The shark’s biggest enemy are humans because people kill sharks to get their fins to eat. 73 sharks are killed in a year! People are killing sharks because they get their fins, liver, oil pills and also they make a skin care!
The habitat of sharks not only takes place in different levels of the ocean, but also is restricted to different areas. This is based on the activities that are needed, whether they need fresh or salt water, seasonal changes that are needed and temperature of the ocean. Typically, most sharks will be based around the warmer parts of the ocean, ranging from the central regions of the Americas to places around the tips of Africa, Australia and India. There are also cold water sharks that will be further south or north in the ocean.
Some sharks species live from 20 to 30 years. Some scientist think that the great white shark could be up to 100 years, but it has not been proved. The tiger shark could be between 30 and 40 years. Some well known shark species like the mako shark, the lemon shark and the bull shark are still unknown. The whale shark can live up to 100-150 years. Scientifically there is no way to determine the life span of sharks.
The largest whale shark registered weight was 47300 lb or 21.5 tonnes. From there, weights vary according with the specie. Male bull sharks weight around 200 lb while female bull sharks can reach 700 lb. The largest tiger shark captured weight was 3,360 lb. The great white shark weight ranges from 1,500 lb. to 2,500 lb. although there are larger sharks of this specie.
Shark skin is a sandpaper like surface which plays an important role in shark efficient movements. Internally, this skin is composed by millions of tiny scales which have form of teeth and form a tough mesh of a protein called collagen. This meshwork covers muscles and have them attached in a way that creates an armor which acts like an external skeleton.