Do cats have hair or fur? It may seem like semantic, and possibly pedantic, distinction. But it makes you curious. Is there a difference between hair and fur? If so, why do we say cat hair and not cat fur?
Many times when I have used the word fur to refer to a cat’s coat, I have been corrected, and told that “cats have hair, not fur.” When I asked what the difference was, it was never explained. The idea of a cat having a “coat of fur,” itself, is good geeky humor and has to do with the etymology of the word fur. You may want to skip to the bottom and read about the origin of the word fur, which may surprise you.
There is a reason for this question about hair versus fure. There is an ongoing debate about several domesticated animals. Does the cat have hair or fur? Does a dog have hair or fur? Does a guinea pig have hair of fur? When we ask the difference we get either no answer or an answer that seems quite inadequate.
This is because, scientifically, there is no difference between hair and fur. They are both made of keratin. Even your fingernails and skin are made of the same stuff. And a bird’s feathers, too.
Is Shorter Cat Hair Fur?
Sometimes, fur is considered to be hair that grows to a uniform short length. This explanation does not work very well.
You will notice that the hair on different parts of your body has different textures and strengths. It also grows to different lengths. The hair on your arms, for example, grows to a uniform short length and stops. The hair on your head will grow to a much longer length. Dp you have fur on your arms and hair on your head?
Many people mistakenly believe that the hair on their heads, if left uncut, will continue to grow and grow. This is not true. Just like the hair on other parts of your body, your hair will only grow to a certain length, and then stop. When you see women who have been able to grow their hair down to the middle of their legs, this is actually a variation on the norm and it is rare. Just as there are people who can grow their hair extremely long, there are some people whose hair never grows more than a few inches in length. So, most of the time, all hair grows to a certain length and then stops.
Some mammals have long hair, and some have short. Some have mixtures of both. Most humans would not accept the idea that they have fur, even though they have short hairs on parts of their body.
Thicker Or Thinner Hair
In the animal kingdom, one practice is to refer to animals which have hairs with thicker shafts as possessing hair, and those with thinner shafts as possessing fur. Since, through selective breeding we sometimes change the way an animal’s hair grows, we end up with animals with thicker and longer strands of ‘hair.’ This happens to dogs, for example. With cats the same holds true so the difference is purely semantic.
Despite differences in texture, to say that a strand of fur is much different than a strand of hair is simply incorrect.
How Many Hairs Do Cats Have? Follicle Density of Cats
When we say “thick hair” we are not always clear about what we mean. Do we mean the thickness of an individual strand of hair? Or, do we mean the relative abundance of hair shafts within a certain area. Some animals have a higher follicle density than others. This means that for any given unit of skin there are more or less hair follicles. We can only try to come up with averages, but cats can have up to 200 hairs per square millimeter and those hairs will be different types of hair (more on this below). We humans can have 200 to 400 hair follicles per square centimeter (not millimeter) on our heads. Cats do, then, on average, possess thicker hair.
Does follicle density explain the difference between hair and fur? For example, are apes furry? Apes actually have a follicle density similar to our own and our scalps have around the same follicle density as some other “furry” creatures. Unless we are ready to start calling our head hair “fur,” follicle density just doesn’t make a good distinction.
Topcoats and Undercoats
However, there is another distinction that may help to separate a coat of fur from a hairy body. The hair on our bodies and heads is what is called primary hair, which is opposed to secondary hair. Primary hair is longer and courser than secondary hair. In animals, this is also called guard hair or a top coat.
Secondary hair, also called ground hair or down is hair that is shorter and fluffier and makes up the undercoats of many mammals. Now, notice that ground hair and guard hair are both still hair. But, when the two appear together, it is called fur. Your cat, then, has fur. His hair is much thicker, and much fluffier than the hair on your head. He has much much more of it.
The Primary hair and the undercoat function together as defense and protection. The primary hair keeps out insects, twigs, and other irritants. The secondary hair repels water and helps regulate body temperature.
Polar bears are a great example. Their undercoats, or layer of secondary hair, is second to none and is very important in protecting them from the temperatures of the frozen north.
Cat Fur: Ground, Awn, and Guard Hairs
Cats usually have three types of hair in their coats, ground, awn, and guard. The ground coat, or undercoat is soft, fluffy, and curly. The awn hairs are course and bristly. The guard hairs are longer. Together, the awns and guard hairs make up the top coat. Different breeds of domestic cat can have slightly different proportions and variations on different parts of the body. And some may be missing one hair type.
Sometimes, in certain breeds, changes in the length or texture of one type of hair causes people to think that this cat is missing this type of hair. For example, the Turkish Angora is often said to possess no undercoat. In reality, the ground hairs are simply very long and fine, and less profuse than some other cats. The Russian Blue has awn and guard hairs that are the same length, so they are called, confusingly, double-coated.
If you’ve ever brushed your cat you’ll notices all the fluffy hair coming out into the brush. This is the ground hair or down. With so many different names, you can see why it’s hard to get straight answers.
Humans Compared to Cats and Other Animals
Humans obviously do not have what could be called a coat of fur. There are other mammals that also do not have fur. Other primates, for example, only have hair, just more of it. As well, horses have hair. Have you noticed that horses can grow long head hair? Orangutans can as well.
And some domestic dog breeds have also lost, or undergone changes, in their undercoats. As you can see, when all the myriad variations are taken into account, the distinction between fur and hair becomes even less sensible.
Beyond all these distinctions, which even a scientist would agree can become useless if overindulged, it really does not matter. As you can see, there is no one universally accepted definition for fur. Biologist are usually happy with using the word hair for all of it. That’s right, even biologists think the distinction is semantic.
How did this fur versus hair thing get started in the first place?
Origin of the Word Fur
The origin of the word fur may prove enlightening. Surprisingly, there was a time when we did not refer to an animal as having fur and walking around with it! That is, a fur was not a fur until it had been removed from an animals body and used by a human to keep warm. Even before this, fur was a verb. So, in the Middle Ages, an animal’s pelt was used to line the garments of the wealthy and these garments were referred to as being furred with parts of the pelt. The Middle English word furren came from the Middle French word fourrer, which meant “to line a garment.” The word developed into a noun, so that the pelts themselves, or the trimming from them, were called furs.
As the word evolved, an animal that might be useful in the way of furs for humans, especially ones that had thick but soft coverings of hair, were said to have furs or to be furry. Notice as well that we refer to animals as having a “coat of fur,” a “topcoat” and and “undercoat.” This too, is a leftover from the fur coat for humans. We sometimes joke, in my house, about our cats taking off their fur coats to be dry cleaned.
Clearly, this was not a scientific designation! It was handed down to us and we have simply attached some scientific distinctions to the word after the fact.
When it comes to your cat, you can say he has hair or he has fur, and either way, you probably aren’t going to make a nice soft pair of gloves from him.