Monday, November 7, 2011

Big Enough To Fail

If you have a passing acquaintance with physics, and if you have the least knowledge of biological construction, you know already that giant creatures are flat out impossible, and that if they came into existence at the flick of a wand, they would collapse immediately under the weight of their own flesh.

There is a reason why insects or crustaceans are small, particularly on land.  It is the nature of the exoskeleton, in which the structural integrity of the creature comprises an outer shell enveloping the meaty goodness.  The bouyancy and pressurization of water will enable larger crustaceans to exist and retain their integrity, but the gentle reader will take note that one does not see four-pound lobsters clambering around, or 20-pound oysters or nestling upon dry land.

It is a simple mathematics problem.  If we consider a beetle, for example.  It is easy to find an example that might be one centimeter in length, and perhaps a total of one fifth of a cubic centimeter in size.  If we suppose that the beetles mass is equal to one fifth of a gram as well, we can compare the beetle's length to its mass as a ratio of 5:1.

If we increase double the length of the beetle, we increase the overall surface of that beetle's shell by the square of that length.  The larger beetle's skeleton is now four times larger than before.  However, the mass of the body is cubed, and is now eight times larger that it was before.  The larger beetle now weighs 1.6 grams.  The ratio to its length to mass has changed dramatically, and is now 5:4.

As we continue to double the size of the beetle, the mass increases exponentially while the body size of the beetle increases only arithmetically.  In other words, in very short order the beetle hits a size in which it cannot exist.  This is why the largest beetles in the world are only 15 centimeters long.

It is no different with creatures with internal structures, like ourselves.  If we double the height of a typical 200-lb. human, keeping all things in the same proportions, we find we have a giant that weighs 1,600 lbs ... with a far lesser percentage of that meat directly attached to the bones supporting the weight.  Even if we propose that the bones are larger, and that the tendons supporting the muscles and attaching them to the bones are larger, we still find ourselves with massive amounts of flesh and organs which will simply tear free from the structure of the skeleton, reducing our giant a mass of gooey muck.

Now, what I am not saying is that there should be no giant monsters in D&D.  Giants, along with huge crabs, ants the size of dogs, hornets the size of Volvos and so on are romantically fascinating things, and the game demands their existence.  Rather, I am proposing that there must be some other justification for the presence of these huge versions of smaller, natural creatures.  The obvious answer is magic.

We can suppose that there is some sort of 'magical integrity field' that enables the bones of a giant to support its massive size, or a rhinocerous beetle the size of a bus to scurry over the earth despite the comparison of its tiny legs to its necessary weight.  Perhaps it is some sort of net, with invisible nodes that extend to each critical support point in the monster's body, sustaining that point and keeping it free of the inexorable pull of gravity.  One might imagine having goggles that enable the viewer to see the magical 'tendons' extending throughout the giant creature's body.

Would this not, however, mean that if you chose to detect magic in the direction of a giant scorpion hiding in the bushes, the presence of the scorpion would be revealed?  Shouldn't this be true with all such creatures?  And if I should choose to dispel magic, shouldn't the body of the cyclops simply collapse, killing the creature?  And what other ways might there be to magically affect his integrity field, once we have argued for its existence.

Which creatures would, and would not, have this field?  A giant rat is no larger than a small dog.  Certainly the reason there are no pig-sized rats in the real world is not because pig-sized creatures can't exist due to the skeletal-to-body mass ratio.  So where does one draw the line, exactly.  Where does "very large bear" end and "impossibly large bear" begin?  When the bear is 1,500 lbs?  1,700 lbs?  Do I need my Guinness book of records to tell me when the creature starts being 'magical?'

We could posit that large creatures are 'magical' but that they're a different kind of magical that isn't affected by the existing canon of mage spells.  That seems like a bit of a hand wave to me, and in any case begs the question that if this magic integrity field exists, how come mages through the ages haven't researched to find spells that directly effect the field - never mind simply causing damage to the creatures, but rather simply obliterating the creature's ability to keep itself standing upon the earth's gravity well on its spindly little legs?

And while we're on the subject, perhaps the existence of giant creatures isn't regulated by a magical field?  What if there's some other reason?  I can't think of one and I'm open to suggestions.  I know some of you out there will be thinking "smaller gravity well," which has long been the staple of science fiction novels.  It won't work.  At some point the limit is still met, and mass will still fail to hang off the bone.  You've only changed the ratio limit.

The hand wave is the obvious solution.  But are we really looking for solutions, or are we looking for new ways to tap into inconsistences that have been hand-waved to the point where we've forgotten a hand wave was necessary?  Why shouldn't anti-giant creature magic be in some way be available?  "A wizard did it" only preposes that a wizard can undo it.


Eric said...

A mad god did it! She loves improbably large things, and transports their excess mass and inertia to her spot in the heavens, where she can admire them or dump them into a micro black hole or somesuch.

cyclopeatron said...

You don't really need magic to justify giant terrestrial monsters. What about dinosaurs like Argentinosaurus (~100 tons) or Amphiocelius (~120 tons if it actually existed)? Big carnivores like Spinosaurus even made it to 7-8 tons.

