The head of a sand tiger shark. Although fearsome-looking, it is of little danger to humans, preferring to feed on fish, rays,...Read More >>The head of a sand tiger shark. Although fearsome-looking, it is of little danger to humans, preferring to feed on fish, rays, crabs and lobsters. It can hover motionless in the water by swallowing surface air, and achieving buoyancy. Sharks are a kind of cartilaginous fish: they have skeletons made of soft cartilage (gristle) rather than rigid bone. They live in all the world’s oceans. Sharks are mostly predators, although the largest kinds of all, including the whale shark and basking shark, feed only on krill or small fish. Sharks rely on their sense of smell and their ability to detect movement in the water to hunt their prey. They also have special sense organs that sense electrical currents made by the muscle movements of prey. Many sharks have large, razor-sharp teeth set in rows.
Skin and bones
A shark’s skin feels like sandpaper to touch. It is covered by tiny, teeth-like scales called dermal denticles. Each scale is even made of dentine with an outer covering of enamel—just as teeth are. The covering makes the shark more streamlined in the water.
About 50 to 70 shark attacks are reported every year. Of these, less than four attacks each year on average prove to be fatal.
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