First, they can pick up very slight sounds through vibrations in the water when an object moves. Second, they have sensitive spots on their snouts that look like skin pores, but are really special glands that detect small amounts of electricity given off by animals. Third, they have a powerful sense of smell, so strong that it can pick up one molecule of blood in a million molecules of water. The shark s body is covered with thousands of tiny teeth known as dermal denticles or skin teeth. They point backwards to smooth the water over the shark s body so it can swim faster.
Some sharks deposit a fertilized egg sac on the ocean floor.
It has a strong leathery case that protects the embryo until it is born. In most sharks the eggs hatch inside the mother and the shark gives birth to a live pup. Once born, all sharks are on their own, and are not cared for by their mothers. Sharks are fish because they have gills and get their oxygen from the water. They do not nurse their young.