I think the main physiological bottleneck for giant animals is blood circulation. Paleontologists don't really know how the dinosaurs solved the problem, but giraffes (up to six meters tall) adapted through sky high blood pressure and various other mechanisms like a string of back flow-preventing valves in the major neck vein and super-tight leg skin(!).

Terrestrial arthropods are most likely limited physiologically by the structure of their diffusion-based gas exchange system. Also, huge insects or spiders would be crushed by their own weight while molting. Still, it's easy to imagine mundane adaptations to get around these challenges, like evolving true lungs, molting underwater, or partial molting.

What's my point? I'm just saying you probably don't necessarily need to invoke magic unless you get well over 100 tons. And that's assuming the physical characteristics of your game world are the same as for the real world. Assume changes to the atmosphere, gravity, animal gas exchange systems, etc. and your monsters could be really huge!

I think most biologists agree that the range of animals sizes we see today largely reflect ecological constraints as opposed to physiological constraints.

Oddbit said...

I'd go with Eric's approach, but with less insanity. All creatures were created by a god in theory. A god of magic would probably create or experiment with larger creatures. As guardians, as something to manage the higher creatures in the food chain or just because. I mean the platypus what more do you need?

You could follow the idea of science and logic down a very long train, but then you would end up with your world being very much like earth, as orcs and elves obviously would have never evolved for such and such reason.

Alexis said...

Or they could have evolved for a reason that is quite imaginative.

Why exactly is magic "interesting" and science "boring"...?

Closet theology?

Symeon Kokolas said...

The first step as mentioned above is physiological adaptation (such as better circulatory systems).

The next step I think is more advanced materials or what amounts to magical genetic manipulation. Tendons do not begin to approach the strength of spider silk, yet both are made of simple proteins. This could extend to exotic materials such as carbon nanotube exoskeletons or adamantite-reinforced bones. This also could include materials that are magically altered but are not themselves magical.

After that, active magical effects come into play.
The simplest is an enlargement spell. The spell itself does not mention the possibility of damage from overstressing the body, so one could assume that it functions as a scale factor on more than just size. The result is a giant creature that is stable only because physics is scaled in its vicinity (with the increased size as a byproduct). Dispelling this would result in a normal-sized creature.
More complex is active strengthening, where the physical structure of the creature is augmented to withstand the forces involved or a web of force holds some of the internal stress. Dispelling this would result in a mess. For creatures constrained by the vascular system, a network of short-range teleportation gates could distribute fluids and even act as filters.

Beyond exotic materials and active magic, deities would have the power to create whatever they want within the limits of their spheres of influence. This is what I get from Greek legends of the Titans; a time when enormous creatures were created and set against each other, eventually falling from favor as the gods became more focused on humanity and less tolerant of disastrous collateral damage.

This has a lot in common with an arms race, as I see it. If your world is relatively close to real timelines, then monstrosities created by the gods should be extremely rare or extinct. Actively-maintained monsters induce others with sufficient power to create their own juggernauts, but these creations seem too flashy to be justified in the long run. Passively maintained monsters are much easier to hide, much more likely to escape and much simpler to investigate as a wizard. These should be quite common. Anti-monster magic at the lowest level is simply damage output. As I see it, the point where dispel magic would be useful is also the point where either the effect to be dispelled is temporary or someone powerful has a personal interest in the monster's success (and may be able to counter or resist a simple dispelling).

Deciding which category should apply to which creature depends on the creature. Compare it to the largest of its type (insect, mammal, etc.) and use that as a guide. For instance, a dog-sized rat is no problem; a car-sized rat is conceivable (see bison); a house-sized rat is not reasonable without magic. A spider on the other hand probably needs magic at less than a foot of abdominal length while a crab might reach two or three feet.

Anonymous said...

Yes, I remember sitting though a similar physics lecture about why giants coldn't exist: because the bobdy weight would grow cubically, but the body structure's strength would only grow in a squared fashion. The point they were trying to make was more of a numeric or mathematical truth, but like many math models, they can fail in the real (or fantastic) worlds.

What I beleive is being forgetten here is about changes in bone density, ligament, and muscle itself. Larger animals not only had larger bones, but the densities of the bones were enough to handle the load.

And for (the usually long-necked) dinosaurs that actually did exist that well exceeded anything in the classic Monster Manual...they have surmised that they keep their blood pressure properly balanced by keeping their heads low and only lifted them for short durations if grabbing food off a high bough.

Alexis said...

Interestingly, I can quote my source for the biology above. It's a favorite argument of Isaac Asimov, whose biochemistry doctorate, honors and general genius trumps anyone here on the subject.

Asimov is also, by the way, the reason I call my readers 'gentle.'

Anonymous said...

Asimov is certainly more knowledgable than garden-variety scientists -- but if Asimov has more degrees and honors, he cannot be wrong? With life and things like economics (a higher order of the activity of life) and other topics that are the product of evolving and moving parts, even the best-and-brightests' imaginations tend to fall short of what is possible. To me, this is why such subjects are eterenally facinating, and why many find fantasy/RPGs and science fiction so captivating because it unlocks the mind. Just think of how many of our everyday devices/gadgets/inventions are themselves inspired by writers who think of ideas and concepts that "will be", and they are because someone plucks the idea from their writings. For example, Steve Jobs had even said several of his product ideas came from Star Trek, whatever you think of him or the TV series.

