What Are the Main Characteristics of Reptiles?

Reptiles are usually found in warmer parts of the world, from prairies to rain forests and deserts to swamps. The only continent in which they don't live is Antarctica. Snakes, lizards, turtles, alligators, crocodiles and tortoises are the most common types of reptile species, and they all share the same main characteristics.

  1. Cold-Blooded

    • While their blood temperature isn't literally cold, the term "cold-blooded" refers to how the creature's body temperature is dependent on its environment. An animal that functions this way may also be called a poikilotherm. This relates directly to a reptile's metabolism, meaning their energy may be better expended in warm climates. This is why reptiles are usually found in greater abundance in countries closer to the earth's equator.

    Scales

    • The defining characteristic between reptiles and amphibians (both cold-blooded animals) is their skin surface. Reptiles have scales, very small plates covering their entire bodies. Scales prevent water from soaking into the reptile, enabling them to live in dry environments. The scales of lizards and snakes are epidermal, whereas turtles and crocodiles simply have dermal scales (scutes).

    Amniotic Eggs

    • Reptiles are sauropsids, meaning their eggs are laid with a hard outer shell. Embryos of the animal develop while in the egg. Like bird eggs, the animal emerges into the world not directly from its mother's womb (as is the case for most mammals), but from eggs that have been on land for a period of time. And once they hatch from their eggs, they need immediate food and air.

    Breathing Air

    • Though they share this characteristic with other types of animals, an important distinction of a reptile is its dependence on air. This sets them apart from amphibians, which live exclusively in water when they are first born. Reptiles can only breathe air, otherwise they will suffocate or drown.