What’s the Difference Between Fur and Hair?

The Question: What’s the difference between fur and hair?

Submitted by: Lisa, New York, USA

The Short Answer: It depends on whether you want an answer based on scientific definitions, or an answer based on common usage. If you want the former, then the short answer is “nothing.” If you want the latter, then it really depends. It depends on what animal you’re talking about. For example, many people will say that hair keeps growing, whereas fur is something that grows to a certain length and then stops. So by that definition, your typical dog is covered with fur. However, if you’re talking about sheep, hairsheep are sheep that don’t need to be sheared because their fibers grow to a certain length and then stop. That would suggest that they should be called fursheep, not hairsheep.

People are covered with hair, not fur, right? But how about the hair on our arms and legs? It grows to a certain length and stops, which suggests it should be called fur. As should our eyelashes.

And when there are black fibers on your white sweater, it’s called cat hair or dog hair, not cat fur or dog fur.

More Information: Scientifically, hair and fur are made of exactly the same material, a protein called keratin. From a developmental standpoint, there is no distinction between the follicles from which hair, fur, eyelashes, whiskers, wool, or porcupine quills grow. They’re all hair follicles and it’s all hair.

If you want to know how the terms hair and fur are commonly used, you have to narrow the question to a specific animal. And even then, you’ll probably get several different answers. It seems to me that the most general distinction is that a dense coat of fine fibers is usually called fur. A less dense coat of thicker fibers like what you find on a human or a horse or a pig is usually called hair. And then, just to complicate things further, a very fine, very dense coat of fibers is often called wool, as with sheep, alpaca, and muskoxen. On the other hand, the animal with the finest, densest coat of all is probably the sea otter, but I’ve never heard their fur called otter wool – so go figure.

This quandary of whether to give a scientific answer or a common usage answer is a frequent one. For example, scientifically, the word “animal” refers to a large kingdom of living things that includes everything from sponges and corals to worms, insects, and mollusks, as well as vertebrates like fish and mammals. In common usage, however, many people use “animal” to refer only to vertebrates (fish, amphibians, reptiles, birds, and mammals), and some people restrict it even further to only the warm blooded vertebrates (mammals and birds).

Since this is meant to be a science site, I prefer the scientific answer, and to get back on track, I’ll state again that there is no biological distinction between hair and fur.

But what about this issue of whether it keeps growing or stops? Hair is “programmed” to grow for a certain length of time and then stop. Hair follicles typically go through a period of hair growth, then a pause, then the hair fiber falls out, and the follicle goes back into the growth phase and the cycle repeats. All of this is controlled by genes. So when people created dog breeds with short or long “fur” they were selecting animals with genes that programmed a longer or shorter period of growth. We humans also have a fair amount of variation in those genes. In fact, as I pointed out earlier, we have variation in the control of hair growth depending on where it is on our bodies. For most people, the hair on our heads has a much longer growth period that the hair on our arms or eyelids. But even the hair on our heads doesn’t grow forever, so I’m not sure the “grows and stops” versus “doesn’t stop” distinction is a valid one.

Just a little more: To confuse things a little more, other animals and even some plants are often described as having hair or being furry. Scientifically, only mammals have true hair and fur. Some plant stems and leaves may seem hairy, and some insects may seem furry, but it’s not the same kind of protein fiber as mammals have and doesn’t grow from hair follicles, so it doesn’t count – at least not technically. Of course, that doesn’t stop plants and insects from looking hairy or furry, so the common usage will undoubtedly continue.

Cite this article as: Pelletier, TC. (October 5, 2010). What’s the Difference Between Fur and Hair? Retrieved from http://askanaturalist.com/what%e2%80%99s-the-difference-between-fur-and-hair/ on July 3, 2020.

23 thoughts on “What’s the Difference Between Fur and Hair?”

  1. Wow! What an informative article. It just spurred quite an interesting conversation. Thanks!!! Next up – claws vs. nails

  2. I’m watching “Too Cute”. They said that Portuguese Water Dogs are excellent for dog lovers who suffer from allergies because they have HAIR instead of FUR… soooo this article didn’t really help.

