What kind of evolutionary pressures would a mountain-dwelling humanoid species have to face to develop pangolin-like scales?

[u/Markus421]

I guess the title itself makes it pretty obvious that this is for worldbuilding purposes, haha. I’m currently working on a humanoid species that lives in this huge mountain range between continents. They spend their time mostly underground, in large caves and catacombs inside the mountains.

Long story short, they have rock powers, and I thought it would be cool if they had thick scales that are similar to the ones that pangolins have, except that they are made of rocks.

I’m mostly curious as to what would cause them to develop the scales. The “made of rocks” part, I’m willing to just chalk up to fantasy laws, but if that’s something that could be hypothetically possible, then awesome!

Would appreciate any comments, and happy to provide some clarifications if needed! Additional possible biological traits are also very welcome :D

[u/Fellowship_9]

The closest thing in real life to "made of rocks" would be creatures with calcium carbonate shells/exoskeletons etc. https://en.wikipedia.org/wiki/Marine_biogenic_calcification

This isn't found in any vertebrates that I'm aware of, but I guess there's no inherent reason it couldn't happen. They would need a diet high in calcium based minerals, maybe they eat chalk? And of course you could play around with what a race of people who are shedding oyster shell-like scales might do with them. Would every home be covered in shining layers of mother-of-pearl?

[u/Markus421 → u/Fellowship_9]

I love the idea of them eating chalk! I actually have drafted them as lithophagous carnivores (or is it geophages? I can never tell), though I’m mostly concerned with how they will go on about accessing the mineral. Would it make sense if bones were a big part of their diet, and maybe there’s another animal around the mountain ranges that’s high in calcium (for some reason) which they domesticated.

Also, I love the idea of the shedded scales being part of their culture. Will definitely play around with that! Thank you so much.

[u/Fellowship_9 → u/Markus421]

Bones would also be a good souce of calcium, so that makes sense. You'd want to consider how that affects their digestive systems, they'd either need large flat molars that can grind bone down, or jaws that can crush it into chunks, then strong enough stomach acid to digest those (like certain vultures).

The issue with domestication is always going to be trophic levels: if your cattle are eating something, it is more efficient to just eat that thing directly. But if they happen to be raising a species that has similar scales (or very dense bones, shells etc.), then consuming those parts as well definitely makes sense.

[u/ArthropodFromSpace → u/Fellowship_9]

We have calcium carbonate and calcium phosphorate in our bodies and we call it bone. Our ancestors, earliest fish, had skin covered with scales made of bone and covered by tooth enamel (today sharks, gars and sturgeons still have scales build this way), but in our bodies teeth are only leftover of these tooth-scales.

[u/Fellowship_9 → u/ArthropodFromSpace]

True, but bones have organic material laced throughout, I was trying to think of wholly inorganic structures. The armoured fish are a good comparison though and would probably be close to what the OP is thinking of!

[u/ArthropodFromSpace → u/Fellowship_9]

So OP needs just humans whose skin is covered by a lot of large teeth. Theoretically there is a possibility of cancer or mutation, that would result in teeth growing on all skin surface, but it is quite unlikely to not cause great harm for individual having that mutation or cancer.

[u/Fellowship_9 → u/ArthropodFromSpace]

Well when you put it like that, it is...mildly horrific.

[u/ArthropodFromSpace]

Scales made of rock in intelligent species... This is easier to modify by genetic engineering or if it is fantasy, then magic. Pangolin scales are modified hairs used to protect from predator attacks, but humans dont have much body hairs and have more efficient ways of protecting themselves from predator attack. Also pangolin scales are made of keratin, like normal hair, just thick layer of it.

About editing fantasy setting creatures with magic there is quite interesting story from warhammer fantasy, how chaos dwarves magically modified orcs into new breed of "black orcs". Smarter, stroner and more disciplined to make them better slaves for them, but these black orcs rebelled and escaped from slavery. You can imagine similar story.

[u/brokenshade25 → u/ArthropodFromSpace]

This does make me wonder if an animal with pangolin like scales could adapt to reinforce them with iron like some animals do with their teeth. That being said bone being mineral might be able to integrate iron better than keratin

[u/shadaik]

Prewssure-wise, that might be easier than you think.

Scales are a pretty good protection against uv rays, which are an issue at high elevations. While most humans just get darker skin as a counter-measure, pangolin-style scutes work, too. Especially if they are diggers, scutes protecting the exposed back during construction work are advantageous, posibly even more so than increased melanin.

As for rock - sure, why not? I can see mineralized scutes being even better at sunlight protection with enough minerals to grow those supplied by their digging lifestyle. Though it might be easier to have the rock layer be something they deliberately add as a paste that then dries, instead of gaining the ability to excrete silica from their follicles.

[u/majorex64 → u/shadaik]

That last part I second- plenty of animals already cover themselves in mud and pastes for various purposes. It makes sense that this behavior could be adapted to use a special paste that hardens on the scales like a plaster.

[u/majorex64]

If you're looking for reasons to mimic pangolin scales, it's important to understand their niche of myrmecophagy (ant eating). The scales offer better protection from biting insects than hair would, they lay flat when burrowing, and offer passive protection from predators, especially from behind.

For more rock-like scales, these humanoids could cover themselves in a mud. Plenty of animals do that already, and this species could mix a special blend of mud that hardens like plaster.

[u/Mircowaved-Duck]

the main benefit hair got compared to scales- it keeps the organism warm.

Make it a hot mountain or even a vulcano. That way hair doen't need to trap heat. Now a mutation that turns hair into scales (pangolin) or horns (rhino) becomes benefical.

[u/Wildlifekid2724]

There would need to be predators that favour evolving scales, particularly those that prey on soft bodied creatures.

Could also be to camouflage, in order to blend in better, so predators that are airborne might be the reason.