In typical fantasy novels, the dwarf civilization lives within mountains and is known for mining. But if a race of sentient people really did live largely underground in mountains, what characteristics would they likely evolve?

Let's assume this race is mammalian to narrow things down.

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    $\begingroup$ A related question "Could a Dwarven Civilization really exist?"- worldbuilding.stackexchange.com/questions/9947/… $\endgroup$
    – CoolCurry
    Commented Apr 19, 2015 at 16:22
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    $\begingroup$ Are you looking for adaptations purely related to living underground in mountains, or specifically for adaptations for bipeds 4 feet tall? $\endgroup$ Commented Apr 19, 2015 at 16:32
  • $\begingroup$ Purely for living underground in mountains. $\endgroup$
    – CoolCurry
    Commented Apr 19, 2015 at 23:14
  • $\begingroup$ Would you object to the question being changed to "What would be the evolutionary adaptations of a mountain based subterranean fantasy race?" $\endgroup$ Commented Apr 20, 2015 at 15:06
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    $\begingroup$ Remember that it is a LOT easier to lose unneeded genetic info than it is to gain needed genetic info. So (using some ideas from answers), it's easy to lose color vision, height, hair, and pigment. It is hard (but inconceivable) to grow extra digits, thicken fingers and nails, become more muscular, turn whiskers into sensory hairs, and develop heightened hearing/smell/touch. It would be pretty farfetched to have humanoids develop "pickax hands." $\endgroup$
    – dmm
    Commented Apr 20, 2015 at 17:20

6 Answers 6


One important question to ask is, at what point did these creatures begin their underground lifestyle? Did they develop tools, lighting, and social structure beforehand, or have they been burrowing since before they were sapient? This may actually result in very different forms, depending on how well they were able to modify their environment to account for their lifestyle.

If they were a group of humans that moved their civilization underground, they might actually wind up shaped not especially different from your typical fantasy dwarf. Small size would allow them to save on time and energy by making smaller tunnels, and a stocky build would make them proportionally stronger, which is helpful for digging through rock. If they had artificial lighting already, they might develop better night vision and more sensitive eyesight to allow them to see better with the sparse lighting they have available. They probably would not experience the more extreme types of evolution, since they would be able to modify their environment through technology. The way their culture evolves, however, would be interesting to think about.

If they started out as underground creatures, however, they might wind up with very, very different shapes. If they lived deep underground, with no access to any light at all, they would probably lose their eyesight altogether - unless they went the opposite way, and developed bio-luminescence instead, possibly by forming a symbiotic relationship with an existing bioluminescent organism. They would probably not remain bipedal for very long, as burrowing animals typically use either their front legs or teeth to dig, and without tools the benefit of standing upright would quickly be lost in a subterranean environment. As is the case with ferrets, weasels, and burrowing lizards, they would probably end up with long, flexible bodies and stubby limbs adapted to burrowing rather than grasping. It is difficult to imagine how such creatures could develop civilization in the same manner as humans, although they may discover fire through sulfurs and pyrites. A race of intelligent mole-like creatures who developed chemistry before they learned to make tools would be very interesting to explore!

Some adaptations that could apply in either case could include thicker skulls (which could protect them from falling rocks), slower metabolism (to account for lower access to food and oxygen), and thicker, more durable fingers. Their ears may experience some very interesting adaptations; on the one hand large ears are vulnerable to damage, on the other hand good hearing is helpful in low-light environments, and they may well develop some kind of sonar ability. They may also lose color vision, which is unreliable without a great deal of light, and would probably lose most of their skin coloration within a few generations, which would both help them perceive each other better and would be less of a problem in a world without sun. If they used fire, an ability to detect explosive gases instinctively, whether through smell or sound, would be very helpful. Hair is a toss-up; on the one hand body hair can become full of dirt and dust which may make clean living in underground areas a problem, on the other hand thick body hair can offer an extra layer of protection from scrapes and bruises, and long whiskers can even double up as a sensory organ as it does in the case of cats and rodents.


It's pretty dark deep down in the mountains.[citation needed] So I decided to read about moles.

Moles . . .

  • Have an extra thumb on each hand.
  • Love to eat worms and other invertebrates.
  • Do not have good eyesight (they don't need it).
  • Are not too social.
  • Can breathe more CO2 than other animals.

References: Wikipedia, BBC, Wildscreen Arkive.

I would bet that dwarves would have some of these qualities. They might . . .