  3. Not sure what you mean by “didn’t really help.” Are you suggesting that Too Cute is correct and my answer is not correct? As I said in my answer, there is little consistency in usage of hair versus fur. But as someone who is allergic to dogs, I can tell you that every dog I’ve ever been in contact with makes me react, no matter what kind of fiber covers them. However, some dogs, like the Irish Terrier who lives with me, and probably Portugese Water Dogs, as well, don’t shed much, and so my allergy is much more easily managed because the hair/fur isn’t everywhere. So if Too Cute wants to say that there is a difference between fur and hair, that’s fine. But they should say what they mean by that, because as far as I can tell, there is no accepted standard in common usage, and scientifically, there is no distinction at all between the two.

  4. That person wouldn’t be allergic to fur or hair, it would be an allergy to the animal’s saliva that is distributed into the fur through the animals cleaning themselves. Check the internet… full of information

  5. Right. That’s why it doesn’t matter what kind of hair/fur they have. All breeds release dander (dead skin cells) and saliva. But some breeds shed much more than others. So for some breeds, there is very little dander and saliva covered hair/fur around and for other breeds there is lots of it. People often say, as did the TV show Victiria referenced, that some dogs have hair instead of fur, and that makes the difference, but I think it’s just a matter of how many fibers they shed, whether you want to call them hair or fur.

  6. I thought fur grew more than one hair per folicle and hair usually only grew one hair per follicle…?

  7. Do you remember where you saw that? I did not come across that idea, but again, it depends on what kind of answer you want. Scientists don’t make a distinction between hair and fur. In common use, people make distinctions, but they’re not particularly consistent.

  8. Neither fur nor hair “stop” growing. All hair and fur grow to certain lengths and then fall out. The hair on our arms and legs grows on the order of inches before it falls out. The hair on our heads typically grows several feet before falling out. (We don’t notice this because most of us keep our hair trimmed.) Likewise, the reason the fur on some dogs is always the same length is because it uniformly falls out at that length. All the hairs (except those on my head 🙂 ) are routinely replaced by new hairs.

  9. Dj, It’s possible that some people use it that way, but I didn’t come across any information that suggests that is an official definition. Let me know if you come across a source for that.

  10. @ joel Williamson: hair does stop growing. It has a active growth phase of 2-6 years (anagen phase) then stops during a transition phase of a couple of weeks (catagen) then a dormant phase of up to 4 months (telogen) . During telogen, the follicle is preparing to grow a new hair. the hair finally gets pushed out (sheds) and the follicle re-cycles to anagen. 85% of your head hair is in anagen, and around 1% is falling out at any time. rest is dormant. Your max hair length depends on age and your own phase lengths.

  11. I found out that I am allergic to both cats and dogs and I have a very shedding boxer mix
    named Rambo after my favorite movie…I have asthma and my eyes itch and my voice gets raspy
    but love supercedes all illnesses…but my next dog will be one with no continuing falling hair…

  12. It’s been my experience with cats that the DSH ( domestic short hair) sheds less and their hair/fur is coarser while the DLH (domestic long hair) is silkier, and sheds more. Some dogs and cats lick themselves more then others.
    I find that the shorter coarser hair from some dog breeds ( akita, chuchua, daushounds) make me itch like crazy while (pits,bulldogs, pugs ) does not. THANK you for your answer. I thought hair was finer and fur was denser.

  13. Great article in explaining the difference between the scientific definition, usage and how different species of mamals shed hair/fur. We have a black lab. Is there any advice on how to deal with the hair it sheds everywhere?

  14. Since this article is of continued interest, in spite of its age, I am going to add a comment. While the article is technically correct, I also found it not to be useful. I found what I believe are more helpful answers on LiveScience, a “Livestock Production Management” page, and on the dogtime.com page for Portuguese Water dogs. Link urls will follow.

    Trying to keep my answer short, there are three types of hair: whiskers, outer coat (aka hair, guard hair), and underhair (aka wool, undercoat). The primary purpose of undercoat is insulation. The structures of the outer coat and undercoat are different. Fur is typically used to indicate the whole package (outer coat, undercoat) for non-human mammals, when it is soft and fine. When the hair is thick and bristly, it is not typically called fur – think of pigs and bristles.

