Why Are Cats Mammals?

Cats are the only domesticated species of the Felidae family. Cats were domesticated by the Ancient Egyptians approximately 4,000 years ago, and have been kept as pets ever since.

Somebody asked me recently if cats were mammals, and this made me wonder if they have all the mammalian characteristics.  

Cats are mammals and have seven mammalian traits. Cats are vertebrates, they have mammary glands which they use to feed their live young, have a four-chambered heart, have hair, have sweat glands to cool down, possess a large neocortex, and have three inner ear bones.

If you want to find out more about the characteristics that cats share with other mammals then please read on.


Is A Cat A Vertebrate?

One of the characteristics that all mammals have is that they have a backbone inside their body. However, it is not just mammals that have a backbone. Other animals such as fish, amphibians, reptiles, and birds also have a backbone. Animals with a backbone are called vertebrates.

There is another group of animals called invertebrates. These are animals that don’t have a backbone inside their body. Some examples of these include single-celled organisms, earthworms, starfish, octopus, snails, clams, insects, and spiders.

Cats are classed as vertebrates as they do have a backbone inside their bodies. The spinal cord is surrounded by cartilage or bone.

Does A Cat Have Mammary Glands?

Another characteristic that mammals have is mammary glands. The name mammal is taken from the Latin word mamma, which means breast and was popularised by Carl Linnaeus, a Swedish botanist, and zoologist.

Mammary glands are used to produce milk to feed the young after birth. Milk is produced in the mammary gland after childbirth and is called lactation.  

Cats produce milk within their mammary glands. Cats have eight mammary glands which are arranged in four pairs on the left and right underside of the body. Cats produce milk to feed their kittens after birth.

Kittens are usually fully weaned off milk from their mother between eight to ten weeks, although this can be as early as four weeks. The milk contains essential nutrients for cats in the early stages for them to grow healthy.  


Does A Cat Have A Four Chambered Heart?

Mammals all share another characteristic, one which is also shared with birds. Both birds and mammals have a heart that contains four chambers. Surprisingly, crocodiles, which are a reptile, also have a four-chambered heart.

The four-chambered heart is essential for the respiratory system of mammals. When mammals breathe in air, they take in oxygen. Oxygen is needed to survive but the waste product once the oxygen has performed its function is carbon dioxide. Carbon dioxide is expelled back into the air when we breathe out.

The respiratory system allows us to breathe in oxygen and breathe out carbon dioxide. Oxygen enters the lungs where the cells of the body transport it through the blood to the left ventricle of the heart. The left ventricle pumps oxygen-rich blood to the left atrium. It is then pumped through your arteries to the rest of your body. 

The other two chambers of the heart are the right atria and right ventricle. Oxygen-poor blood is received from the veins and is pumped to the lungs where the carbon dioxide is expelled.

The four-chambered heart which mammals possess is essential. A four-chambered heart is essential for warm-blooded animals as they expend a lot of energy and require a lot of oxygen. The four-chambered heart is an efficient way of getting lots of oxygen into the body.


Cats do have a four-chambered heart. Cats need plenty of oxygen as it is needed to burn sugars and fatty acids in their cells to produce energy. The energy is needed for everything they do including keeping themselves at a steady temperature.

Do Cats Have Hair?

Another characteristic of a mammal is that they have hair or fur. The fur is generally used when a mammal has very thick body hair. Humans have hair, but we wouldn’t generally call it fur, whereas other mammals which are covered, such as bears or raccoons would have fur.

Hair or fur consists of two layers. These consist of a thicker underfur covered with oily guard hairs on top.  

The guard hairs are longer and coarser. They are used to repel water from the skin and to block ultraviolet rays from the sun. In animals that have markings, such as a jaguar, these markings are on the guard hair layer.

The thick underfur, or down fur, is used to keep the animal warm and is made up of curly or wavy hairs.

Even whales and dolphins have hair, although some species only have hair follicles. Species such as the humpback whale have hair their entire life with a single hair coming out of each hair follicle.  

Toothed whales usually lose their hair shortly after birth.

