Piggybacking on this question: Can you simply scale up animals? how CAN we scale up living creatures to be giant sized? What would need to done to make truly giant animals (Dragons, Kong, Godzilla, etc.) possible? Land creatures, flying creatures, ocean creatures, included.

All the questions I've found pretty much say that it can't be done. Fine. But if we were to try to create said creature, what would we have to do?

As the previous question states its just not possible, I get that. So let's assume in this fictional universe there's some super science technology and that said technologies users are creating the creature from scratch or manipulating an existing creatures DNA to make the changes necessary. Don't just say "magic" though please.

For example: Bones and muscles made of denser but lighter material? Multiple hearts to get the blood pumping? Some cavity(s) in the body filled with a gas that makes the creature more buoyant? Brain with extra organ(s) that can send out greater/faster commands to the body?

Even changes to the creatures environments are welcomed if necessary, though I'd rather focus on the creature itself.

EDIT: Some more details- Earth gravity and environment, and no more than 24m / 80ft tall.

EDIT: I wanted to add these pics to give a kind of scale to the size of creatures that have existed IRL. That really big Brachiosaur in both pics must give us some ideas.

enter image description here

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EDIT: I believe my question is different from Is there a maximum size an ocean bound creature could grow to? in that the previous question is more specific to ocean bound creatures and I'm hoping to get answers that apply to any and all creatures that would be giant sized. Thanks.

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    $\begingroup$ @Kepotx I think he means scaling the wolf to like the size of a dragon, which causes problems as shown in the question linked $\endgroup$ Commented Apr 16, 2018 at 19:27
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    $\begingroup$ worldbuilding.stackexchange.com/questions/1360/… $\endgroup$
    – Tim B
    Commented Apr 16, 2018 at 19:42
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    $\begingroup$ "So let's assume in this fictional universe there's some super science technology and that said technologies users are creating the creature from scratch or manipulating an existing creatures DNA to make the changes necessary" - but this is magic... $\endgroup$
    – Aify
    Commented Apr 16, 2018 at 19:51
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    $\begingroup$ Possible duplicate of Is there a maximum size an ocean bound creature could grow to? $\endgroup$
    – Aify
    Commented Apr 16, 2018 at 19:52
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    $\begingroup$ Wait, we can't have giant creatures? The record-holding dinosaur is Argentinosaurus huinculensis. It's as long as a 12-story building and as tall as a 3-story building. Granted, it isn't furry (and I'd love to hear from an antropologist why there were no large furries back then), but it would seem that since Earth has already evolved large creatures, it's physiologically realistic to have them. Frankly, build your creature's physiology around the dinos and add aesthetics (like fur) to suit. $\endgroup$
    – JBH
    Commented Apr 16, 2018 at 21:59

6 Answers 6


The limits to the growth of an organism (most can be avoided by slowing down the metabolism and living in the water, but let's remain on dry land since it's more challenging) are - and I'm probably forgetting some:

  • structural: the organism no longer can support its weight, no longer can expand its lungs.
    • solution: replace the bones and the relevant muscles with artificial materials and externally powered cybermyomers (you will need a power source).
  • respiratory: the lung to body volume cannot increase past a certain point before the lungs become inefficient.
    • solution: you'd need to replace the lungs with a sort of continuous-flow turbine pipe (like the intestine, but way faster), solving also the problem of drying up; or equip the animal with externally powered oxygenators. Or you might supply it with independent "lung blisters" on the skin, which would also ensure redundancy.
  • circulatory: the heart cannot move the required volume of blood. Even if it could, the pressure would burst any organic vessel. And anyway, the blood can't contain enough oxygen to saturate both the nearest and the farthest cells along arterial radii.
    • solution: you need multiple hearts, wider vessels, a much faster circulation, and multiple separated circulatory systems, possibly each connected to one of the "lung blisters" above. Also thicker vessels and a pressure-compensating mechanism (from the top to bottom of Gypsy Danger there would be around three atmospheres of blood pressure differential).
  • sensorial/nervous: nerve signals don't travel fast enough.
    • solution: for a while, having multiple brain ganglia disseminated throughout the body will help. After that, you'll need to look into alternate solutions, like electric signals (not bioelectric ion waves) inside really insulated nerves - or artificial electric conductors. Possibly, a sort of organic optic fibers are possible by using very clear lymph in dedicated vessels, and retina-like, luciferin-rich ganglia as signal regenerators.

