Where do forge-worms live outside of forges?

Question

Forge-worms are large bugs which flutter about the hearths of forges. They rely on the high temperatures of the forge to stay active and immediately fall into torpor when their body temperature falls below 1300°C

However forges are rather recent to the world, at least compared to the forge-worms. Hence, the forge-worms would need to have a natural habitat in which to dwell: This habitat must be hot enough to keep the worms alive, as well as having a source of energy and carbon by which the habitat's ecosystem can endure. Obviously it cannot originate from human intervention. Ideally the habitat should have an atmosphere similar to that of a forge's hearth

The world is pretty much Earth-like and has all types of natural features that occur on Earth (i.e. volcanos, fossil fuels). What natural habitat could these forge-worms dwell in?

Answer 1

Perhaps they evolved in a continuously burning natural gas field such as the Darvaza gas crater in Turkmenistan (image from linked Wikipedia page).

Then when gas was piped to nearby ovens they invaded through a burn-back incident.

Answer 2

They are surface-adapted bugs originally of cthonic origin

These critters are the descendants of organisms that live in molten lava. The dwarves were friendly to the originals, who kept returning home back into the melt. A few crawlies captured and bred in the lava plumes, each generation chosen for lower and lower temperatures, until something was born that was low-enough temperature to utilize.

Like all forms of domestication, the pets could interbreed with their wild versions, and sometimes break free and go feral. These are annoyances, untamed but able to sneak into the coal pile for a snack.

Answer 3

Forest fires

Forge-worms metamorphose through a complex life cycle. Only the adult stage requires extreme temperatures.

• Adult forge-worms emerge from their pupae in the inferno of a forest fire. They gather energy from the heat and help stoke and spread the flames. They mate and "forge" eggs in the inferno, and they enter torpor and die when the fire dies out.
• The eggs lie among the ashes, dormant, for decades, while a new forest grows. The freshly forged eggs are impenetrable; nothing can eat them. Leaves cover them and compost into dirt as the forest matures.
• After a decades-long internal timer, the eggs hatch into larvae. The larvae dig their way out of the dirt, then climb and burrow into the mature trees.
• Safe inside the trees, the larvae form pupae.
• The pupae remain in the trees for decades longer, perhaps even centuries, until finally a chance lightning strike sets the dried-out forest on fire.
• As the flames rage around them, the pupae hatch into adult forge-worms and the cycle begins anew.

The modern status of forge-worms as permanent residents of artificial forges is in some sense a perversion of nature. Forge-worms did not evolve to remain in the adult stage for very long. However, as long as there is enough heat energy to sustain them they won't die. They are actually quite helpful, because they instinctively make the forge burn more evenly and hotter, just as they would do in a natural forest fire.

Answer 4

A volcano is the obvious option, but a cool fantasy answer could be that they evolved around an incredibly long-burning coal-seam fire. It's not particularly realistic as they don't burn long enough to impact evolution so notably, but I think it would be interesting.

Answer 5

Natural nuclear reactors

Your planet has a much higher rate of meteor impacts and a lot of these have a lot of uranium in them. As such, it's quite common for high temperature natural nuclear reactors to form, which will last for a few tens of thousands of years.

The forge worms would rely on these, navigating to other meteors when their current one started to be exhausted. Some of them found forges, and went to live in those instead.

Answer 6

Erratic geysers

Their ancestors evolved to thrive in geysers, a wet environment that is subject to high pressures and temperatures. As volcanic activity slowed down in their region, they also became very drought tolerant. By the time humans came along and started making campfires these worms were already hardened to thrive under them. Campfires progressed to hearths, kilns, and forges, etc.

Answer 7

On Earth, tube worms have this issue. They only grow near hydrothermal events but hydrothermal events are short-lived in the geological scale and the worms and can't move away from them. They are considerably worse of than your fore-worms which can at least flutter about the hearth rather than being firmly planted to it.

The adult tube worms basically die where they stand but they release their gametes and the resulting larvae float around and those that land in suitable areas survive. Those that don't do not. There's nothing to say that the larvae can't have an exceptional form of torpor to increase their chances of survival.

Answer 8

Deep underground, but dug up because of the mining industry

Do you specifically need them to have been active and alive outside of forges and on (or near) the surface of the planet?

If not, then consider that they live underground, close to the planet's core. This is the most reliable source of this kind of heat, nothing on the planet's surface is going to be as consistently hot.

The worms sometimes get displaced closer to the surface due to things like volcanic activity, which "beaches them" away from the heat they need to survive. They go into a state of hibernation (which your mention of "torpor" could be referring to) and they get embedded in the nearby rock formations.

The rock is eventually dug up because of mining and subsequent smelting, and the heat of the forge brings the worms out of hibernation.

This would provide a reasonable natural habitat for them, given that the temperature limit you're setting is not reasonably found on the surface, plus it gives you the opportunity to make them pretty much only to be found in forges when you're focusing on the surface of the planet.