The werewolves in my setting have a problem. Letting humanity at large know that either they or any other sort of magical creature actually exists is illegal, and so they have to pretend to be human. For the most part, this is pretty easy for them to manage. They can control their transformations basically at will (the only limitations are on when they can use their wolf form, not their human form), and aside from being naturally more fit than the average human, they look identical to one.

...With one exception.

A werewolf's androgenic hair (that being beard and body hair) has far more in common with the fur of a wolf than the body hair of a human. It grows in the same places, and at the same speed, as on a human, but it's definitely not human hair. So in order to pass as a human, werewolves can't have beards (or any other body hair a human is likely to see), and need to shave regularly before it gets too long.

The question I have is... how long?

If someone were trying to conceal the fact that their beard and body hair is actually wolf fur, how long could it get before it became clear, whether by sight or touch, that this stubble isn't natural?

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    $\begingroup$ Does it grow everywhere: eyelids, nose, between fingers etc.? $\endgroup$ Commented Apr 22, 2022 at 10:58
  • $\begingroup$ @EveninginGethsemane No, same places it grows on a human, and at the same speed. I'll add that to clarify. $\endgroup$ Commented Apr 22, 2022 at 11:00
  • $\begingroup$ I suspect the thing that would actually stand out to most people is that all the werewolves have the same LENGTH of hair, not the unusual texture of the hair. ("It's weird, Angela, your hair is always short, but not buzzed, and you've never been to a hairdresser in the three years we've been dating!") $\endgroup$
    – Jedediah
    Commented Apr 22, 2022 at 13:17
  • $\begingroup$ @Jedediah Head hair is unchanged and normal. $\endgroup$ Commented Apr 22, 2022 at 13:20
  • $\begingroup$ why is it "definitely" not human hair the only difference canine hair from human hair at the individual hair level is canine hair has multiple follicles and it grows a lot slower. $\endgroup$
    – John
    Commented Apr 29, 2022 at 0:27

6 Answers 6


To properly answer this question, we must consider the nature of both human sexual hair, i.e. pubic, armpit and beard hair, and canid body hair.

Any of us who have a dog - or cat - should be familiar with canid body hair. It is typically around an inch long, give or take, depending on breed, and 75 to 200 microns thick. Canid fur is typically round or nearly round in cross-section. Studies have been made in great depth on the nature of dog hair.

Human sexual hair is quite different to both human head hair and canid body hair. Human head hair varies from 17 to 180 microns, averaging about 70 microns. It is typically round or oval in cross-section. Beard hair is around twice this thickness, and is highly elliptical or even triangular or trapezoidal in cross-section, around 150 to 200 microns thick.

So, beard hair may be around as thick as dog hair, or even thicker, but it also has a significantly different growth pattern. Because of its cross-section, human beard hair is curly, while dog hair lies flat and straight. Beard hair also has irregular reflective properties, while dog hair reflects light more consistently.

The question asks how long can a dog hair beard be before another person can tell that it isn't a human beard. Unfortunately, that isn't a simple question despite the obvious differences, depending on the visual acuity of the observer, how closely they observe the subject, and how familiar they are with beards. The latter is more a cultural factor.

We can be pretty certain that short (< 1mm) dog hair stubble would be almost indistinguishable from beard hair. The hair could probably get to 2-3mm long before the differences in growth pattern and appearance would begin to become obvious. Observers who don't get too close or who aren't familiar with beards might miss the differences at 5-6mm long. We can be pretty certain that a dog hair 'beard' 10+mm long would be obvious to all but the most unobservant humans with normal vision.

However this doesn't account for the feel of a beard vs dog hair. At much over 1-2mm, dog hair would feel much softer than a beard, due to the lower stiffness of dog hair in comparison to beard hair. However, a person with dog hair in place of beard hair would be better able to prevent accidental contact with it than to prevent people from seeing it.


Right Idea Wrong Question?

I don't think the length of the hair/fur matters so much as where it grows and how much. Hair and fur are the same thing. What differentiates people and cats or dogs is roughly how much each grows and how thick it is. Most mammals grow very thick hair: think about a cat or a dog's coat. Generally they uncovered skin you can see are the paw pads, the lips, the tip of the nose and sometimes right at the tip of the tail.

There are of course different qualities of hair, some softer and some coarser, and some kinds grow long while others grow short. Think "short haired cat" vs "long haired cat".

If your Werewolves have body hair that grows in the same places as humans and in the same way, then they shouldn't have any problem at all. As described, they would be visually indistinguishable from humans. Even if they also grew some softer fur, another person would be unlikely to notice except upon close inspection.

Werewolves would only face recognition problems if their hair grew in a lupine pattern --- hair covering the entire body, including the face & extremities. Or, if in a human pattern, then in a lupine colour scheme --- mixtures of various colours of hair rather than the normal human monochromatic pigmentation pattern.

