.
The interviewer started off to ask / <u>by asking</u> me why I wanted the job
I knew I could ask /<u> count on</u> Philip if I needed any help.
We were unhappy in England, and even <u>discussed</u> / talked of emigrating to New Zealand.
I’ve heard a lot about Dr James, and I’m looking forward <u>to hearing </u>/ to hear his talk tomorrow.
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<span>Holidays in Russia is very много.Это Maslenitsa?, Easter ,March 8 , February 23 ,may 9 all it особенные.Конечно we have many holidays that are celebrated by the whole world,and there are holidays that are celebrated only here but in other countries they нет.Та same масленница.Народ rejoiced at what area or simply for some areas,dance,sing песни.А at the end of the harness itself Shrovetide,ie stuffed разодетого in clothes,set fire to his and сжигают.Еще some call it проводсы зимы.9 may to примеру.Это victory day,probably the most significant день.Другие country celebrating can't because it's not as our victory,our holiday.</span>
