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Marine Life: Shark
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The ultimate ruler of the seas, there are more than 460 species of sharks and they are found in waters all over the globe. The movie JAWS had portrayed the great white shark as a bloodthirsty monster that preys on humans, but in reality, shark attacks are rare. These fish have been around for 350 million years and are among the most successful group of fish, having remained virtually unchanged in physiology for 70 million years. Sharks are also incredibly diverse and adaptable.
Sharks live all around the world, mostly in salt water, but some can live in fresh water. They live in tropical to polar seas, in deep or shallow water. Many juvenile sharks live in estuaries.
Sharks feed on a variety of animals: fish, rays, seabirds, crustaceans, sea turtles, and sometimes other sharks. The larger sharks also eat sea lions, elephant seals, and dolphins. They may attack humans, but don't eat them.
Sharks are social animals and live and migrate together. This social behavior has allowed them to develop a very complex body language. Their social interactions are peaceful (even those of the great white), with every member of the group aware of its rank in the hierarchy.
Sharks have babies in two ways: some lay egg cases and others give birth to live pups. Once born, they are on their own, receiving no parental care.
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Sharks are fish, but unlike fish, which are bony, sharks are made of cartilage, a strong and flexible tissue.
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