An ecological dungeon

We have all seen articles on how Dungeons don't work. I've seen such articles before. But this time, an idea struck me: Why not do a dungeon that really works? Where creatures live their lives in harmony; just the right ecological way?


I have seen articles complaining about the traditional dungeons being too concentrated on killing some monsters and collecting treasure, ignoring things like ecology and common sense, monsters only wait on you till you kill them...

I've seen such articles before. But this time an idea struck me: Why not do some dungeon that really works? Where creatures live their lives in harmony, just the right ecological way?

Bad example: Lionel the Lich creates his fortress. For being that evil little life is there, populated mostly by undead and magical creatures. Cool, dungeon works, ready to get slaughtered. No problems with ecology 'cause no life there, see?

But I have another reason: don't want to drag my heroes around to find new dungeons every day. I want to use the same dungeon more times. So I need a dungeon that can regenerate.

What's that dungeon I want, anyway?

* Traditionally it is underground. Is usually connected to the outside world. (maybe somewhere deeper too...)

* Though some corridors and rooms may be digged, it is mostly a set of caverns, big enough to have some kind of ecosystem.

* Connected to Upside: means some common life-forms, like bugs, rats, and bats. And others.

* Connected to Downside: if your world allows it, can mean any exotic life forms out of the Deep

* Some source of magic may care for even more exotic creatures


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Rats, our friends. They are our company for centuries. A single rat is weak, but a horde of rats can survive much, and with incentive can be a nice foe. Hard living in free nature, but in closed enviroments, like sewers and dungeons, hmmm...

Rats excel underground in many ways. Senses, orientation, agility. Can eat basically anything. Is very social in its own way, and cunning.


Eats basically anything, makes a handy base of the food chain for that predators. The default dungeon encounter.

Ecological Purpose and Others:

If a dungeon has rats, you can forget any food lying around. Same applies to scrolls and potions, which are sooner or later consumed, or at least tried. Even putting them into wooden containers like chests or crates may not be enough. Rats are smart and can learn to avoid poison, so food just lying around in a rat infested dungeon should not be eaten. Contrary, not all that rats eat should be eaten too. Be carefull, rats spread diseases!

As for rats themselves, dwarwes are known to like their taste (ewww...). If you are THAT hungry, it is recommended to cook or roast them, though. Ask dwarwes for recipes.

Various monsters may survive on rats, while waiting for something tastier (like you).

Wild Dog, Small

Wherever people settle, they make sure they kill any wolwes, sooner or later. They bring dogs with themselves. And sooner or later, some dogs get abandoned, lost or ignored, and if they survive, they can attempt to fill a wolf-sized hole in the ecosystem.


This small canine is usually the size of a small dog (for big stray dogs get killed). Living on the verge of society forces to be silent and not attract attention, living of others leftovers. Hunt they still can, but only small rodents fall prey to them, they are mostly scavengers. Is usually a crossbreed of other small dog breeds, a bastard.

Mostly roam in small groups, or individually. Can be easily scared off by any creature bigger than them unless it is obviously too weak. Depending on their experience may attack weak-looking humanoids, or sleeping ones, or not. But most probably will avoid confrontation with ANY humanoid they meet.

Living space:

Slums of greater cities, and surprisingly even those dungeons - holes filled with monsters smaller and bigger. There they hunt rats and have occasionaly rests of something bigger. Are likely to follow heroes, wait till they kill something and leave it so.

Never far from the civilisation. Would not survive in a serious confrontation with a real predator.

Ecological Purpose and Others:

A minor scavenger and hunter. Would eat undead only if starving.

A minor non-threatening encounter in a not much threatening enviroment. Mentioning to heroes it is a dog, however dirty and poor, may save its live.

1% chance it is a pure breed, possibly in some way valuable. If carefully approached and treated, may be befriended and trained as a guard dog.


None. May use small holes as lair, where they consume their pray. Only if you need bones.


The Silent Flyers

No cheap horror movie or dark place would be complete without them. The flutter of their wings, and perhaps their sounds (if you got some ability for it) make them mysterious, dwellers in the dark, silently waiting to suck out your blood (Booo!).

If I remember right, the friendly bats live mostly on insects or fruit juices. There's also a variety that likes blood, but that's not a vampire. It is dangerous to sleeping cattle, if to anything. It bites it near some vein on the neck or back, and licks the blood flowing. Little dangerous, but it somewhat weakens the animal, or may transfer diseases. Fantasy mutants may be of course bigger, and more dangerous...

Ecological Purpose and Others:

One of the bases of the traditional underground kitchen, said to taste like chicken if you catch a nice fat one. Also one of the traditional alchemystic ingredients.

Bat's droppings can make the substrate for any weird fungus, bats may feed that bizzare monster next door... still hungry enough for your heroes.