  • Lack good eyesight, but have other highly-developed senses, such as smell and hearing.
  • Have a higher tolerance for CO2.
  • Enjoy eating things that live underground (though not necessarily worms).
  • $\begingroup$ there are echolocating humans right now! $\endgroup$
    – josinalvo
    Commented Apr 19, 2015 at 22:59
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    $\begingroup$ see npr.org/2011/03/13/134425825/… $\endgroup$
    – josinalvo
    Commented Apr 19, 2015 at 23:00
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    $\begingroup$ I would argue that they would have better eyesight, at least in the dark. If their evolutionary adaptation happened post-sentience (for example, if their ancestors moved into the mountains), then they would always have some light source. They would just get used to not needing very much light. $\endgroup$
    – David K
    Commented Apr 20, 2015 at 15:01
  • $\begingroup$ It was my understanding that moles have very sensitive near-sighted vision, but lack far-sightedness. $\endgroup$
    – Zibbobz
    Commented Apr 20, 2015 at 16:25
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    $\begingroup$ Maybe Tolkien's dwarves are like naked mole rats, with one breeder and many workers. Would explain the lack of obvious females. Maybe Gimli and Thorin and company were non-breeding females! $\endgroup$
    – dmm
    Commented Apr 20, 2015 at 17:23

They might lose pigmentation, too.

They might have an ability to interpret passive sonar: The banging of mining would echo and reverberate, giving them a sense of the details of the passegeways and siesmic tomography of the solid rock.

Is the humidity high? It might depend on the mine. They might have trouble keeping cool, especially with activity, so maybe have low body temperature and depend on it, and find open space uncomfortable, and need physical activity to regulate their body temperature when awake. That would feed back to their work ethic.

Assuming they need some light to work, torches are problematic. Lanterns developed that run on minerals (limelight) or bioluminescence or semi-magical glowrocks.

They might be mistaken for vampires. I got an image like Nosferatu


Creatures that live underground also change in other ways.

Your Dwarves might develop sensory hairs and whiskers to augment their sense of touch and ability to sense the size and shape of the enclosure they are in. Since they are in small enclosures, they may have devolved things like collarbones, to make them more flexible and able to move through tight passageways.

Many burrowing animals have long, flexible bodies. Ferrets are a good example of this, so your Dwarves might have very odd proportions. Since they are digging in a pre mechanized age (and have been for generations), they might also have developed a body plan and musculature similar to badgers, to assist in digging. So long bodies and short, powerful limbs for digging.

Most of their body openings will also need to be protected from abrasion and the accidental ingress of dirt, so look at biology to see the wide variety of flaps, covers and protective membranes that creatures have evolved for the underground lifestyle. Your Dwarves will probably have a few of these adaptions as well.

Humans and sentient creatures from above ground might actually find Dwarves horrifying or repellent to look at or be around if the Dwarves have evolved in these ways for an underground existence.


A great question with a lot of alternate answers. There are no permanently tunneling large mammals on earth. This is mainly due to food supply, the energy it takes to burrow, and the amount of oxygen available underground (even with the moles ability to recycle a small amount of oxygen they still have to surface to stay alive). So unless the subterranean food chain of the fantasy world was more complex (contained larger species to be hunted by the dwarves) the dwarves would either have to be semi reliant on above ground foraging/farming, or have evolved unlike other species on earth. Alternately they may have discovered methods for farming underground flora and fauna.

  • $\begingroup$ Tolkien solved this by having his dwarves mostly trade for food (as human miners have always done). $\endgroup$
    – dmm
    Commented Apr 20, 2015 at 17:24
  • $\begingroup$ Large natural caverns would provide a reservoir of oxygen, if there are oxygen-producing non-photosynthetic bacteria (e.g., www.mpg.de/621120/pressRelease201003241). $\endgroup$
    – user243
    Commented May 2, 2015 at 15:03

They live underground, where by definition there is not much light, so look to animals like moles and badgers who live underground for evolution.

Both have:

  • bad eyesight
  • good other senses like hearing and smell

Dwarves are typically a mining species, so they would also need to be strong enough to

  • swing a heavy pickaxe
  • carry mined loads of material out.

You may also want to consider that if they use pickaxes so much, they might end up with one integrated into their body. If not a pickaxe itself then certainly something that makes them able to dig without the aid of a tool.

  • $\begingroup$ "You may also want to consider that if they use pickaxes so much, they might end up with one integrated into their body." I think this would only be the case if they started digging before developing tools. At that point, I imagine they would end up like moles with very long claws that they dig and scrape with. However, I think waiting until tools develop is necessary for any decent depth digging. $\endgroup$
    – agweber
    Commented Apr 20, 2015 at 14:26

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