Sharks are meat-eating sea fish. Most have sleek bodies and rows of sharp teeth. There are about 375 types, of different shapes and sizes, living in different parts of the world. The dwarf shark is only ten centimetres long, while the whale shark, the biggest of all fish, is 15 metres.
How old are sharks?
Fossils show that sharks appeared more than 350 million years ago, long before the dinosaurs. Megalodon was a huge shark which hunter large prey and probably ate shellfish too. Its teeth were about nine centimetres long.
Amazing! Sharks become sluggish in cool water, and so most prefer to live in warm seas. But the huge Greenland shark, six metres long, enjoys icy water. It lives in the North Atlantic, hunting for fish and seals beneath the pack ice.
Is it true? All sharks are dangerous.
No. In the order of dangerous sharks, the great white is most feared by people. But most sharks are harmless to us, and will only attack if they are disturbed. Other dangerous sharks include the tiger shark, mako, bronze and black-tipped whalers, and hammerhead.
Are sharks different from other fish?
Sharks, and their relatives the skates and rays, have skeletons made of rubbery cartilage. Other fish have skeletons made of bone. A shark’s gill slits are not covered like other fish, but are in a row behind its head.
Picture Credit : Google