Then, such an organism would be too weak for itself. Simply banging into a tree or a rock would deliver enormous amounts of pressure, and therefore inflict untold amounts of damage.

Therefore, you also need to supply the organism with much tougher skin, or even armor (and somehow make that not interfere with air supply). You would have a segmented armor with the lungs beneath; the armor would continuously separate from the body for a suitable distance, with the scales sliding one against the other and leaving sufficient space for the air to flow inside. Then the armor would "deflate", forcing the air through the oxygen-absorbing channels immediately below, and you would end up with a wobbly, accordion-like rhino skin with "nostril"-like air ducts opening directly on it:

enter image description here

Having "even" squares inflate while "odd" squares deflate, and then inverting the air direction, could solve some of the drying-up problem and optimize air flux.

And finally you get to feeding the beast...

  • $\begingroup$ I like this answer. It coincides with a lot of ideas I had for it. As for feeding the beast it could eat others of its kind or other types of large beasts, and it wouldn't have to eat all the time. Just one big meal every once in a while. $\endgroup$
    – Len
    Commented Apr 17, 2018 at 18:14
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    $\begingroup$ it is worth noting sauropod dinosaurs basically have a one way breathing mechanism thanks to the air sac arrangement. $\endgroup$
    – John
    Commented Apr 17, 2018 at 21:17

We believe all living beings on Earth came from simple, microscopical organisms. The largest animals we have seen on Earth are the blue whale in water and Patagotitan on land:

enter image description here

You can make any animal just as big if you follow some guidelines:

  • You will need lungs. Simple oxygen diffusion will probably not do. Look at the chest cavity of those beasts.
  • Similarly, a very strong heart. The whale's can be as big as a Wolksvagen Beetle. As for the lizard, some scientists believe sauropods had evolved extra hearts along the neck. I don't think that hypothesis is popular these days, but you could think of that.
  • The weight of the creature must be sustained by water, or by a skeletal system that is comparable to a suspension bridge.
  • The creature will be fat, and will have to spend a considerable amount of its time eating. It would probably be a tree-eating herbivore or a filter feeder.
  • The brain will be comparably small compared to the rest of the body. That, compared with the inertia the beast will have, leaves little room for agility.
  • Its main defense against predators should be its sheer, obscene size.
  • Since it has to grow a lot, it will probably take decades to go from newborn to adult. More decades than a human in the very least.

And these are what I can think off the top of my head right now. Look for what is common between these creatures and the largest land dwellers we have these days (such as hippos and elephants).

A giant predator can exist in water (see Megalodon and sperm whales), but probably not on land.

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    $\begingroup$ As for giant predators in the sea, don't forget sperm whales, especially the ones that were allegedly much larger than the largest known to science. $\endgroup$ Commented Apr 17, 2018 at 12:37
  • $\begingroup$ @M.A.Golding thanks, I've added them to the post :) $\endgroup$ Commented Apr 17, 2018 at 12:49
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    $\begingroup$ What does brain size have to do with agility? I could possibly see making a case that increased travel distance of neuronal signals would reduce responsiveness and agility, but that isn't related to how big the brain is. $\endgroup$ Commented Apr 17, 2018 at 13:01
  • $\begingroup$ Higher oxygen, more co2, faster growing plants $\endgroup$
    – Pliny
    Commented Apr 17, 2018 at 13:18
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    $\begingroup$ @Len sometimes dino skeletons are found in the position they died. The most complete sauropod skeleton is that of a Camarasaurus. Even if other sauropods had different body shapes, they should not stray too much from that. $\endgroup$ Commented Apr 17, 2018 at 19:08

Giant photosynthetic jellyfish.

photosynthetic jellyfish https://en.wikipedia.org/wiki/Cassiopea_andromeda#/media/File:Cassiopeia_andromeda_(Upside-down_jellyfish).jpg

