Underground Civilizations

While working with Deathawaken and Nigel on the underwater civilization essay, I got to thinking of another underrepresented environment - underground.

As such, I wanted to get some thoughts and opinions on how you think said civ would develop, what it would be like, ect.

To get started, some of the things I’ve noted:

  • Respiration: One of the biggest killers in cave systems tends to be a lack of airflow, so any civ that spends the majority of their time underground needs to ensure that housing receives some form of fresh air and remains unflooded.

  • Housing: Would they tend towards just series of tunnels, complex warrens, or closer to the palaces a lot of ants produce. I have the feeling, given the energy expenditure that building new tunnels requires, that everything would be clustered, but that’s just my opinion lol.

Anywho, anyone have thoughts? Opinions? Glaring issues with the entire concept?


Well…uh…I like the idea but uh…like in a speculative evolution book called “All tomorrows” tectonic plates moving could crush the species living underground, if they live in caves. Earthquakes would probobly be scary too.

I’d say this at least is partially cancelled out by the fact that the only threatening part of storms is the flooding, and that tornados are entirely not a threat. Also you missed something. Food. The only real source of food would be fish in underground rivers and root vegetables. That makes farming much harder, but it is still possible.

As for food, what about chemosynthesis or radiosynthesis, which both exist IRL, or thermosynthesis.
Then again, whether they’re capable of feeding an entire civilization, I’m not sure, since chemosynthesis requires constant digging or volcanic harvesting to use, and radiosynthesis requires a large vein of uranium, which is highly local; Thermosynthesis is most viable, only needing a heat gradient, but only exists hypothetically.

Another limiting factor is space, as rock is already almost as compact as it can be, meaning to only ways to get more room are to use a cave or the surface for more room. This would greatly limit the population of the civ.

Ant’s main killer, aside from people, are Paraisites (mites, Cordyceps, ect), other ants and the environment (flooding, unstable nesting medium, ect).

The planet Generator will have to make something below the soil but I see no reason why a massive eusocial species with a massive hive and tunnel network spanning the planet couldn’t be possible, you just have to watch out for revolts or building into the sea. Assuming the species has a social stomach and replates, food shouldn’t be a problem if said replates are connected just above the normal nesting system and are immobile when full. In the future they could be moved about by a magnetic system or something similar.

An earthquake may brake some tunnels but they could be redug in time and the replates will be drained for food by the trapped species, depending on the size of the species heavy rainfall may not be a problem but a flooding event will be.

Any thoughts?

Well I’d assume that an underground civilisation wouldn’t thermosynthesise/chemosynthesise/whatever themselves, but farm organisms that do.

Just like humans don’t eat sunlight but plants

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Yeah I’d take that as a given.

I would be glad to see amphibians who, before the advent of intelligence, were engaged in digging holes, and their life was similar to that of meerkats. Despite the fact that these are in fact amphibians with gill breathing (combined with pulmonary breathing), males have feathers on the tail that interfere with swimming (thus, the male winning the race (marriage games) shows that, despite the fact that feathers interfere with him, he is still good). Over time, they increase in size, also developing external gills, and from simple holes in the silt they move on to digging huge colonies, inside of which mosses and lichens grow, saturating the colonies with oxygen. Years, millennia go by… Creatures grow to about the size of a man, able to move for some time only on their hind limbs in order to free their burrowing front ones. They eat everything they can, from vegetation to fish. Some species pass to life in flooded caves near the swamp, the colonies begin to live in a new way, the forelimbs become dexterous, but, however, they mostly move anyway, crawling on all fours. The feathers of the males remain, and they develop beautiful tails, albeit useless. When the first colony settles in the cave system, after millions of years, some colonies lose their eyes, many die out, and those that live in caves with water reservoirs, despite the fact that they do not have long to go to the surface, agriculture begins to develop. First of all, I grow fungi, but, in water tanks into which light enters (they gouge tunnels above the tanks through which it penetrates there), algae are grown, which, firstly, saturate the system with oxygen, and secondly, are used in food quality. Several different races are formed in one cave, as their ancestors were engaged in different things - the descendants of farmers have dark skin, bright tail feathers, brown eyes, powerful muscles, they have no women at all. The second race are aquatic farmers, they have more graceful bodies, rather light gray skin with green patches, and long tails devoid of feathers. Males of this race are very rare. We can say that both of them are one race with gender differences. The last race was almost always in the depths of the caves, and therefore, has huge blue eyes, excellent hearing, white skin through which blood vessels are visible, as well as a fairly slender physique and long tails with a fin fold. Women of this race are considered the most beautiful. Despite the development of intelligence, they are in no hurry to switch to upright posture, although they acquire much more dexterous hands. Basically, they are engaged in crop production and hunting, but after a couple of hundred years, a brave hero gets a large herbivorous amphibian, and also brings her living children. Now, co-development with pets begins. Over time, they realize that releasing some of the blood of animals is much more efficient, and therefore, they began to add animal blood to food, but they don’t completely refuse meat, they often make meat with mushroom sauce (consists of several types of mushrooms and blood, plus salt, which one is not known). They live a long time and can regenerate many injuries, like the same axolotls as domestic animals, so their meat can be obtained without killing them. So time passes, they open fire, cooking flourishes, entire caves are allocated for kitchens, and they themselves live in fairly good conditions, without wars, since their long life expectancy does not force them to multiply much. But, there is one nuance, at a certain moment their rapid settlement began in the cave, many had to wander for a long time on the surface (for them it is like a desert) to find a new place to live, and all this is due to a sharp jump in the birth rate, which is now grows and grows. Over time, there are almost no caves left on the continent that are not yet occupied by them … I’m too lazy to write further

Mushrooms can live in caves

Mushrooms. Aren’t. Primary producers. Where do the mushrooms get food?

What about the way we determined for the cavern, chemosynthetic microbe symbiosis?

I let it slide in the cavern cause it’s cool, but there’s not enough chemicals.

We are talking about the upper layers of the caves, plus fungi, for example, lichens (the main organism is a fungus), they are calmly able to grow on a bare stone with sufficient moisture, let me remind you that in the case that I described, it is not far from the swamps, which means humidity is normal

ah okay, thought you meant something closer to the cavern forum gaem’s world

Caves are remarkably hostile to intelligence. Most caves have very little energy to work with, so the inhabitants have to make do with what they have. This results in the weak, emaciated frame seen in many cave-dwelling animals, which isn’t a recipe for advanced brains. There is also the issue of what they’d use it for. There isn’t much going on in caves, so there’s no need for any complex mental abilities to work things out