All reptiles are vertebrates, which means they have a backbone.
Reptiles are cold blooded and have either scales or scutes, which are, bony external plates or scales overlaid with horn.
They move by either creeping on their short legs or crawling on their bellies, like snakes.
They have dry, scaly skin.
The most common defense for reptiles is to avoid enemies, if they feel threatened lizards and snakes tend to move away and turtles and crocodiles will tend to sink down in water.
Some reptiles will hiss or make a noise by vibrating their tails, if they feel threatened.