As anyone who has seen a cat will know, they do have a coat of fur. The hair on a cat is also known as fur and come in many different lengths, shape, and colors. The color and pigmentation come from the guard hairs.  

Cats such as the Persian cat and the Siberian cat have long hair, while the American shorthair cat and the Bombay cat have shorter hair.

However, not all cats have fur. The Sphynx cat does not have a coat, although they may have fine hairs. Some are completely hairless.


Do Cats Have Sweat Glands?

Mammals need to regulate their temperatures, and although all mammals sweat, you may not have seen your cat or dog sweat the way we do after we have been for a run.  

For us, sweating is a way of regulating our body temperature so that we don’t overheat. The sweat glands produce sweat which is then carried away from the body by evaporation. This carries away the heat and makes us feel cooler.  

Humans aren’t the only mammals that sweat through their skin. Primates and horses also sweat through sweat glands.

Some other animals use different ways to expel heat from their bodies. These can include panting, which is something you see in dogs when they have been out playing. This allows them to get rid of heat through their mouth

Most mammals do not have sweat glands on their bodies in the same way we do and need to use these other ways to cool down.

Cats are one of the strangest mammals in regards to sweating as they do sweat, but not in the way that we do. Cats do have sweat glands on their bodies, but as their fur covers most of them, they do not provide an adequate way to cool down. 

Cats have the most sweat glands on their paws and sweat using these. On a hot day, you may notice that your cat is leaving wet pawprints on the ground, and this can also happen if they are stressed, such as before or after a trip to the vets.  

As we can see, cats have all of these mammalian traits and are most definitely classed as mammals.

Do Cats Have A Neocortex?

The brain is one of the most complex organs in a mammals body.

The cerebral cortex is the outer layer of the brain and is used for functions such as movement, processing information from the five senses, decision making, and in humans, speech. 

The neocortex is a set of layers of the cerebral cortex and it is this part of the brain that controls sensory perception, motor commands, spatial reasoning, and conscious thought.

The neocortex also allows mammals to store memories, including experiences and events.  

The larger the neocortex, the larger the capacity to control conscious thought, spatial reasoning, motor commands, and sensory perception.

The majority of brain cells are found in the neocortex and the cerebellum. The cerebellum is used for posture, coordination, and balance.

The neocortex looks different in different animals. Humans, primates, and other larger animals have grooves (sulci) and ridges (gyri) and the brain is similar to what you may have seen before. The grooves, ridges, and folds allow a much larger neocortex to fit inside a smaller space.

Small mammals such as rodents do not have the deep grooves and ridges and the neocortex is much smoother. This shows that their brains are much smaller in comparison.

Cats do have a neocortex but there are fewer folds and therefore a smaller neocortex relative to their brain size. However, a cat’s brain is 90 percent similar to humans.

A cat’s brain measures about two inches and weigh between 0.9 to 1.1 ounces.  

However, cats are intelligent, as anyone who has had a cat will know. Cats are one of the smartest mammals, although most studies done on the intelligence of pets are done about dogs.  

Cats have 300 million nerve cells compared to 160 million in dogs, and a staggering 26 billion nerve cells in humans.  

Cats use their intelligence in different ways. They learn from what they have done before and the outcomes of this and also learn by observation. Cats will remember positive experiences and bad, such as a trip to the vets.

Do Cats Have Three Middle Ear Bones?

Another trait that mammals possess is three bones in the middle ear. These three small bones are called ossicles and conduct vibrations (sound) to the inner ear from the eardrum.

The three bones are called the malleus (hammer), the incus (anvil), and the stapes (stirrup).

Once the vibrations are in the inner ear, the vibrations are converted into nerve impulses. These three bones play a vital role in a mammal’s ability to hear.

With many animals relying on their sense of hearing to be able to hear prey and predators, this evolutionary trait is essential for mammals to survive.

Cats do have the three small inner ear bones which help them to hear. Cats can hear the same range as a human, and much more. Cats can hear the same low frequencies that we can, but their hearing at higher frequencies is much better. Cats can hear frequencies up to 64kHz and can hear frequencies higher than a dog.

Cats have large ears which help them to hear better than a lot of other animals.

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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