Written by Niccoy Walker
Published: May 31, 2023
Image Credit © Bleijenberg


A reptile is cold-blooded and breathes air. It also has scales instead of feathers or hair.

Reptile Definition

Reptiles are vertebrate animals from the Reptilia class, either living or extinct. While reptiles can look very different from one another, they have some things in common. A reptile is cold-blooded and breathes air. It also has scales instead of feathers or hair. And most lay soft-shelled eggs on land. Reptiles have four limbs, except for snakes. However, snakes still descended from four-limbed ancestors.

The earliest reptiles originated over 300 million years ago during the Carboniferous period. They evolved from advanced tetrapods that had become adapted to living on dry land. The earliest true reptile is the Hylonomus, which lived 312 million years ago and was small and lizard-like.

A closeup of an alligator's head, its eyes closed in a sleepy expression.
Reptiles, like alligators, are cold-blooded animals that breathe air

© Derrick

Reptile Examples

The reptile comes in many different shapes and sizes. Here is a list of some of the most well-known reptiles.

  • Crocodiles
  • Alligators
  • Snakes
  • Tortoises
  • Turtles
  • Komodo dragons
  • Lizards
  • Dinosaurs

Reptile Characteristics

Reptiles share many of the same features, allowing them to stand out as their own class. They are cold-blooded (except for a few instances) and rely on external sources for heat. These animals have much lower food requirements than mammals. And they feature adaptive metabolisms, which allow them to thrive in many environments.

Compared to amphibians, birds, and mammals, reptiles are much less vocal. While some reptilian creatures possess the ability to vocalize, most species only make hissing noises.

And one of the most common characteristics of a reptile is its skin. It is covered in rough, horny epidermis, which allows it to be waterproof but also live on dry land. Reptile skin is fairly thin and covered in scales, sometimes forming armor. Turtle’s bodies are hidden inside hard shells consisting of fused scutes. Despite its rough appearance, reptile leather is not as strong as mammalian leather.

Reptile Diet

Reptiles are diverse creatures who also eat a varied diet. They can eat anything from insects and birds to leaves and grass. Reptiles can be carnivores, herbivores, or omnivores.

Check out this article for a comprehensive breakdown of reptile diets.

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About the Author

Niccoy is a professional writer and content creator focusing on nature, wildlife, food, and travel. She graduated Kappa Beta Delta from Florida State College with a business degree before realizing writing was her true passion. She lives in the Triangle area and enjoys hiking, reading, and cooking!