Traditionally (in RPGs) they attack people with sources of light if disturbed. Not too sure about this, but we can leave it so.

Live on insects, fruit-juices, sometimes even on bodily fluids of higher mammals. Require enough place to fly around, if at all possible a connection to the Outside.


(Knowledge Skill)

Given at least a week's careful observation of certain animals and creatures commonly living undergound, on a given location, you get insight into their life. Succesfull use of this skill may give you knowledge of following things:

- locations they evade for some reason (dangerous places, lurking monsters, leaking gases, danger of a cave-in)

- their behaviour may indicate various changes in the local ecosystem

(something scared them, a new threat, earthquake approaching, adventurers arrived, ...)

- can possibly lure them to locations of your choosing, for various purposes

Fore-warning is a very good thing. Hermits living in caves are likely to have this skill, even a smarter Orc could have it. Don't be surprised when the mysterious man is not surprised at your coming. I've been expecting you, come in...


Bugs you will eat, and bugs will eat you.

Insects were here much longer than we are, and will be when we are forgotten. Practically any ecosystem makes use of insects, in numerous roles. Most dungeons should have THINGS creeping in the corner, on the wall, floor and ceiling, everywhere. Remember Indiana Jones and the Temple of Doom, the girl and thousands of insects? Cute.

Ecological Purpose and Others:

Eat anything and get eaten very often, handy. Should you try to eat them, choose carefully. Some are poisonous, some may be a local delicacy. Some may a kind of alchemystic ingredient.

Bugs get often magically enlarged in size, to play cannon-fodder for the heroes. They are well suited for this, being not much smart and using mostly simple forms of attack. If I remember right, spiders fall also in the Bugs category, once enlarged and armed with webs, many a DM's favourite!

Another option is to use a swarm of them little bugs... It's a kind of honour to be eaten by a dragon.

What ate him? Ants? Hm, bad luck. What was his name again, can't remember it somehow.

Unless poisonous, individual bugs can be just ignored. A swarm can be mightily dangerous.

Similar to rats, insects are likely to devour much of the perishables, and some of the more enduring items, too.

The Green Stuff

The true base of the food-chain are the molds, lichens, mosses, funghi etc. They grow on the ground, walls and ceilings, produce oxygen and in some cases light. Various varieties have many other functions, some actually climb up the food chain to consume insects or hapless adventurers.

Dungeon greenery is usually hardy and adapted to its enviroment. In the long run, they can survive most threats of this enviroment: stomping monsters, adventurers digging their way somewhere, even fire and explosions, or poisonous gases can not truly erase them. So even fully blasted dungeons would have some remaining. Plants do survive.

There may be a few places where nothing lives. Tombs sealed for long years, without any light or fresh air would be truly dead. Where plants cannot survive, few other life forms dare.

Ecological Purpose and Others:

With light and a good substrate (varies, some can survive on almost anything) produces oxygen (a gas good for breathing, requirement for many creatures). Some varieties are rumoured to shed weak light, and in large colonies may illuminate even great caverns, thus helping many other life forms.

Plants may contain both useful and harmful substances. Some are very valuable.

Ohhh I agree with your opinion. It makes sense. Animals to not just exist to kill the adventurers. Some may just ignore the person till the adventurer provokes them. Not all look at humans as a food. Some may actually be nice.

Blue Stalactite.

What an odd thing this is. This is a stlactite that is blue. Yes, blue. It is made of little bacteria. The bacteria eat the Minerals in the cavern cealing and as they grow they form a saft structure that looks like a stalactite. They are known for having curative properties if applied to wounds. Many animals in caves are known to rub against these when wounded.

Fever Crabs.

These crabs live in large colonies that look like scales on the ceiling of the cave. Their pinching claws will cause people to have a fever for a few days. They eat blue stalactite. The colony actually mines tunnels in the ceiling to give minerals to the stalactite which they in turn eat. Though not aggresive they will attack any who touch the blue stalactite. They keep the blue stalactite from over growing.

(While this may not fit exactly the Dungeon theme, it shows a way how a quick-and-easy ecology might be cooked up, and even seem logical, hopefully.)

My players wanted to hunt on squirrels, so I needed to know more about them. Of course I could do serious research, but hey, why should I not pull it all out of thin air?!

Here we go...

Silver Squirrels are for the biggest part of the year very similar to ordinary squirrels. They may be a bit bigger, though. In autumn and winter their pelt turns to a rare silvery shade, and that's a good reason to hunt them.

But now, what's the point of changing the colour? The usual brown or black seems to me a better protection in the average forest. It might be better in winter... but squirrels merrily hopping on snow reminds me too much of Ice Age (a nice movie). But the rumour spoke of no average forest, and Crooked Forest may be different. So why go silvery?

