Bull Shark

Great White Shark

Hammerhead Shark

Nurse Shark

Tiger Shark

http://en.wikipedia.org/wiki/Shark

http://www.flmnh.ufl.edu/Fish/Sharks/sharks.htm

• In some form, sharks have been around for about 400 million years. Even before dinosaurs roamed the earth, sharks hunted through the oceans! They're such good survivors that they've had little need to evolve in the last 150 million years.

• Sharks are from the superorder Selachimorpha. They are fish with a full cartilaginous skeleton and a streamlined body. They respire with the use of five to seven gill slits. Sharks have a covering of dermal denticles to protect their skin from damage and parasites and to improve fluid dynamics. They have replaceable teeth. They are some of the world's most misunderstood predators, as they very rarely attack humans unless intimidated.

• Sharks have the most powerful jaws on the planet. Unlike most animals' jaws, both the sharks' upper and lower jaws move. A shark bites with it's lower jaw first and then its upper. It tosses its head back and forth to tear loose a piece of meat which it swallows whole. A shark may grow and use over 20,000 teeth in its lifetime! Sharks never run out of teeth. If one is lost, another spins forward from the rows and rows of backup teeth.

• Almost all sharks are "carnivores" or meat eaters. They live on a diet of fish and sea mammals (like dolphins and seals) and even such prey as turtles and seagulls. Sharks even eat other sharks.

• Baby sharks are called pups. Just like there are many types of sharks, there are also different ways that sharks come into this world. There are three ways that sharks are born:
  1. eggs are laid (like birds)
  2. eggs hatch inside the mother and then are born
  3. pup sharks grow inside the mother (like humans)

• Sharks can have from 1 to 100 babies at a time, depending on the type of shark. The ones with pups that grow inside the mother have fewer babies at a time than sharks that lay eggs outside the body. Sharks do not care for their babies after they are born, but they do search for a safe place where they can lay their eggs or give birth.