Ways for Monsters to See in the Dark

[ericthered]

Originally Posted by Anthony

It's worth remembering that any situation in which you have substantial amounts of subterranean life implies there's an energy source down there that can support that life, and the life down there has a way of tapping into that energy source, which in turn generally means it also has the ability to detect that energy. That could in principle only be the producer organisms (subterranean equivalent of photosynthesis) but it's likely there'd be an evolutionary advantage to creatures further down the food chain also being able to detect that energy. Typically that would be magic, though other sources are possible enough.

Originally Posted by Apollonian

Another way, similar to IR, might be to say that the creature can detect very fine variations in the local mana field. Setting-dependent, very obviously, but if different substances (let alone different living beings) alter the way mana flows and pools through them, something's probably going to take advantage of that for sensory purposes. And spellcasting will really stand out for them.

Yeah, there's a planned ecology based on "mana blooms", where a large amount of mana shows up in a location for a while... not sure which direction it should come from. Being able to sense these is a high priority. But it also means that ambient mana to see by only shows up some of the time... though an animal that lives as a dormant egg until the bloom shows up wouldn't need any other senses.


It occurs to me that casting magic in this setting might attract predators... which is an awesome idea. Gives new purpose to wandering monster rolls.

Originally Posted by Anthony

The big problem with targeting via ground vibration is that common ground vibration has a quite large wavelength (likely multiple meters), which isn't really usable for localization unless you have extremely widely spaced sensors or the distance is very short.

So its good for long distance but not for targeting... I wonder how it works for navigating tunnels.

Originally Posted by Farmer

Yep. If I were creating a creature for a game, I'd probably make them a little like a submarine. Passive listening for long range and then active for short range accuracy (i.e. emit a high frequency vibration that's like echolocation but transmits through the surfaces. Their attack modes would need to reflect this (large swinging appendages or barreling charges or sticky excretions or poisonous or toxic emissions and so on. Maybe even a large enough vibration to act as a local tremor to knock foe down.

Originally Posted by Willy

You mean like bats, their echolocation ist precise enough for any cave on this planet, maybe a parabolic hearing for passive detection combined with the bats system, Have you considered sound as a weapon? Sperm whales use it active to stun their prey.

I haven't looked at using sound and tremors as a weapon... that could be quite a bit of "fun". Thanks for pointing me that way. would armor provide any protection against a sonic attack like a whale is theorized to use?

A classic mentioned in many SF novels playing in caves are predators using a bright flash to stun or overwhelm the senses of prey. Or you use something like the black sea devil https://en.wikipedia.org/wiki/Black_seadevil to lure the prey to you.

Looking at real life bioluminence is interesting. I see a few different options. Sometimes its a mating "call", a means of long distance communication. Sometimes its meant to startle or scare-off a predator, or to attract its predators. Sometimes its to attract food, though that only works if other legitimate reasons for bioluminence. I did read that some mushrooms glow to attract seed spreaders, and that could work in an underground ecology, especially with a fruit-like "reward" associated.


However, bioluminence is a big deal in the deep ocean because while there is no light, there is nothing to block the light, so it carries quite far. Tunnels are a little different.


I was thinking about coming up with an excuse for my mushrooms/mana-bloom corals/ other manavores to glow, and had the thought that the most efficient way to consume mana involves releasing light: it justifies some colorful imagery often associated with magic and makes the mana-blooms into islands of light.

[Varyon]

Originally Posted by ericthered

Yeah, there's a planned ecology based on "mana blooms", where a large amount of mana shows up in a location for a while... not sure which direction it should come from. Being able to sense these is a high priority. But it also means that ambient mana to see by only shows up some of the time... though an animal that lives as a dormant egg until the bloom shows up wouldn't need any other senses.

Being mana, it might just... show up. Some area of the tunnel is basically manaless, then in short order the mana level there just starts to ramp up for the "bloom."

Originally Posted by ericthered

It occurs to me that casting magic in this setting might attract predators... which is an awesome idea. Gives new purpose to wandering monster rolls.

