The main difference between mammals and reptiles is that mammals are born alive and produce milk for their young, while reptiles lay eggs.

Mammals vs. reptiles

Mammals are warm-blooded animals, while reptiles are cold-blooded animals. Mammals give birth to live young; on the other hand, reptiles are animals that lay eggs. Mammals have fur-like hairs on their bodies, while reptiles have a hard, scaly body.

The mammalian heart contains four chambers: right atrium, left atrium, right ventricle, and left ventricle; on the contrary, the heart of reptiles contains three chambers; right atrium, left atrium and ventricle. Mammals have a diaphragm for breathing, while reptiles do not have a diaphragm.

Mammalian bodies have high metabolic rates; on the other hand, reptiles have low metabolic rates. Mammals are viviparous animals, while reptiles are oviparous. Mammals have mammary glands for milk production; conversely, reptiles do not have mammary glands.

Mammals have limited growth after adulthood, while reptiles are in continuous growth. The mammalian brain is larger than that of reptiles; on the other hand, they have a small brain. Mammals have three middle ear bones: the hammer, anvil, and stapes, while reptiles have only one bony middle ear columella.

In mammals, teeth appear twice during their life: deciduous and permanent teeth; in contrast, in reptiles, teeth are continually replaced by simple cheek teeth. Mammals have fused pelvic bones; on the other hand, in reptiles, the pelvic bones are separated.

In mammals, growth is limited after adulthood, while in reptiles, growth continues throughout life. The pelvic bones of mammals are fused, while the pelvic bones of reptiles are separate.

What are mammals?

Mammals are the type of animals that is categorized by the existence of mammary glands that exist in females that produce or produce milk for their young. Mammals belong to the class Mammalia. The word mammals originate from (Latin word mamma), which means “breast.” Dogs, whales, horses, and elephants are also examples of mammals. Humans are mammals too.

Main characters of mammals

• Mammals have a special type of part of the brain, which is called the neocortex.
• They have fur or hair all over their bodies.
• Mammals have three middle ears. (missing word bones)
• They have a four-chambered heart.
• The single-bone jaw is present in mammals.
• The mammary glands are present for the production of milk.

What are reptiles?

Reptilian animals are also known as egg-laying animals. They crawl on its belly or on its short legs. They are also known as cold-blooded animals. The reptile’s name originated from the French word (Reptilis), which means creeping. It belongs to the class «Reptilia». Examples of reptiles are snakes, turtles, lizards, crocodiles, tuátaras, etc.

• They are cold-blooded animals. Reptiles are ectothermic; therefore they cannot control their own body temperature.
• They are tetrapod animals.
• They have a hard and scaly body.
• All reptiles produce eggs, most reptiles lay hard-shelled eggs, but some give birth to live.
• Breathe through lungs.
• Most reptiles reproduce sexually, but some reproduce asexually.

Key differences

1. Mammals are warm-blooded. This helps mammals live in a variety of different temperatures. Some mammals live in freezing temperatures while others live in very high temperatures. Reptiles are cold blooded. They can regulate their own body temperature.
2. Mammals are endothermic and internally regulate their body temperature, but reptiles are ectothermic because they depend on the environment to do it for them.
3. Mammals can produce body heat, while reptiles need an external heat source such as the sun.
4. Mammals have skin that is normally covered with hair, while reptiles have scaly skin (the skin has a large number of plate-like structures).
5. Mammals have sebaceous and sweat glands in the body; on the other hand, most reptiles do not have sebaceous or sweat glands.
6. Mammals give birth to young and feed them their own milk (only females do), while reptiles do not give birth to their young instead of laying eggs. (Except for some like yellow anacondas, but they are still reptiles because the egg hatches in their stomach).
7. Mammals remain the same color, while reptiles can change color depending on their mood and environment.
8. Mammals keep their young after birth and raise them. Reptiles leave their young once they give birth.
9. The placenta develops in mammals, whereas the placenta does not develop in reptiles.
10. The skull of a mammal meets an expanded skull, while reptiles have a small skull.
11. Mammals have high levels of cognitive ability; on the other hand, reptiles have low levels of cognitive ability.
12. The mammalian jaw is made up of a single bone; on the contrary, the reptilian jaw is made up of several bones.
13. All mammals with four-chambered hearts, while most reptiles with three-chambered hearts
14. In mammals, the bony plate separates the mouth and the nasal passage; on the other hand, the bone plate is incomplete in reptiles.
15. Mammals are involved in the ribs that taper to the thoracic vertebrae, whereas the ribs of reptiles are found in the entire vertebrae.
16. In mammals, the limbs lie directly below the body, while in reptiles the limbs emerge horizontally from the body.
17. Mammals have a high metabolic rate; on the other hand, reptiles have a low metabolic rate.

Mammals give birth to live young and have mammary glands to feed their babies. Reptiles suckle or feed their young by hunting or stalking food. The body of mammals is covered in hair, while the body of reptiles is covered in scales. The main difference between mammals and reptiles is the mode of reproduction.