Sharks

I want to talk about sharks but in a different way that we always hear specially in Hollywood films, that sharks are dangerous but we must know about this animal many things like not all species of sharks are dangerous really its just five kinds and the most popular is the white shark that really kill humans.

While some sharks (like the Great white or the Gray Reef shark) turn aggressive prior toan an attack, they arch their back and throw back their head. This places their mouth in a better position for taking a big bite. They also move their tail more acutely (probably in preparation for a chase). Sharks attack fewer than 100 people each year. Many more people are killed by bees or lightning.

The sharks that are the most dangerous to people are the great white shark, the tiger shark, the bull shark, and the oceanic whitetip shark. The bull shark is the most frequent attacker of people as it swims in very shallow waters where people swim and is a very plentiful shark Sharks are a type of fish with a full cartilaginous skeleton and a steamlined body. They respire with the use of five to seven gill slits. Sharks have a covering of dermal denticales that protect their skin from damage and parasites and improve fluid daynamics they also have replaceable teeth. shark teeth are prized by collectors for their beauty, and because they are surviving relics of ancient sharks that are now extinct. Sharks range in size from the small pygmy shark, Euprotomicrus bispinatus, a deep sea species of only 22 centimetres (9 in) in length, to the whale shark, Rhincodon typus, the largest fish, which grows to a length of approximately 12 metres (39 ft) and which, like baleen whales, feeds only on plankton, squid, and small fish through filterfeeding. The bull shark, Carcharhinus leucas, is the best known of several species to swim in both salt and fresh water and in deltas.

Sharks have existed for over 350 million years. They evolved over 100 million years before the dinosaurs did. This was long before people evolved. Most fossil evidence of early sharks is from fossilized teeth and a few skin impressions. Cladodonts, primitive sharks, had double-pointed teeth, were up to 6 feet (2 m) long lived about 360 million years ago , they ate fish and crustaceans. sharks eg angel shark have flattened bodies that allow them to hide in the sand of the ocean bed. Some sharks have an elongated body shape ( eg cookiecutter sharks and wobbegongs).Sawsharks Sawsharks have elongated snouts, thresher sharks have a tremendously elongated upper tail fin which they use to stun prey, and hammerheads have extraordinarily wide heads. The globin shark has a large, pointed protuberance on its head; its purpose is unknown.

finally i want to add that the reason that sharks attacks human because our shape looks like seal in the water when we are swimming and also the boats, and seal us the delicious feed to shark.