What is shark?

Many people think of sharks as mean and menacing with their pointed snouts, fearsome teeth, and staring eyes. Sharks are skilful predators, but only a few are a danger to people. The 375 or so species of shark range in size from a lantern shark at about 20cm (8 in) long to the whale shark at over 12m (40 ft) long, but half the species are less than 1m (3.3 ft) long. Not all sharks are as streamlined as spinner shark. Angel sharks have flattened bodies, horn sharks are blunt-headed, while bamboo sharks are long and flexible. All sharks belong to one class gristle-like cartilage. Sharks live in the sea, though a few live in or swim into inland waters.