After thinking about it, I agree. Structurally possible but unlikely in an economic sense.
By analogy, one could ask if there is some alternate history where the world’s premier city is not New York but a large collection of rafts floating in the middle of the Atlantic Ocean where millions of people live and work. We may very well have the money & technology to build, populate, and maintain such a city – but what’s the point?
This is an important point - lets not forget that lots of animals are loaded with methane in their digestive tracts, and yet you don’t hear about those animals (humans included of course) spontaneously exploding
Lots of animals get around the seasons in one way or another - most insects have lifespans of less than 1 year - but the species survives because they lay eggs. Heck, think of mayflies live for a few hours or days before laying eggs and dying off. So our Beholders could hatch into some timer period that was abundant in food, live for a short bit, lay eggs, and die. By the way - have you ever seen ponds during mayfly season? They’re there by the tens of thousands. That would be a perfect place for our insectivore beholders to be born, eat some mayflies, and die.
Just a nitpick - Beholders aren’t balloon animals. They float by levitation (Cite: 2nd Ed. Monstrous Manual, page 21). I doubt *such *a creature could evolve naturally.
Don’t you need to pierce a body’s stomach to keep it from exploding if you are doing a primitive cremation?
ISTR reading that, but I could be mad.
A creature could, however, evolve such that no magic functions in a 100-foot-long cone in front of it :).
I immediately thought about detached floating eyes, but that’s the Quasta, from Dragonstar. The beholders are all connected, aren’t they?
Take a look for yourself:
BEHOLD!
This changed in third edition, I believe. They do not use magic to levitate; they are naturally buoyant.
Food would be a problem. So it seems to me the only way this could work would be if the “floater” incarnation were but one stage of a multi-stage life cycle. (A stage during which their nourishment needs would be limited or eliminated.)
Wind is a problem, because it means most floaters would wind up out over the oceans, where there would be no food, and no place to land.
Isn’t that a little bit like the community that made do by taking in each other’s washing? If the beholders create beholder spores, which they then eat, they’re not gaining any energy. The only energy that gets into the sysem is when the spores are lucky enough to land on something edible.
To be naturally bouyant, a 1m3 Beholder would weigh 1200g.
Let’s make some assumptions:
the Beholder is a cube (to make the math a little easier and I don’t think it afffects the outcome too much)
the Beholder’s flesh has the same density as water (again, close enough for an approximation)
Mr Floater is filled with hard vacuum, not gas.
The surface area is 6m2
Each 1m2 side weighs 200g
If my math is correct, that gives an average skin thickness of 0.2mm for the Eye Tyrant.
It’s pretty hard to imagine a three foot wide creature cramming a brain, a digestive system and a huge freakin’ eyeball into a film about as thick as a human hair.
Perhaps they’re born with fishing poles?
That’s why there are a lot of spores. And why they start small, so they take a minimum amount of energy to make.
But…where do they keep the gas? I mean, those suckers are almost all mouth and eyeballs.
Their eyes hold the gas. That’s the beauty of it. And, as you know, beauty is in the eye of the beholder.
Let me try that calculation…
Larger is usually easier for flying, so I’ll assume a 2-meter diameter spherical balloon organism. That gives a volume of 2.3 m[sup]3[/sup]. Assuming STP, mass of displaced air is about 3.0 kg. Density of hydrogen is roughly 1/30 of air, so buoyancy is about 28 N.
Spider silk is on the order of 5 microns thickness. Even if it needs to be woven and connected with impermeable membrane, 20 micron thickness would seem plausible. Assuming density of 1 g/cm[sup]3[/sup], the balloon envelope weighs 2.5 N, or about 0.5 pounds. That leaves over 25N (5.6 lb) for the gas-generating organs, fins, brain, etc.
Just to check whether strength of organic materials is a limiting factor: spider silk has a tensile strength of 1.3 GPa, which means only 0.02 mm[sup]2[/sup] is needed to support 28 N. That’s 20 micron * 1 mm, so that shouldn’t be a problem.
I’ve already taken a patent out on it.
Ouch!
I’ve never gotten into the later versions, so I don’t know if this was actually retconned in 3rd ed. But in my native 1st ed. AD&D, beholders levitated by magic, because they just wouldn’t work otherwise.
However there was a D&D gasbag that floated by standard bouyancy known as the Gas Spore. They had evolved to mimic beholder’s outward appearance, though the eyes were false. Gas spores were actually a sort of fungus, and thus had little need for actual sense organs. They tended to explode when attacked, and used this as a means to spread their substance all over the place. Any fleshy shrapnel that landed on a food source would grow one or more new gas spores. Looking like a beholder helped ensure that only larger ‘food sources’ would be brave/stupid enough to cause the explosion.
So the spore wasn’t actually from a feeding part of the organism’s life-cycle. That lessens some of the ecology problems.
The major advantage of such an evolutionary route is that if a creature flys along even ten meters in the air, it’s vitually taken itself out of the predation zone. (“Hey, look - lions. That’s right, try and jump up and catch me. Like that’s gonna happen. Well, I’m just going to piss on your head and then slowly drift away now. Later, lions.”) There would perhaps be some threat from hawks and eagles and such but I can easily see ways a creature could evolve defenses against them.
I’m pretty sure I radiate a field that negates magic in a 100’ radius. There doesn’t seem to be metabolic cost for this ability.