    Wool sheep have been bred to only have an undercoat that continuously grows, although some do shed, and are thus called hair sheep. Portuguese Water dogs have been bred to only have an outer coat – a single layer of hair – and no undercoat. Which theoretically means they shed less.

    I have no data to support this, but it seems likely to me that dog breeds who are called hypoallergenic will only have a topcoat, with no undercoat. And that coat will probably have hair with thicker diameter than other breeds.

    As Tom has correctly pointed out, usage is not consistent. I notice that the “hair” sheep breeds I know of still only have an undercoat. Whereas for dogs the outer coat is less commonly referred to as hair, it obviously can be, based on the question asked here. And I have never heard of a dog’s undercoat being called wool. Hopefully I have added something that will aid others in finding the information they are looking for.


  15. I was trying to explain the fur vs. hair issue to some family members who are not native English-speakers. Your article was most helpful, thanks. My key example of just how idiomatic the usage of fur and hair are would be, posed somewhat in the form of a Jeopardy clue, “In a cat fight, the (blank) is flying.”
    I’ll take keratin for $2,000, Alex.
    Nice work.

  16. for people who work with animal fibers, there is a difference in hair and wool, for example many llamas have (guard)hairs that shed rain, dogs do too, these are coarse and usually straight where as the wool underneath is finer and most importantly has crimp. Some sheep wools have a lot of fine crimp like Merinos while others have a lot less crimp, and are more like wavy as in Coopworths. And there are all sorts of variations in between. While hair and wool both come from follicles, there are differences……

  17. I have a Yellow Lab and a Porty. The Yellow sheds but is very easy to groom/brush and wash. Our Porty has continuous growing hair, so we have to clip him regularly, but some of the hair grows very very close to his lips and eyes. If we dont trim this every week, it gets uncomfortable for him. His mouth is always wet and slimy, and he wipes it all over our clothing, especially after a meal or water dish. And Ive seen dogs in dire need of being trimmed, and the hair covers their eyes like a towel.
    So I guess my question, is:
    Why are some dogs encumbered with this anomaly, was it naturally occurring, or was it a result of breeding? As I wouldn’t think that if a hair dog was in the wild, whether the hair would grow so long, that the dog couldn’t survive.

  18. I am not aware of any wild canids that have continuously growing hair as a species. That doesn’t mean that there isn’t one occasionally born that way due to a genetic change. If the trait is neutral or advantageous to survival and breeding, it might continue or even eventually become universal in the species. If there is even a slight disadvantage to the trait, it is likely to die out over time.

    With continuously growing hair, we could imagine that it might get excessively tangled and matted, leading to all kinds of problems. Dog breeders, however, presumably found the Portugese water dog’s hair interesting and people made up for any disadvantage by trimming their hair and selectively breeding them until they trait was “fixed” in the breed. Tom

  19. Thank you! Ive always wondered about this.
    Ive always thought that dogs are the subjects of forced evolution by breeders using selective breeding and genetic engineering/manipulation. I can see the usefulness for cattle, to produce more meat and milk, and plants to produce better food or more flowers.
    I wonder where in the evolution of domestic dogs was this hair anomaly started? And what the purpose was? I know that certain dog breeds have very difficult ‘traits’ as the flat noses and problematic breathing for example.
    But this hair must have been done for looks, not for any useful purpose. Looking at how show dogs, Poodles for example, are given hilarious hairdos, is something Ive not really been fond of. I have always preferred our Labs, and Lab mixes, for the sweet dispositions of this type of dog. Very interesting, Ive spent the morning Googling for the actual beginning of the ‘hair’ gene.

  20. Thank you again, Im sending this article to some family members, as if you do elect to get a ‘hair dog’, you will have to pay to have their hair cut, or do it yourself. We groom our own Porty, but its not really an easy task. And I brush our Yellow Lab daily during shedding season, which seems to be all year round for her.
    If we let our Porty go a bit too long between haircuts, his head and mouth gets very uncomfortable and the hair covers his eyes. So we do his head once a week, and paws too so his fur doesnt mat.

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