Maybe some tree turns its leaves or needles to a silvery hue. But why? Green is supposed to be better for photosyntesis, white does not sound that good to me. And in winter is dark colour probably better, because ummmm???, because capturing the few sun-rays keeps a tree warmer, and reduces frost damage. I have no idea if it is true, but let's stick to it. And why would a tree want to freeze even more? Maybe it wants to get rid of worms and other nice little biters.

Now, trees tormented by insects do (if I remember right) simply grow over it, or improve their chemical defenses, or both. And if a particular tree-type falls as prey too easily, it will die out. So what is its ecological edge, and how does it survive in large enough numbers to have a species adapted? Hard to explain with the little knowledge I have about Nature, so let's insert something, that has a tendency to move outside of logic: Humans.

Humans, or humanoids in general, cut down trees to make homes, baseball bats, and firewood. They like especially the great tall-grown trees, and wood is a nice decoration anyway. With this approach, trees have a tendency to vanish.

What if one particular tree, let's say a pine tree, adapts to an influence other trees fail to? First, it might support the little feasters that ruin its wood for building purposes, hopefully killing most of them every winter. It may also change its way of growth to produce mangy, knotted, twisted forms, to resist axes better. A limited way to resist fire would be also useful now, for humans will dislike this ugly useless tree.

There we have it. A location with squirrels is now connected to history. It presumes intensive deforestation in the recent past, and creates attitudes and superstitions for the locals ('Don't go into that forest, kids! They say that every White Pine was a witch a long time ago... and some of them have a very light sleep... '). Now that lumbering has ceased, and few go into those ugly woods, the forest may have not only squirrels attached...

Undead (see also a more expanded discussion of this kind 2793)

Lesser Undead are commonly found in dungeons. For now let us ignore what they do there and how they got there, let us think about how they interact with local ecosystem.

Undead are not alive (by definition). They are more like life-reversed. They do not like the Living, and the Living don't like the Undead much either.

Undead see Life. They see other undead too, but they can see life's energy in those yet living. According to some sources, they gain nourishment from killing life (not to mention flesh-eating ghouls...). So do they destroy anything living around them? No.

Some hardy mosses and lichens actually survive on undead. The zombies don't seem to object. They don't seem to object to small creatures either: insects, bats and rats live freely where zombies do. How to interprete this?

A) They don't like life, but their hate goes against humanoids. Sounds logical, for they were humanoids, too. But what about undead animals, why do they attack humanoids? Reason may be a built-in programming, or the fact their creator is a humanoid.

B) They hate life, but they ignore minor living forms. Or they are not able to concentrate on the creepers, their life force being too weak.

That means free-roaming undead cannot happily live next to a cave-bear, nor any other large animal. In the long run, only one side could stay or survive.

Also might mean that undead can be bypassed, if you disguise yourself (through magic) as a little creature! Question is, whether it disguises your life force enough, too...

Ecological Purpose and Others:

No built-in ecology (undead). Minor life forms are free to live, greater life forms are attacked. Unless commanded to do otherwise, they do not move much, or move not at all.

Are seldom attacked by other dungeon denizens, and if then certainly not for food, being not much tasty or appealing. Another useful kind of cannon-fodder, they can wait a long time for any hero.

? Responses (12)-13

Goto Author

This codex/ scroll is worthy of note

Goto Author

And this is a shameless bump, as this codex could be of interest to those of the dungeon persuasion.

Goto Author

Updated: Hey. The guy that has reposted this from the forums has forgotten the part on undead! Shame on him!

*slaps himself with a large trout*

Goto Author

That was because there was only ONE post on undead, not enough to make another Ecological Dungeon thread.... Until I made one (and did three more posts).

There is other good stuff that the owner of said thread (or owner of said post) did not think was worth transfering after the initial transfers were done.

Goto Author

No, everything of that thread is posted now - some posts were just made submissions of their own.

Goto Author

A good Scodex that needs more :)

Goto Author

This article makes sense and is a good starting point for creating an nice dungeon.

Goto Author

A noteworthy and useful scroll/codex. Anything that makes you really think about your worlds and how they operate is valuable, and this one does a great job as spurring that discussion.

Goto Author

Nice codex, but it could definitely be expanded. I know that a lot of monsters wouldn't necessarily fit into a normal cave system or dungeon, but adventuring parties rarely bother with 'normal' caves. What kind of monsters *could* survive in this environment, without breaking the ecology you've established?

I think that's why Tolkien's goblins and trolls made so much sense. They were smart, resourceful, and fully capable of exploiting their environments to eke out a living. Dragons and other large reptiles might work, but only if they were warm-blooded and able to hunt frequently (or could easily exit the cave system to hunt). Smaller reptiles, amphibians and even fish could thrive in such an environment, but without a source of light their eyesight would likely be poor, and without heat, their movements sluggish.