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    $\begingroup$ The most striking difference between the fur of a wolf and the beard (or chest hair, or really any male body hair) of a man is that from the point of the wolf the beard of the man is strangely made up of only the contour hairs, completely lacking the soft and dense underfur layer. A wolf's (or a bear's, or a fox's etc.) fur is very different to the touch from a man's beard. $\endgroup$
    – AlexP
    Commented Apr 22, 2022 at 12:33
  • $\begingroup$ @AlexP -- As I said, there are different qualities of hair! You'd pretty much have to walk up to a bearded human and a bearded Werewolf and get all up close and personal with their facial hair before any kind of suspicion of werewolfery would be raised. Frankly, I'd be more suspicious of a random person going around stroking people's beards... $\endgroup$
    – elemtilas
    Commented Apr 22, 2022 at 12:36
  • $\begingroup$ Yeah, but the question explicitly includes tactile feeling. $\endgroup$
    – AlexP
    Commented Apr 22, 2022 at 12:38
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    $\begingroup$ That article is a red herring. It says there is no defining difference between hair and fur. They are all fhuair. However there are still different types of fhuair and dog fhuair is different to human fhuair. $\endgroup$
    – Daron
    Commented Apr 22, 2022 at 13:04
  • 5
    $\begingroup$ Saying that "it's all hair" is like looking at my toolbox and saying "it's all metal." For instance, cats have four distinct types of hair. The soft downy hair that keeps it warm are much finer and shorter than the guard hairs that keep it dry. If this question were about cats, I could answer it (about 3 days), since I've seen plenty of cats that needed patches shaved. $\endgroup$ Commented Apr 22, 2022 at 13:38

Not Very Long

There are breeds of dog with VERY short hair. For example the majestic Wiener dog.

enter image description here

These guys feel silky and not stubbly. This is because they have about ten times as many follicles as a person by area. That also means each hair is thinner to compensate. This will give wolf-man a different stubble than human-man.

If you don't want discovery by touch, then I suggest the following legend:

When you shave your beard, it grows back more bristly than before.

The interaction of human-type skin and dog-type fur means that wolf-men who shave their beards regularly change the texture so it feels more like a human beard and not like petting the dog.

  • 2
    $\begingroup$ beard hair feels stubbly because it is cut long hair, this has a wide cross-section, a shaved dog feels stubbly. $\endgroup$
    – John
    Commented Apr 29, 2022 at 0:29
  • $\begingroup$ @John I have already covered that in the answer :-) $\endgroup$
    – Daron
    Commented Apr 30, 2022 at 13:49

Hair and fur are the same thing, but composition is important. Animals have an undercoat, humans do not.

If you say that your werewolves do in fact have undercoats, you can safely hand-wave an answer to your own question. Maybe it takes 3 days for a beard to grow in enough before any lupine elements can be distinguished, maybe it takes 5.

This would still be difficult (maybe impossible) to determine by sight alone, but a trained examiner could certainly feel the difference. The denizens of your world are aware of werewolves though, so they could have a "hair check" rule where a trained inspector examines any new arrivals in town. During a high-stress period they may even choose to lock individuals up for a few days so that they have no chance to shave.

One last note, if it's all androgenic hair, then your werewolves need to shave their entire bodies to avoid inspections. This in and of itself could get suspicious.


Beards are all different

Many hair on a human body is more complex than the hair on top of the head. The colour for example can differ. My own beard used to be more blond, is now mostly black, with random white and bright orange hairs in there before the grey hairs set in. Yet others have immaculate natural beards of one single colour. The stubbornness of a bread can also differ wildly. Some have easy soft beards, while my own is uncomfortable hard as needle stubble. These large differences can hide a large amount of animal beard hair! Maybe people in the know can tell the difference upon close inspection, but most people will not. As the question says humans do not know about them, they can probably rock beards that are so long they trip over them when playing their electric guitar and chanting in elvish.

That does not mean you're out of the woods. Strange wolfish beard patterns can be an indicator. Again, the differences in beards can hide you, depending on the time this plays out and the prevalence. At best people will think it's some funky hair patterns. They'll not cry 'werewolf' at first sign.

There's also the coats. The layers could set someone off, but this can again be overlooked at a different style. Regular cutting of the beard and keeping it as short as the most obvious other layer will nip that in the bud. What can set it off is an unusual high amount of hairs growing per square measure of skin, but that would mean you want to grow it to cover up the unusual amount of stubble.

A bigger danger is the seasons. Beards do not change much during the seasons, while wolf fur does. If a friend is seasonally rocking much thicker beards, possibly of a different colour even, it'll start to stand out. Then they suddenly start losing their thick beard in spring, making it much thinner. These are really indicators of something different instead of just a possible different beard. That means that in climates where the werewolves react to the weather, they need to shave off the beard when it changes. They might be able to get away with shaving it and lettingbit grow out, so it isn't as obvious. It is a risk though.

Other hair

The other hair is under much of the same rules, with the added benefit of people not wanting to talk about it or flaunting it about. "Does the carpet match the drapes" is indicative of the differences of head hair and the rest. Still it is easier to imagine (sadly) that androgenic hair will look too different. You can hope the taboo will prevent talking about it or knowing enough that it is noticeable. Otherwise it is best kept shaven or millimetre short.


The beards can probably flow! The differences in beards can hide a lot of the wolf beards. They might have to shave here and there and possibly colour their beards, but neither is difficult. If there's an unusual amount of hair it is better to let it grow, lest the insane amount of stubble let's people know. Maybe a few exotic wolf beards need to be always shaven short, but it really depends on the breed. Coats and undercoats can be dealt with by shaving one as long as the other, if it is visible/can be felt at all. Seasonal changes can be overcome by shaving all the time when the beard thickensor starts to shag hair everywhere. It might be grown back at some risk or kept no longer than a short humanly full beard.

The rest of the hair can possibly hide under the ignorance and taboo of such private parts. Anything that can still be spotted is best shaven clean or kept to millimeters.


The wolves can make an entire culture to hide. Their beliefs and customs are that they keep on body hair, and this culture would keep people from realizing their werewolves, especially after several years, when new members who are not werewolves join.


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