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Shocking Shark Facts

A grey reef shark at Ducie Atoll, part of the Pitcairn islands.

A grey reef shark at Ducie Atoll, part of the Pitcairn islands. (View larger version)

Photograph by NGT / Enric Sala

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  • The diversity of sharks is immense; there are 400 kinds of shark species in our seas!

  • Sharks were swimming in the ocean for more than 200 million years before dinosaurs roamed the planet.

  • Unlike humans that have five sense, sharks have a sixth sense that is known as electrosense. This means they can detect very minute fields using special organs called Ampullae of Lorenzini, which are little gel filled pores that can actually conduct electric currents. There is a little nerve at the base of the pore that transmits that information to the sharks brain. This gives the shark an added ability to pick up electrical signals from potential prey.

  • A shark has the ability to detect very slight pressure changes in the ocean by using a set of specialized cells called the lateral line. They are full of tiny little hairs that can detect very slight changes in water movement.

  • The shark has no bones in its body! instead it has a light-weight, elastic cartilage skeleton that makes it one of the most flexible animals on earth. The cartilage also reinforces the fins to help them slice through the water.

  • The tail fin is the powerhouse fin to a shark. In slow swimming, bottom dwellers' upper part of the tail fin is larger than the lower. Fast oceanic sharks have almost perfectly symmetrical tails providing maximum thrust.

  • Great whites are the largest predatory fish on earth. They grow to an average of 15 feet (4.6 meters) in length. Some specimens have been recorded to exceeding 20 feet (6 meters) and weighing up to 5,000 pounds.

  • One of the most interest things about the great white shark is its ability to elevate its body temperature higher than its surroundings. Most sharks cannot do that. Great Whites can produce their own heat and their body temperature adjusts according to their environment. Officially the term is endothermic poikilotherm.

  • The whale shark grows to be forty feet long and over 20 tons. It’s the biggest fish in the world, they grow to be about the size of a school bus.

  • Tiger sharks have often been called the "trash cans" or "garbage cans" of the sea. They get very interested in shiny objects and they’ll eat just about anything. Secondly, only to great white sharks in human attacks, the tiger sharks can be more dangerous as they are not as willing to leave an unfinished meal.

  • Sharks can put their digestion on hold, storing a meal in their stomach for months if they have to. If they bite off more than they can chew, turn their stomach inside out, wash out the contents and start again.

  • A shark can go through 30,000 teeth in a life time.

  • All sharks are well protected – covered in tough, thick-skin composed of a complexly criss-crossed mesh work of tough but springy fibers made of a protein called collagen. It offers the shark great protection against the elements and any predators.

  • It’s believed ancient sharks had more gills than modern ones do today.  Most sharks have five gills.The seven gill species is tied to those from the age of dinosaurs, which is 35 million years older than the great white.  The seven gill species is one of the oldest species of shark still alive today.

  • Sharks reproduce in a variety of ways. Some of them will actually lay eggs and those eggs will develop outside of the female and will eventually hatch into the environment. Other sharks will have the eggs developing inside of them, but then they will give birth to live young.  Some sharks are completely different from other fish because they will actually have a placenta, just like a mammal does, where there is a direct connection between the developing embryos and the mum and then they will also give birth live.
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