September 22, 2023

Better Underdark Ecology: Bat Farms

I really like dwarves. It’s hard to explain, but I just find them fascinating. When I’m driving through the foothills near where I live, I fantasize about the dwarven strongholds deep beneath them. I imagine their trading caravans carrying goods into and out of their settlements. When I can’t sleep, I think about them crafting wonders under the mountain. Now that we’re returning to our series on subterranean ecology, I want to focus a bit more on some ways to think about how the dwarves might address their food supply.

We were going to get here eventually, so I guess I’ll just dive in: the main source of food into a cave system is bat poop (or guano to be precise). As we discussed in our last article, the problem with the underground food chain is that there’s no light for plants to photosynthesize and thus no foundation for larger creatures to subsist on. Bats solve this problem when they leave their home caves to feed. They fill up on fruit or insects and, with their bellies full, bring those nutrients back to the darkness. In many caves, the sheer volume of bats creates a layer of dropping several feet deep. Of course, guano is prized for its potency as a fertilizer, but it’s also a buffet for many creatures. Bacteria and fungus grow in the guano and provide food for troglobites like millipedes, crustaceans, and salamanders. In D&D, this underground food chain could extend out to monsters, like purple worms and ropers.

As you can see, bats are critical to life underground and life underground is critical to dwarves. Ergo, dwarves would have every incentive to spur this process along. So, what if dwarven bat farmers were a thing?

It’s not hard to imagine dwarven farmers breeding and raising bats in colonies near the surface; Beautiful, ancient masonry juxtaposed by the pungent smell of a barnyard. Burly workers with thick leather gloves expertly tend their animals. The precious guano is harvested and brought farther into tunnels to provide a food source for other forms of livestock. And to get weird with it, like we love to do at Charmstone, bats are mammals. So it’s possible that dwarves cultivate and enjoy bat’s milk. Aside from guano production, maybe they also breed and trained attack bats to scout for orc or goblin reading parties encroaching on their territory. Or conversely, fluffy domesticated bats are bred and sold (for a tidy profit) to the dwarven nobility as pets.

Guano can also be used to make explosives. Seeing as dwarves are renowned for their excavation and tunneling skills, it’s highly possible bats are their secret weapon. If your gameworld closely resembles the Warhammer one, it’s quite possible dwarves invented gunpowder weapons. It’s more than likely that these farms would critical the production of black powder. 

Like I mentioned previously, guano is often used as a fertilizer in our world. This could be an interesting contact point between dwarves and other humanoids living near their settlements. Excess guano could be traded to nearby civilization for use in above ground farming. Starting an adventure in a tavern might be old hat, but what if that tavern is situated on a dwarven guano trading hub? It would be a perfect situation to meet a group of halfling beet growers, an orc envoy seeking to improve relations, and/or a party of alchemists seeking to get their hands on some fabled dwarven ‘blasting spheres.’

But perhaps these bat farmers are looked down upon in the rest of dwarven society for their dirty job. And perhaps this creates a steady stream of adventurers into the surface world: disillusioned guano collectors figuring anything is an improvement over their current lot venture out to the nearest city seeking fortune and glory.

So next time you’re traversing underground tunnel complexes, give a little thought to the droppings that made it all possible. If you’re feeling especially generous, maybe bring a fresh bucket with you when you visit a dwarven fortress. I’m sure they’ll appreciate the gesture.

Check out our previous Underdark Ecology post here!