Just as lion is called the king of beasts, the same way shark can be called the king of fishes. It is the fastest and the most dangerous fish in the sea. It is also the largest of all fishes, ranging from one foot to over 50 feet in size. Another reason for calling it the king is that it belongs to one of the oldest groups of creatures alive in the world today. Some fossils of sharks are believed to be around 250,000,000 years old.
A shark is a saltwater fish that belongs to the class Chondrichthyes. Its skeleton is made up of cartilage rather than bones. Its skin is covered with many small scales which are like sandpaper. There are about 400 species of sharks in the world. The dog-fish shark grows up to around 3 ft. in length. It feeds on small fish and invertebrates. The whale shark, the largest of all fish, can reach about 50 feet in length. It is the least dangerous. These sharks have many razor-sharp teeth. The great white shark, the greediest monster, swallows its prey whole. The remains of big animals, such as seals, dolphins and smaller sharks have been found in its stomach.
A shark will eat almost anything found in the sea from the tiniest sort of sea creatures to other sharks, turtles, seals or dolphins. They have been known to swim up rivers and attack crocodiles, horses and elephants which might have waded into the water. They are also found to attack people swimming in the sea. When in pursuit of their prey, they can move very fast. They follow the ships to feed on the waste food thrown overboard from the kitchens of the ships. Some sharks live and hunt alone, while others prefer to roam the seas in packs. Most of the sea beaches in Australia and South Africa are protected from sharks by iron-nets and electric barriers, for the safety of the swimmers.
Sharks are caught in large number every year. Their meat is very nutritious and cheap, and can be quite delicious if properly cooked. Their skin is used for binding books and covering boxes, and for making bags and shoes.
The most beautiful shark is the mako shark. It is snow white underneath and brilliant blue on the top. It is very fast and ferocious and a strong fighter when caught alive.