Mammals vs Reptiles: Difference and Comparison

Mammals and reptiles are two of the five classes of vertebrates. There are more than 5,000 species of mammals, including bears, whales, wolves, apes, bats, and even humans.

Reptiles are a more diverse group than mammals, with more than 8,000 species, including lizards, crocodiles, snakes, turtles, and so on.

Key Takeaways

1. Mammals are warm-blooded animals that give birth to live young, while reptiles are cold-blooded animals that lay eggs.
2. Mammals have hair or fur, while reptiles have scaly skin.
3. Mammals have a diaphragm to help them breathe, while reptiles do not.

Mammals vs Reptiles

Mammals are vertebrates that are warm-blooded animals covered in hair. They feed their young with milk from mammary glands. Female mammals give birth to their young ones. Reptiles belong to the class Reptilia which are cold-blooded creatures with rough, scaly skin. Female reptiles lay eggs covered with calcareous shells and abandon their offspring once the egg hatches.

Mammals are one of the five classes of the vertebrate group. Mammals are warm-blooded animals and have mammary glands from which milk is secreted to feed their offspring.

They have bodies covered by hair. Hairs in the body help mammals to survive cold climates. However, whales don’t have hair in their bodies.

Reptiles are another type of animal class of the vertebrate group. Reptiles are cold-blooded animals and depend on their surroundings to warm up their body.

Reptiles have dry skin which is covered either with horny plates or scales. They breathe by using their lungs. Most of the reptiles lay eggs on the ground and eat other animals for survival. 

Comparison Table

Parameters of Comparison	Mammals	Reptiles
Skin	Mammals have hair all over their body. They also have sweat glands on their skins.	Reptiles don’t have hair on their body. Rather, they have scales, which are quite different from fish scales, that arise in the epidermis (upper layer of the skin) instead of in the dermis layer of the skin.
Teeth	Mammals have specialized teeth, like morals which are used for grinding food, and canines which are used for tearing through the meat. They grow only two sets of teeth throughout their lives.	Reptiles have uniform shaped teeth, though it varies in size. Reptiles continuously grow teeth throughout their lives.
Jaw and ear bones	Mammals have a lower jaw bone firmly attached to the skull. The lower jaw bone is one continuous bone. Biologists believe that the lower jawbones of the reptilian jaw have evolved into the three middle ear bones of mammals.	The lower jaw of the reptiles has multiple bones. But they have only one ear bone.
Cardiovascular system	The mammals’ heart has four chambers- two atria and two ventricles. Ventricles deliver oxygenated blood to the body organs and atria direct blood to the lungs to re-oxygenate the body. As a result, the mammalian body always remains warm.	The reptilian heart consists of three chambers- one atrium and two ventricles. Unlike mammals, reptiles are cold-blooded. They need to depend on the environment to warm their body.
Reproduction	All-female mammals give birth to live young. They have mammary glands that secrete milk to feed their offspring.	Most of the reptiles lay eggs. Female reptiles don’t have mammary glands. They abandon their young after hatching.

What is Mammals?

Mammals are one of the five classes of vertebrate animals. Mammals give birth to live young and feed their young with the milk secreted from their mammary glands.

Besides these characteristics, mammals are distinguished from other classes by some other characteristics. They have hair covered all over their body.

However, whales don’t have hairs on their body. They also have sweat glands on their skins.

Mammals have a lower jaw bone firmly attached to the skull. The lower jaw bone is one continuous bone. Biologists believe that the lower jawbones of the reptilian jaw have evolved into the three middle ear bones of mammals.

Mammals have specialized teeth, like morals, which are used for grinding food, and canines, which are used for tearing through the meat. They grow only two sets of teeth throughout their lives.

The mammals’ heart has four chambers- two atria and two ventricles. Ventricles deliver oxygenated blood to the body’s organs, and atria direct blood to the lungs to re-oxygenate the body. As a result, the mammalian body always remains warm.

The Mammalia class has produced a diverse habitat and form. The Mammalia class is distributed worldwide. There are over 5500 species of mammals arranged in almost 125 families.

The most numerous in existing mammals are rodents. It is accepted that mammals are the most adaptable compared to any other animal class (insects and arachnids are exceptions).

What is Reptiles?

Reptiles are another class of vertebrate group that have amniotic development, epidermal scales covering all over their body, and internal fertilization.

The major living reptile groups- the tuatara, the turtles, snakes, crocodiles, and lizards- account for more than 8700 species.

Reptiles have uniform-shaped teeth, though they vary in size. Reptiles continuously grow teeth throughout their lives. The lower jaw of the reptiles has multiple bones.

But they have only one ear bone. The reptilian heart consists of three chambers- one atrium and two ventricles. Unlike mammals, reptiles are cold-blooded. They need to depend on the environment to warm their body.

Most of the reptiles lay eggs. Female reptiles don’t have mammary glands. They abandon their young after hatching. Reptiles don’t have hair on their body.

Rather, they have scales, which are quite different from fish scales, that arise in the epidermis (upper layer of the skin) instead of in the dermis layer of the skin.

Reptiles lay eggs that are covered with leathery or calcareous shells. They feed their offspring through hunting. Some of the reptiles abandon their offspring after hatching.

Some of the reptiles use their tails as a defence mechanism. Snakes use venoms to the enemy as a defence mechanism.

Main Differences Between Mammals and Reptiles

1. Mammals have hair all over their body. They also have sweat glands on their skins. On the other hand, reptiles don’t have hair on their body. Rather, they have scales, which are quite different from fish scales, which arise in the epidermis (upper layer of the skin) instead of in the dermis layer of the skin.
2. Mammals have specialized teeth, like morals, which are used for grinding food, and canines, which are used for tearing through the meat. They grow only two sets of teeth throughout their lives. Reptiles have uniform-shaped teeth, though they vary in size. Reptiles continuously grow teeth throughout their lives.
3. Mammals have a lower jaw bone firmly attached to the skull. The lower jaw bone is one continuous bone. Biologists believe that the lower jawbones of the reptilian jaw have evolved into the three middle ear bones of mammals. The lower jaw of the reptiles has multiple bones. But they have only one ear bone.
4. The mammals’ heart has four chambers- two atria and two ventricles. Ventricles deliver oxygenated blood to the body’s organs, and atria direct blood to the lungs to re-oxygenate the body. As a result, the mammalian body always remains warm. On the contrary, the reptilian heart consists of three chambers- one atrium and two ventricles. Unlike mammals, reptiles are cold-blooded. They need to depend on the environment to warm their body.
5. All female mammals give birth to live young. They have mammary glands that secrete milk to feed their offspring. Most of the reptiles lay eggs. Female reptiles don’t have mammary glands. They abandon their young after hatching.

References

1. https://www.cabdirect.org/?target=%2fcabdirect%2fabstract%2f19762274394

Last Updated : 25 August, 2023