Reptiles (British) - What is a Reptile?

Of the living groups of reptiles (tuatara, crocodilians, turtles, snakes and lizards) only snakes and lizards are represented in Britain. Unlike amphibians, reptiles have no larval forms. The young are either born alive (viviparous) like the adder and common lizard, or hatch from eggs (ovoviviparous) like the grass snake and sand lizard. Reptiles bodies are covered with scales, or bony plates (such as the shell of a tortoise). Lizards periodically shed their skins in flakes, while snakes cast off theirs as a single slough. They are cold blooded and need an external source of heat, such as the sun, to regulate their body temperature.