Reptiles include turtles, lizards, snakes, tuatara, and crocodilians. They are cold-blooded with scale-covered skin and breathe through lungs. There are 5 orders of reptiles: Rhynchocephalia containing the tuatara; Chelonia containing turtles; Squamata containing lizards and snakes; and Crocodilia containing crocodiles and alligators. Reptiles range in size from 3 inches to over 30 feet and live on every continent except Antarctica.