One of the most primitive creatures alive today, sharks have outlasted dinosaurs, Neanderthals and many other now-extinct life forms. Scientists credit the evolutionary success of sharks to several factors. They reproduce in a variety of ways, some laying eggs and others giving birth to live young. In addition, many sharks are resistant to disease. Only humans, who kill them for food and sport, and contaminate their oceans.
Fishing industries harvest large numbers of sharks, finding uses for many parts of their bodies.
Their oil is used in skin creams, lipsticks and other cosmetics, and as a lubricant for delicate scientific instruments. Their large teeth are often made into jewelry and their small teeth are sold as souvenirs. Their flesh is used for human consumption or for pet food. In Japan, their fins are used in shark fin soup, or they are dried and salted. Sharks are sometimes definned and thrown back into the sea to die.