There is a lot of speculation about the types of species and lifeforms out in the universe, how they live, their shapes, sizes, forms, and other morphology, and even what is here on the earth surpasses the best scientists' imaginations.

The reality is that science fiction is probably closer to the truth of what is possible than what conventional science provides as possible.

Thanks for helping us with the opportunity to think about these topics! Fun!

Carl said...

Remember in Clash of the Titans (the original with Harryhousen's work) how the blood of the Medusa was spilled upon ground and the giant scorpions sprouted? That's an example of a magic creature that can't be unmagicked. The Gorgon was cursed by the gods! No mere mortal spell-caster can undo such powerful magic! Use your sword!

I handwaved the giant creatures as whims of the gods. Yes, they are technically magical. Can you "dispel" them? No. Unless you can dispel a god.

How I saw it was over the millenia, the gods and the nymphs and what-have-you get into little tiffs, disagreements and so forth. Sometimes things get cursed. Sometimes creatures are the result of a dare. Sometimes, as in the case of Hercules, a god fancies a mortal.

It's all handwavium, of course. Giant insects can't exist because they have sphericles and not lungs. They can't assimilate enough oxygen to support anything much larger than they are. They'd sufficate.


JDJarvis said...

the enlarge spell and bag of holding both look like likely results of exploring the magical field theory of giant creatures to me.

The giant creature could be just the hunk of the organism folks can see and interact with in regular space.

Alexis said...

Best argument yet, JD. Not only does it defeat the dispel magic, it defeats the detect magic as well. That centipede isn't actually 'giant' ... the reflection and the damage it does is the result of a bi-planar juxtaposition.

CrapEDM(Carpe Diem) said...

You could simply go with the idea that, since fantasy characters don't have the basic understandings of math and science that we do, they wouldn't think anything of the fact that these monsters have magical supports, and thus, wouldn't bother to study the new type of magic because they don't know it exists.

EOTB said...

The game works better if we don't put it under the microsope of modern science. A giant wasp is able to fly because the game needs it to, and it's a more visceral encounter than with 50 real-world-sized wasps.

Making the rules consistent with modern science is a rabbit hole without bottom.

Alexis said...

Just to bring you up to date, EOTB, science itself is a rabbit hole without a bottom. Doesn't dissuade scientists. Science is interesting.

I don't see why I should eschew something that's interesting. But point in fact, I'm not "making the rules consistent" with anything. I'm proposing NEW WAYS to think about old stuff.

Ah, I should have just not published this comment as unnecessary flat-earth thinking and technically off-topic.

Butch said...

And let's not even get into how dragons fly, or the mechanism of firebreathing...

Baron Opal said...

Actually, Peter Dickinson pursued that question in The Flight of Dragons (1979). It comes down to digestive acids producing hydrogen gas. This produces lift and a fiery breath, as well as describing a means for the corpse to disintegrate quickly after death.

It was a fun read and thought experiment.

Baron Opal said...

"The game works better if we don't put it under the microsope of modern science."

I disagree, ETOB. I find that magic works better when it has rational underpinnings. Thus the game is better, since magic is such a large part of it. The foundations can be flexible (Aristotlean vs Newtonian physics), but once that is fixed extrapolating from there adds a certain realism and fosters trust. When the DM says "no", the players understand that there is a reason beyond that of whim.

Some Guy You Might Think You Know said...

Sorry to resurrect and rehash an old post, but I think this is just one prong on the ... many pronged fork. Whatever mechanism for how you enable some impossible creature to exist, you should consider why that mechanism isn't more frequent. If giants have magical structural integrity, why don't more creatures have similar reinforcement for other reasons, say for armor. Wouldn't this decimate the ecology and lead to an evolutionary arms race? If the predominant predators are supported by magic that can be dispelled, how come the predominant prey animals couldn't dispel? Too many of the classic monsters have no ecology and exist solely to torment players. What do giant wasps eat, and where do they lay their eggs? Maybe there are giant caterpillars and moths too. Remember, insects collectively outweigh all other (land) animals and make up 95% of the species In the real world! And what about the plant-life?

Now, these statements are not meant to chastise, but to make you squirm with delight, because that's what your post did to me. How are your giants fashioned? Why are things the way they are? What lurks on the darkest jungles???

Charles Taylor (Charles Angus) said...

I don't know how big your conception of a giant wasp is, but in the Carboniferous era, there were dragonflies about two feet across. A wasp two feet long, therefore, seems totally plausible, and - to my mind - pretty terrifying.

10ft centipedes, maybe not so much.

But the existence of elephants (7-ton quadruped vertebrates), and tyrannosaurs (7-ton biped vertebrate) would indicate to me that you can have some pretty darn sizable humanoid giants, in the neighbourhood of 30ft without going beyond normal, our-world biology.

Their body shape would probably be somewhat different from ours, but recognizably humanoid.