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sharks and whales
Transcript of sharks and whales
About 350 different kinds of sharks are already known to mankind, but, researchers are of the opinion that there are other sharks that have not been discovered as yet.
A shark has two dorsal fins on its back, one beneath its body, which is called the pectoral fin (All species do not have that!) and the tail which is the caudal fin.
A shark does not have a single bone in it body, instead it has a skeleton made up of cartilage.
Most sharks live for about 25 years, while some of them can live to be a 100 years too.
A shark takes great care of itself, and are strong and health creatures.
Not all species of sharks are required to be in continuous motion to breathe.
Sharks need to keep on moving to stay afloat.
A shark's teeth are usually replaced every eight days.
Some species of sharks shed about 30,000 teeth in their lifetime.
Sharks do not sleep in the same way as humans. Even if they seem to be sleeping they are not, instead they are just resting.
As sharks never get cancer, their cartilage is being studied in the hope of developing anti-cancer drugs.
Sharks are considered one of the best hunters in the world. Their little pups go out to look for food too.
A shark's skin is covered by small, razor-sharp teeth called denticles. These can be removed from the shark's body. Once removed, the remaining skin is made into strong leather.
Some sharks lay eggs, while most of them give birth to babies. The Hammerhead and Tiger shark can have as many as 40 babies at one time, while the others can have six to twelve.
Most kinds of sharks can swim up to 20-40 miles per hour. The Mayo shark is said to be able to swim at more than 60 miles per hour.
One good meal is enough to satisfy a shark's hunger. The meal can last a shark for a long period because it uses very little energy to swim.
Out of all the people a shark attacks, more than 90% of them survive.
Sharks are said to attack more women than men. The reason is still a mystery.
In the past, dried shark skin (shagreen) was used as sandpaper. In countries like Japan and Germany, shark skin was used on sword handles to get a non-slip grip.
Until 1950, sharks were hunted for Vitamin A. After that period, a synthesizing method was developed.
The Whale shark is considered the biggest fish in the world.
The Whale shark is about 90,000 pounds in weight.
The Basking shark is the second largest, it is as long as 40 feet.
Bull sharks are able to bear a wide range of salinity. They are found in freshwater rivers and lakes in South America and Africa.
The Pygmy shark is about 11 inches in length.
The Dwarf shark is as tiny as you hand, while some Whale sharks are as large as a bus.
The Dogfish sharks are so named, because they attack their prey like a pack of wild dogs.
The modern shark has more biting force because of its protrusile jaw, which provides it with more biting force.
Great white sharks can grow about 10 inches every year, thus, they grow to mature lengths of 12 to 14 feet.