Reptiles are cold blooded vertebrate animals. Many characteristics define Reptiles, some of which are dry scaled skin, internal fertilization, and three to four chambered hearts. They inhabit many environments. But most, channeled by cold bloodedness, are confined to warmer habitats. Reptiles may be aquatic, semi-aquatic or terrestrial, as well as arboreal.
Reptiles range in size considerably.
The longest reptile is the Reticulated Python, reaching 33 feet in length. The heaviest living reptile is the Leather Back Sea Turtle, which has attained 1,600 pounds in weight. The smallest Reptile is possibly the Dwarf Gecko that reaches only about 1.3 inches in length. The Reptilian skull ranges from the reduced, loosely joined, or kinetic skull of snakes to the large, solid skull of the crocodiles.