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Fishin' for Facts: Sharks

Scientific name:      Class Chondrichthyes

                                Superorder Elasmobranchs

There are approximately 450-500 different kinds of sharks. The largest is the whale shark, which can reach lengths up to 55 feet long. One of the smallest species is the dwarf lantern shark which is only 6 to 8 inches long.   

What they eat depends on the kind of sharks. Some eat crustaceans, mollusks, or small fish. Others eat larger fish, squid, and octopus. Others may eat dolphins, seals, sea lions, penguins, other sharks, and whales. Some are even plankton eaters.

Sharks have been around a long time - longer than dinosaurs. Fossil evidence shows sharks (relatives of today's sharks) existed 400 million years ago. The shark families that exist today were around at least 100 million years ago.

Sharks are found all over the world, even in some freshwater rivers. Depending on the species of shark, some have live birth, others hatch from an egg. Sharks don't stay with their young. As soon as the egg is laid or the pup is born the female leaves.  (Leviathan Link: Shark Reproduction)

Some sharks travel with other sharks (in schools)  others are solitary. This also depends on the species of shark. 

Sharks are extraordinary predators. To find food a shark uses its hearing and sense of smell to locate prey (lunch).  As it gets closer the lateral line helps. The lateral line is a fluid filled canal that runs along the side of a shark's body. The movement of the small sensory hairs in the lateral line feel vibrations and movements in the water. 

Moving closer still,  it uses its eyes to track prey.  If the water is clear enough a shark may be able to see up to 50 feet away (15 meters).

To zero into its prey, a shark relies on Ampullae of Lorenzini.  Ampullae of Lorenzini  pick up electrical currents in the water.  Anything alive gives off an electrical current. 

No bones about it... Sharks do not have bones.  That doesn't mean they do not have a skeleton, though.  A shark's skeleton is made of cartilage (like in your ears and nose bridge).

 

Do sharks and dolphins fight?  Find out...

What about shark reproduction?