Otdfbt

Recently I was talking with a friend of mine on fantasy stuffens. I brought up that its interesting that dwarves are rarely in the desert and he immediately listed reasons why the dwarf build is bad for the desert: Short stumpy legs are bad for the desert and horrible heat dispersion made worse by the massive beards.

But how could the common fantasy dwarf (short stocky and with a big beard) adapt to a desert environment? What kind of physical changes would be necessary for this change in environment?

Note:

I don't want to lose too much dwarfiness so if possible I'd like to retain at least being stocky (although thinner then the usual dwarf) and having big beards.

The social and architecture changes will be a later post.

This is a slow gradual change from the proto dwarfs that wandered into this desert so you have a large time scale to work with.

Primary issue with living in the desert is lack of water.

Dwarven build is well suited for storing water. Their round bodies with healthy amounts of fat should store lots of water. Low surface area should reduce loss of water. Dwarfs are generally said to like working at a forge, which implies they can tolerate hot conditions fairly well without sweating insane amounts of precious fluid.

Sleeping underground where the temperature is stable during the day is a common adaptation by desert animals. Dwarves are excellent at digging and prefer to sleep underground anyway. Your desert would be full of burrows where the dwarves sleep during the day.

Desert animals commonly prefer to be active during the night when it is cold and less water is lost. Dwarves see in the dark and their wide forms are well suited to resisting the cold. They'd adapt to being nocturnal very well.

In short, dwarves are extremely well suited to living in the desert as is. Much better than humans certainly.

Stocky creatures can adapt to a desert, they'll use their stockiness to store water. So these dwarved will be weaker than regular dwarves: theit bodies will have less bone and muscle fiber, and more tissues that can store water for long periods.

As for the beard, theirs will somehow accumulate static charge. The hairs will repel each other, exposing more hair to the surface.

(I just googled for "zapped beard")

This way their beards actually become excellent for heat dispersal!

I think there could be at least three different scenarios for 'desert dwarves'.

First, if the dwarves were already formed as a species and had culture and tool use by the time they came to desert, I do not think they would change much. As many other answers here tell, sapient creatures do not adapt to the environment too strongly - they have tools to take the edge off the environmental pressure. Most what would change is the skin and hair color and eye shape.

The second scenario is a scientific 'common ancestor' approach - evolution in your world works pretty much the same as in ours, without magical interference. 'Dwarves' are sapient humanoids evolved from the desert-dwelling burrowing primates. I do not think they would retain all the adaptations of their burrowing ancestors - those were much more adapted to desert. I would say, they would be something like humans, if humans evolved from desert nocturnal stalking omnivores instead of savannah endurance omnivores. Shorter, with more strength and less endurance, possibly big ears, broad and soft feet, and more body fat. I do not know about beards - I'm not up to date on the evolution of human facial hair. Such creatures would since then spread out from their ancestral deserts and live in other environments too.

The third scenario is 'intelligent design' - some magical or scientific power had consciously worked on adapting human or dwarven baseline stock to desert. That power would most likely go overboard and try to create an ideal 'desert-dweller', cramming as many features from different desert animals as possible - here you can just let your imagination run wild. Just take all adaptations from the list here - http://mentalfloss.com/article/57204/20-amazing-animal-adaptations-living-desert.
They would have very variable metabolism, being able to slow it down significantly. A lot of fat, possibly in the form of special humps. Closable nostrils and additional eye memrane like camels, different water exchange as in some dessert antelopes (say, they don't need much water and don't urinate, instead expelling uric acid as solid). These creatures would be actually overspecialized for desert, so it would be hard for them to live in other environments.