Jellyfish Body Plans Provide Allometric Advantages beyond Low Carbon Content

The fundamental differences in the body plans of jellyfish and other pelagic taxa appear to have a large influence on metabolic rates. Unlike most metazoans, the bodies of jellyfish comprise thin layers of ectodermal and endodermal tissue that line the external and internal surfaces of their bodies. The bulk of the body consists of the mesoglea, a robust extracellular matrix that comprises water, collagen fibres and salts [20] although in ctenophores, some muscle cells are also located in the mesoglea. The mesoglea provides structural support and has elastic properties that enable it to function as a hydrostatic skeleton, but because it contains few (scyphozoans and ctenophores) or no cells (hydrozoans), its metabolic demand is small [20]. Thus on a wet-weight basis, rates of respiration of jellyfish are much slower than those of other pelagic taxa but when scaled to carbon content, rates of respiration are similar to other metazoans.

Jellyfish scale up cheaply as regards energetics and materials. A jellyfish which did not need to move its body but could make reduced carbon via photosynthetic symbionts could get even bigger. Larger body = more surface area for photosynthesis = more food. Medium sized "photosynthetic" animals like this are common. I suspect the reason they do not get larger is that rough conditions stress large fragile bodies more, and also predation. Sidestepping these two issues, I could not figure out any theoretical upper limits on the size of an organism like this which is mostly water.

An animal like this is an animal, but has converged on the life strategy of a plant. Ocean plants can get very, very big.

  • $\begingroup$ very interesting and a totally different point of view. Thanks $\endgroup$
    – Len
    Commented Apr 17, 2018 at 18:15
  • $\begingroup$ Photosynthesis also runs into problems with the Square-Cube law, which tends to come up a lot whenever people talk about photosynthetic animals. $\endgroup$
    – Kaosubaloo
    Commented Apr 17, 2018 at 21:46
  • $\begingroup$ @Kaosubaloo: jellyfish have a workaround for the square cube law in that their interior body spaces can be largely metabolically inactive water. $\endgroup$
    – Willk
    Commented Apr 17, 2018 at 23:50
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    $\begingroup$ @Willk A Jellyfish could have an arbitrarily large volume, but it wouldn't matter for photosynthesis because photosynthesis requires surface area and not volume. Specifically, surface area is needed both for capturing the maximum possible amount of light and for respirating fuel and exhaust for the photosynthetic process. - Of course Jellyfish are weird. It is possible that they don't scale their energy use to size in the same way that other animals would, so this might be a moot point. You could also just make a very large, very flat jellyfish. $\endgroup$
    – Kaosubaloo
    Commented Apr 20, 2018 at 21:28

You can also explore the possibility of increased gravity. Creatures from a world with a high gravity would be either become smaller or larger. See this Reddit (https://www.reddit.com/r/worldbuilding/comments/4jpidj/how_does_stronger_gravity_affect_evolution/)

It really depends on how you want the outcome to be. If the stronger/higher gravity was not sudden then life would evolve to fit the environment and that would include denser bones, probably larger lungs and multiple hearts to support the body, muscle density becomes higher and would make creatures larger.

I've read a few books I think it was Pip and Flynx by Alan Dean Foster (don't quote me on this) where one of his species was large and strong due to living in a higher gravity world.


Decrease the size of the planet

On a smaller planet, you can have a bigger creature. Really, the largest problem with having a scaled up creature of any size is that it will get crushed under its own weight.

There are two problems with this:

  • If the planet is smaller, why does it have an atmosphere dense enough to support life?
  • The creatures wouldn't be able to survive on other planets.

Unfortunately, answering the first problem is more or less beyond me, short of having a heavy gas, or all life being water breathing (would the water need to be encased in some sort of shell to stop dissolved gas escaping?)

The second one limits the scope a little, too. It may be that large organisms will be able to survive fairly long in planets such as ours for relatively short periods.


**No There are limits. **

One of the simplest is the larger you get the stronger the limbs need to be, no matter what you make them from there is a point when they cannot support their own weight.

Other limits include the square cube law and gas/nutrient distribution, circulatory fluid column height limits, neural connection lag, heat dissipation, ect.

No they cannot just be scaled up

Additionally animal anatomy changes in noticable and predictable ways as they increase in size, this is especially well studied in dinosaurs, they cannot simply be scaled up. The square cube law lies at the heart of most of these changes and will hold true no matter what you make the organisms out of.


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