lumateranlibrarian:

cygnahime:

curlicuecal:

thepioden:

cygnahime:

Hey, biology nerds! I know you’re out there, lurking, knowing facts.

If you were watching an underground/mountain-dwelling humanoid species evolve, like say, fantasy dwarves, what biological traits would you expect them to develop that are unlike those of humans?

For that matter, what might tall, desert-dwelling elves look like? Or small, hill- and forest-dwelling hobbits? I’m trying to get to something a little more interesting than “tall human”, “beard human”, and “short human”.

Dwarves: 

• Tapetum Lucidum
• Third eyelids, if they do a lot of digging. Related, ears and nostrils that can seal – keep that loose dirt out of the mucous membranes!
• Beards? Try vibrissae, or electro-sensitive or motion-sensitive hairs
• Low body temperature and poor thermoregulation when above ground – use it or loose it re: high metabolic costs, and your underground environment doesn’t swing wildly
• Related: increased photosensitivity
• A mechanism for torpor or severe reduction in metabolic activity. This is a common adaptation in cave-dwelling and fossorial mammals, probably related to the thermoregulation thing above, and also the low oxygen concentrations and irregular food sources than can be available underground. tl;dr dwarves can hibernate
• Something Weird and Off about upper arms and shoulder joints and musculature – digging requires a bunch of morphological specialization of the upper arms to be remotely energy-efficient
• The ability to do that terrifying mountain-goat thing where they can scale and balance on 90 sheer vertical cliff faces

Elves: 

• If it’s a hot desert, dial the elf-ears up to fennec proportions for excess heat venting. Sweating is an inefficient use of water. Panting is better for evaporative cooling. 
• Very long, very dark, very thick eyelashes
• You can actually re-use the third-lid and sealable nostrils and ears mentioned for dwarves. Keeping out sand is important!
• Tolkien-hobbit-equse feet: large, flat, with unusually thick soles, if they’re walking on hot, shifting sand. 
• Some animals will ‘cry’ excess salt through specialized glands near the eyes, to either fix salt balance (seagulls) or to avoid wasting water in urination (roadrunners). Your main goal re: desert adaptation is water conservation, which means figuring out how to avoid peeing whenever possible in many cases. Mammals usually will concentrate uric acid into a pellet or paste, but the idea of elves with bright-white, reflective salt-lines down their faces is Aesthetic™ as hell. 

I’m gonna lean on bug biology here cuz why not.

Underground dwarves:

-specialization to oxygen levels at different depths (can’t move easily between them?)

-daily and seasonal thermoregulation via moving higher and lower in the ground (or even into sun-catching, above ground mounds or mountainsides)

-vibrational hearing/communication through substrate? vibrational prey-seeking

-farming of fungus/aphids/ etc on plant root structures

Desert-elves:

-strongly nocturnal or crepuscular (dusk and dawn) activity cycles

-sensitivity to UV light— can feel/see it with their skin. helps them stick to shadows.

-seal the fuck out of any avenue for water loss

-burrowing

-postural thermoregulation by holding body far away from heat reflecting ground in day, close to heat-retaining ground at night

-some beetles stick their butts up in the air and absorb water vapor that way, that’s pretty fun

-estivation (summer hibernation)

Forest Hobbits

-Thicker pelts (fur or skin) to deal with undergrowth

-Food gathering and underground food storage

-Hibernation in cold winters, extra fat gain during warm season

-Climbing/arboreal

Thank you! Fascinating hobbit thoughts. Also elves just…slouch at night.

A great (if comical and sometimes kinda disturbing) example of dwarves that have evolved to be suited to underground life can be found in the Artemis Fowl series by Eoin Colfer.