Skip to Content

Reptiles

Published:

Author:
Author Amy King, BSc Microbiology and Physiology

chameleon
Image by Nandhu Kumar via Pexels

Reptiles are fascinating creatures that have captivated many people’s attention due to their peculiar and often dragon-like appearances. Many reptiles have even made their way into our homes as beloved pets. 

We like reptiles, so follow along as we dive into their unique worlds, or skip ahead to any section! 

Introduction

Reptiles are widespread and can be found on every continent except Antarctica. There are approximately 12,000 living species worldwide; however, over 20% of those are threatened with extinction, according to the IUCN Red List. 

Reptile Characteristics 

First, reptiles include all animals in the class Reptilia, including lizards, turtles, snakes, and crocodiles. Next, reptiles have cold-blooded metabolisms, meaning they do not have internal body heat to keep them warm, like humans do, but instead rely on an outside source of heat, like the sun. Finally, most reptiles lay eggs, rather than give live birth like mammals. 

Smallest vs. Largest Living Reptiles

Scientific nameBody sizeHabitat rangeDietConservation status
Saltwater crocodileCrocodylus porosus2,200–3,300 lb (1,000–1,500 kg); 20 ft (6 m)Southeast Asia to northern AustraliaSmall to medium-sized mammals, reptiles, fish, birds, amphibiansLeast concern
Nano-chameleonBrookesia nana0.87–1.1 in (22–29 mm) Northern MadagascarMites, springtailsData deficient
saltwater crocodile
Saltwater crocodile.
Image by Maren Pauly via Unsplash
nano chameleon
Nano-chameleon.
Frank Glaw et al., CC BY 4.0, via Wikimedia Commons

Types of Reptiles

Snakes

Snakes are limbless reptiles of the suborder Serpentes. These creatures are often seen as dangerous, but they are misunderstood – with less than 7% being of any real threat to humans. 

If you’d like to find out more about the different kinds of snakes, as well as their symbolism throughout history, visit our dedicated snake page!

Lizards

Lizards include many scaly reptiles with limbs and moveable eyelids, such as iguanas, geckos, skinks, and chameleons, among others. Many species of lizards have impressive adaptations, like the Jesus Lizard that got its name from its ability to run on water. 

If you’d like to find out more about lizards and their cool characteristics, visit our dedicated lizard page!

Dinosaurs

Dinosaurs are an extinct clade of reptiles. For around 140 million years, they were the apex predators on Earth, until several cataclysmic events wiped them all out. Some modern-day animals evolved from dinosaur species, including birds and tuataras. 

If you’d like to find out more about the different types of dinosaurs, as well as their extinction, visit our dedicated dinosaur page!

Monitor Lizards

Monitor Lizards are an impressive reptile group belonging to the Varandiae family and have about 80 recognized species. They are all characterized by their powerful and long necks, claws, tails, and fully-developed limbs.

If you would like to learn more about the different monitor lizards, including the Komodo Dragon, visit our dedicated monitor lizard page!

Comparison of Five Different Reptiles

Scientific nameHabitat rangeDietUnique characteristics
SnakeSuborder SerpentesEverywhere except Antarctica and some islandsCarnivoresLimbless; many venomous 
LizardOrder SquamataEverywhere except AntarcticaMostly insectivoresFour limbs; long tails; rounded torsos
TurtleOrder TestudinesWorldwide continents, oceans, islandsOmnivores, some carnivores, others herbivoresWater-dwelling; thin, streamline shells
TortoiseFamily TestudinidaeEverywhere except Antarctica and AustralasiaHerbivoresLand-dwelling; round, dome shells
CrocodileFamily CrocodylidaeTropical Africa, Asia, Americas, AustraliaCarnivoresWater-dwelling; webbed feet; large streamlined bodies

Keeping Reptiles as Pets

beginner's guide pet lizards
Read more: Beginner’s Guide to Pet Lizards

Reptile FAQs

1. Do all reptiles lay eggs? 

Not all reptiles lay eggs. There are a few species, including Jackson’s chameleons and garter snakes, that carry their young in eggs that develop inside their bodies, but the eggs hatch inside the mother and the young are born “live.” This mode of reproduction is known as ovovivipary. 

2. How does cold-blooded metabolism work? 

Cold-blooded animals are known as ectotherms. Warm-blooded animals have warm body temperatures because when their body breaks down the food they have eaten for energy (metabolism), heat is produced. Cold-blooded animals lack the mechanism that releases heat during their metabolism, so they rely on environmental heat sources. 

3. Why do reptiles shed their skin? 

All animals shed their skin. Reptiles are unique in that they shed all their skin in one go, unlike mammals who constantly shed their skin in flakes. Depending on the reptile, shedding can happen several times a year. Shedding allows reptiles to outgrow their old skin, gets rid of any mites and bacteria that might live on the skin, and it throws off their scent from predators. 

4. How do reptiles breathe? 

All reptiles, even water-dwelling reptiles, breathe using their lungs in a similar way that mammals do. Amphibians and fish, in contrast, breathe using gills. 

Newest Category: Reptiles

Latest posts by Amy King, BSc Microbiology and Physiology (see all)

Posted on Last updated:

Unusual Fall Season For Almost All US States Predicted Spotting A Blue Jay May Be The Universe’s Way Of Telling You What You Need New York Rescue Duck Found Himself An Emotional Support Duck Spotting A Cougar May Be The Universe’s Way Of Telling You What You Need Do Bald Eagles Mate For Life?