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                 Sharks Are Cartilaginous Fish


The term “cartilaginous fish” means that the structure of the animal’s body is formed of cartilage, instead of bone. Unlike the fins of bony fishes, the fins of cartilaginous fishes cannot change shape or fold alongside their body. Even though sharks don't have a bony skeleton like many other fish, they are still categorized with other vertebrates in the Phylum Chordata, Subphylum Vertebrata , and Class Elasmobranchii. This class is made up of about 1,000 species of sharks, skates and rays.









          There Are Over 400 Species of Shark



Sharks come in a wide variety of shapes, sizes and even colors. The largest shark and the largest fish in the world is the whale shark (Rhincodon typus), which is believed to reach a maximum length of 59 feet. The smallest shark is thought to be the dwarf lanternshark (Etmopterus perryi) which is about 6-8 inches long.












                  Sharks Do Not Have Scales  



A shark has tough skin that is covered by dermal denticles , which are small plates covered with enamel, similar to that found on our teeth.






       Sharks Can Detect Movement In The Water



Sharks have a lateral line system along their sides which detects water movements. This helps the shark find prey and navigate around other objects at night or when water visibility is poor. The lateral line system is made up of a network of fluid-filled canals beneath the shark’s skin. Pressure waves in the ocean water around the shark vibrate this liquid. This, in turn, is transmitted to jelly in the system, which transmits to the shark’s nerve endings and the message is relayed to the brain.












                      Sharks Live a Long Time



While nobody seems to know the true answer, it is estimated that the whale shark, the largest shark species, can live up to 100-150 years, and many of the smaller sharks can live at least 20-30 years.

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