Are Reptiles Mammals?

Even though they may have come from the same dinosaur ancestors, reptiles and mammals are totally different animals.
There are so many types of pets! As you learn more about your favorite cold-blooded buddies, you might start to wonder — are reptiles mammals? Or, are they their own group of animals? We're so glad you asked!

So, are reptiles mammals?

No, reptiles aren't mammals. They're a category of animals that includes lizards, snakes, alligators, and crocodiles. Our first records of these creatures date back 315 million years to fossils from the Paleozoic era.

Occasionally turtles are also lumped into the reptile labeling, but they are technically in their own class known as Chelonia. And, if you want to get real science-y, birds are sometimes added to the reptile category by researchers thanks to their genetic similarities to their scaly cousins and ability to lay eggs.

What are reptiles?

Reptiles are cold-blooded animals with backbones and breathe air. At a glance, you'll notice reptiles are covered in scales or bony plates (not hair or feathers) that shed regularly. Reptiles aren't able to maintain a constant body temperature internally — they rely on their environment (hot sun, a cool cave, a heat emitter, a log hideout) to help. Most reptiles lay eggs to produce young. A few varieties of snakes, worm lizards, and lizards have live births.

There are over 8,200 species of reptiles. Some of the most common ones you might be eyeing at your local pet store or reptile swap event include leopard geckos, ball pythons, bearded dragons, and corn snakes.

Fun fact: Most of us think of dinosaurs as reptiles. However, new research is discovering that many dinosaurs were actually warm-blooded and closer in structure to birds than reptiles!

What are mammals?

Mammals are warm-blooded. They also have backbones and breathe air. Unlike reptiles, mammals have skin or fur, not scales. These cozy body coverings and sweat glands (which reptiles don't have!) help them maintain a more constant body temperature.

When it comes to offspring, most mammals have live births. And the adult females have milk-producing mammary glands to feed their young.

There are approximately 5,400 species of mammals identified. You're probably familiar with lots of the common household mammal pets, including cats, dogs, guinea pigs, hamsters, and gerbils.

Fun fact: Some scientists hypothesize that mammals evolved from some classes of prehistoric reptiles.

So, now you know! Reptiles are not mammals. They are a class all their own. Learn more about your favorite lizards, geckos, snakes, tortoises, and turtles in these handy care sheets.