I am looking for ways to get around the Square-Cube Law for the giants, dragons, and other large creatures of my fantasy setting. What are some realistic ways that it could be done?

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    $\begingroup$ Can you perhaps outline what's allowed to be bent or broken vs. what must be exact same as reality? Must your giants/dragons have emerged from darwinian evolution, or can they be designed/engineered? Can there be any deviations from real-world physics? If so, any guidelines for what is allowed? etc. $\endgroup$
    – Qami
    Jun 20 at 2:58
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    $\begingroup$ You can bribe me with pizza. Seriously now, large animals do that in some ways by increasing their internal area (mammalian lungs, many thin blood vessels). I may type a proper answer later. $\endgroup$ Jun 20 at 3:38
  • $\begingroup$ @Qami They were designed by a god, so their meat and bones can be different than a real creature's (such as having iron-like bones), but I want to avoid anything too unnatural. The natural magic aura of the world could handwave some difficulties caused by the Square-Cube Law, but not by that much. $\endgroup$ Jun 20 at 5:04
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    $\begingroup$ The square-cube law is not an obstacle, merely an observation on how the universe works. It relates material strength to structural strength. Make the material strength great enough (stronger bones, etc..) and the structural strength will allow larger creatures. Just bear in mind the other implications of the increased material strength. Like bulletproofness! There's a reason DragonBone is such a valuable material to make tools out of. The stuff must be both lighter and stronger than diamond!! $\endgroup$
    – PcMan
    Jun 20 at 6:47
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    $\begingroup$ @PcMan What kind of tools do you use to make tools from something stronger than diamond? And what kind of tools do you use to make those toolmaking tools ... $\endgroup$ Jun 21 at 6:44

On top of what Keith Morrison suggested in their answer, you can also use a different medium where to have the organism.

Look at the big cetaceans: their size would make it impossible for them to be land dwellers, however living in water and taking benefit from the increased buoyancy it gives with respect to air makes the trick of not overloading their structures.

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    $\begingroup$ Maybe the medium is "ether" or "mana". Some kind of pervasive field that permits magic to work. Wizards tap into it to throw fireballs, and step into it to teleport. Giants and dragons are partly supported by it, or its energy supercharges their cells or muscles. $\endgroup$ Jun 20 at 21:30
  • $\begingroup$ That is exactly what my setting has. Magic is supplied by the ether field of the world, and it could also support large creatures while having everything else work normally. $\endgroup$ Jun 20 at 21:51
  • $\begingroup$ Giant: "I'm gonna pound you!" Wizard: "Dispel Magic". Giant: Thud $\endgroup$ Jun 21 at 3:11
  • $\begingroup$ Lol. Dispel magic doesn't dispel the ether field, but funny suggestion. $\endgroup$ Jun 21 at 4:22
  • $\begingroup$ note that this works especially well in the case of dragons, which in an overwhelmingly large amount of fantasy settings, are creatures almost synonymous with magic (e.g. "heart of the dragon" being the magic center). this also would work with a setting "stronger" materials just contain more magic (and therefore are more resistant to magic and/or contain defensive magic). $\endgroup$
    – somebody
    Jun 21 at 5:04

It is a simple fact of physics: strength is proportional to cross section, mass proportional to volume (this is more important than the relation of surface area to volume: heat management has a lot more flexibility).

In order "get around" it by physical means (ie, not magic) you have to do one or both of the following things: different materials allowing greater strength than mundane analogues, or significantly reduced mass and thus overall density. That's pretty much it. You can futz around with some designs so your giants don't actually look like merely enlarged humans any more, as an example, but in the end it comes down to the material aspect. You want to do somethign bigger, you need to change the meat and bones.

  • $\begingroup$ What I have been thinking of is having iron-like bones and slightly stouter proportions for the giants, so that might work. $\endgroup$ Jun 20 at 5:06
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    $\begingroup$ @AshDrake049182 Iron is dense though and you haven't adjusted muscle strength to move the much heavier bones. Have you ever lifted a piece of iron the size of your femur? it's really really heavy, and that's lifting in a position where it doesn't have leverage which it would have if it was a limb. $\endgroup$
    – DKNguyen
    Jun 20 at 5:56
  • $\begingroup$ Interestingly enough cast iron has about 3 times the strength (~300MPa vs 115MPa) but also 3 times the density of bone (7.8g/cm³ vs 2g/cm³). You don’t really gain anything from switching to iron (unless you need its hardness). You’d need steel alloys which can achieve 700MPa and more to gain a real advantage. $\endgroup$
    – Michael
    Jun 20 at 16:34
  • $\begingroup$ @DKNguyen So I guess they will have a unique biometal alloy in their bones, which is both strong and light. Thanks for the help. $\endgroup$ Jun 20 at 18:10
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    $\begingroup$ @DKNguyen Well you could give them bigger muscles. Oh wait, that would make them heavier, so we'd need to make the bones thicker to support it. And then we'd need to give them thicker muscles again... $\endgroup$ Jun 21 at 6:49

Tubular bones and air sacks, a lot of cavities. That would not make the creature stronger, but scarier, it relies on the size to intimidate and push away possible challengers. It may also use the air to stay a long time under water.

  • $\begingroup$ Plus if they get hit hard and from below they could catch some serious air. Inflatable kaiju! $\endgroup$
    – Willk
    Jun 20 at 15:42

Low gravity

Lower gravity = less gravitational effect on things = things can be more massive.

High atmospheric / fluid pressure

If you have a dense enough atmosphere then you can have land whales. High pressure gives support to a creature's body.

Let animals use gravity emitting organs to cheat

More esoteric. What if very large animals had naturally evolved gravity/anti-gravity organs or graviton emitting / graviton reflecting cells?

What if dragons developed gravity-reflective scales covering their wings?

Mechanical evolution

So what if all life were nanite-assisted mechanical hybrids but no one knew? Like, what if alien nanites got into the evolutionary chain somehow billions of years ago and then it just evolved like that? The machines could be capable of constructing bones made from carbon nanotubes and similarly upgraded muscles / neurons / etc. All without anyone being any the wiser.


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