Difference Between Mammals And Reptiles

Are you interested in learning more about the reptile species?

Do you ever wonder what sets your reptile apart from other household pets like dogs, cats, or guinea pigs?

If you are wondering what makes your pet a reptile and not a mammal, you might ask:

What is the difference between a mammal and a reptile?

Some of the most obvious differences between the two include mammals being warm-blooded as opposed to the cold-blooded reptile, the outer layer of skin, and their methods of reproduction. There are many other differences in addition to these top three.

Keep reading as we dive into the differences and similarities between these two classes of animals.

what is the difference between a mammal and a reptile

What Is The Difference Between A Mammal And A Reptile?

If you have ever wondered what makes a mammal a mammal and a reptile a reptile, you aren’t alone.

There are some critical differences between these two classes of animals, with some being more visible than others.

Scientists group different kinds of animals together based on their characteristics.

These groups are called classes.

Mammals and reptiles are just two of these classes, in addition to birds, amphibians, and fish.


The epidermis, or skin, is an apparent difference between these two classes of animals, and one you will be easy to identify on a glance.

All mammals have their outer layer of skin covered with hair, even if it isn’t very thick.

You, being a mammal, will notice hair all over your body, even if it isn’t as thick as the hair on top of your head.

Not all hair or fur is the same on mammals and doesn’t display itself as it does on you.

Some mammals have very different hair and present themselves in the form of long whiskers, defensive quills, and horns.

The hair on these animals is primarily used to insulate the body, keeping it warm when the environment is cold.

On the other hand, reptiles don’t have fur but instead are covered with a layer of scales.

But these aren’t the same scales you will find on a fish.

Fish scales are made of enamel and dentine, like your teeth, but reptile scales are made of protein.

Cold Blooded Vs. Warm Blooded

The cardiovascular systems in reptiles and mammals is another significant difference between these animals.

Reptiles are exothermic or cold-blooded animals.

This means they rely on the temperature around them to regulate their body temperature and perform regular bodily functions, like digestion.

Because they are cold-blooded and need warm exterior temperatures, you will only find them in the wild in warmer locales.

Mammals are warm-blooded animals and can generate their own body heat.

This means they can survive in places too cold to support reptiles. 


Another significant difference between the two classes of animals is how they reproduce.

Most reptiles will lay eggs, and the babies will hatch from those eggs.

There are some exceptions to this, and some reptiles might have live births, but this is not the norm.

All but a small handful of mammals, on the other hand, carry the growing fetus inside of them and give birth to a live baby.

Once the baby is born, it will stay with the mother for some time.

Female mammals have mammary glands and produce milk to feed their babies.

With reptiles, the females do not have these glands, do not produce milk, and most abandon the babies after they have hatched or sometimes after laying the eggs.

Other Differences

The three differences above are the most significant differences between mammals and reptiles, but there are others.

Teeth in mammals and reptiles also differ.

Mammals have specialized teeth throughout their mouth to tear and grind, but reptiles have uniform shaped teeth throughout their mouth.

The shape might be uniform, but the size can differ.

Also, reptiles are continually losing and replacing teeth throughout their lives, but mammals only will have two sets.

Mammals also have a larger and more complex brain than reptiles, giving them a higher cognitive ability level, meaning mammals are better able to reason, think logically, and have more memory.

The growth rate is another area where there is a difference between mammals and reptiles.

Once you reach adulthood, you stop growing.

Reptiles never stop growing all of their life.

Their growth rate will slow down significantly as they reach adulthood, but it won’t stop.

Are There Any Similarities Between Mammals And Reptiles?

After going over the many differences between mammals and reptiles, you might wonder what these animals could have in common.

Both mammals and reptiles are considered vertebrates, meaning they both have backbones.

Also, they both need and have several of the same organs in their body.

Lungs, found in both, are used for breathing, and even though it has a different number of chambers, both have a heart.

A brain and a nervous system are also found in both reptiles and mammals.

These are used to help the animals think, make decisions, and perform voluntary and involuntary actions daily.

Other organs, like eyes and ears, are found in both classes of animals.

The exception to this similarity is the snake, who does not have external ears.

Both of these multicellular organisms have been around on the planet for millions of years, evolving and growing.

The first appearance of reptiles and mammals dates back to the Carboniferous period, millions of years ago.

While most of the species the animals from back then are extinct, many have evolved and show up as you know them now.


Mammals and reptiles have many differences to distinguish between the two classes, but there are also similarities, showing we are all connected.

While we discussed some of the fundamental differences and similarities, more in-depth research would show you there are others out there.

We hope you now have a better understanding of what biological characteristics set your pet reptile apart from other household pets you or your friends might have.

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