Shark

Sharks are a member of Class Chondrichthyes, which includes the ray and skate. In general, sharks are characterized as large, marine, cartilaginous predators. There are over 500 different species and there are many exceptions to the above characterization. Sharks include everything from a thumb sized deep sea species, up to the whale shark, which can get to 60 feet in length but feeds only on plankton like the great whales. Some, like a sub-species of the bull shark, can even live in freshwater lakes. A few of the larger species actually are homeothermic, able to maintain their body temperature at a level above the ocean's temperature.

Most sharks are predatory however and include the well known species such as the great white, mako, blue, hammerhead, and [[bull] sharks among others.