Magic items could also be a huge lure to manavores. Assuming they can consume the mana within such items, that would mean first that delvers would be unlikely to use magic items (unless the magic can be obscured), and secondly that magic items would absolutely not be part of the treasure found in such tunnels, as they'd have already had all the mana sucked out of them. So, there needs to be other goods for delvers to acquire by journeying into the Underdark - organs harvested from freshly-slain manavores might be rather useful as materials (for spells, potions, magic items, anti-magic items, etc), there may be precious gems and metals in abundance, or perhaps the real "treasure" is simply being able to trade with the sapient Underdark natives (who may well have magic items, the purchase of which may make getting back to the surface unscathed... interesting).

Originally Posted by ericthered

Looking at real life bioluminence is interesting. I see a few different options. Sometimes its a mating "call", a means of long distance communication. Sometimes its meant to startle or scare-off a predator, or to attract its predators. Sometimes its to attract food, though that only works if other legitimate reasons for bioluminence. I did read that some mushrooms glow to attract seed spreaders, and that could work in an underground ecology, especially with a fruit-like "reward" associated.

Note you may well have monsters who emit mana in a similar manner, particularly if mana-sense is more reliable than vision in the winding tunnels.

Originally Posted by ericthered

I was thinking about coming up with an excuse for my mushrooms/mana-bloom corals/ other manavores to glow, and had the thought that the most efficient way to consume mana involves releasing light: it justifies some colorful imagery often associated with magic and makes the mana-blooms into islands of light.

I rather like this idea. Note it also implies magic items would be obvious by their glow - at least in the dark (you may want to consider the mana-glow being relatively weak, such that normal levels of light wash it out; this will also mean those without Night Vision will still be penalized, as the mana-glow isn't enough to see by without issue).

[Farmer]

Originally Posted by ericthered

I haven't looked at using sound and tremors as a weapon... that could be quite a bit of "fun". Thanks for pointing me that way. would armor provide any protection against a sonic attack like a whale is theorized to use?

I guess it depends on whether it's narrow "beam" or a large area. Ultra-tech has sonic weapons - pp124-126. They have different sorts of damage (HT based and HP based) with various effects. Worth having a look at and maybe modelling something on items that exist. Armour could help with narrow beams if it can disperse or reflect part of the energy, and maybe even for larger areas of effect if it can absorb or block.

[Anthony]

Originally Posted by ericthered

I haven't looked at using sound and tremors as a weapon... that could be quite a bit of "fun". Thanks for pointing me that way. would armor provide any protection against a sonic attack like a whale is theorized to use?

Hard armor can reflect shock waves, potentially either reducing or enhancing their effects, but actual thickness doesn't play a lot of role so the effects wouldn't depend on DR. Soft armor can absorb or break up shock waves, which is more reliably useful, but it's not really possible to be all that effective without removing the ability to hear.

In general it will be very hard to have effective atmospheric sonic weapons, though; atmospheric shock waves just aren't anywhere near as dangerous as underwater shock waves. As for tremors, the major effect will be causing tunnels to collapse, which while effective in the short term is pretty inconvenient in the mid to long term, so I doubt it would be a favored choice.

[Inky]

Regarding glass lenses, the lenses in trilobites' eyes were made of transparent calcite. I'm not sure off-hand whether calcite refracts infra-red or not.

[whswhs]

Originally Posted by Inky

Regarding glass lenses, the lenses in trilobites' eyes were made of transparent calcite. I'm not sure off-hand whether calcite refracts infra-red or not.

Pretty much every material substance has an index of refraction greater than one. I believe this is because light travels more slowly through any material medium than through vacuum; it's differences in light speed that give rise to refraction. I don't see that this would be any different for near infrared than for visible light.

[Anthony]

The main concern is opaqueness, not refraction -- other than a few esoteric metamaterials, everything has an index of refraction greater than one.

[ericthered]

As a related note, what would a written language for a civilization that uses echolocation or touch to read look like? Braille? What would a touch-based language other than braille look like?

[Willy]

Originally Posted by ericthered

As a related note, what would a written language for a civilization that uses echolocation or touch to read look like? Braille? What would a touch-based language other than braille look like?

Touch based can be every actual and dead language, as long as it is engraved or raised, maybe at least a bit roughened so your fingers can feel them. The good old cunaiform script is good readable for a blind person. Braille is just easier because it was purpose made for the job. Better the letters or words distinct to the touch the better you can read it.

[whswhs]

James Cambias has a touch-based language in his first novel, A Darkling Sea. As I recall, it's based on tracing spaced knots in a length of cord.