I was recently thinking about Dragons, and got thinking about what they would have looked like in prehistory. Dragons were able to survive through the times due to two. main factors:

  1. Their Size. Dragons are large in my world and can live for over 3000 years. I have found this image and it gives you the basic idea of size. I'd say dragons can be smaller than this, and this is about the biggest any could get. They're size does vary, and like I said, this is about the biggest they could get (so not the most accurate.) enter image description here

This size gave them an advantage as apex predators, resulting in them being difficult to kill.

  1. Their Strength This gave them power to do almost whatever they wanted, and again helped them rise to the top of the food chain. Their traits being: Claws, Fire breathing, Speed, intelligence, etc.

So with these two things in mind, them being huge and powerful, I began researching prehistoric things, and noticed a pattern of them being bigger or smaller. So, from there I began looking to see if winged things were bigger or smaller, to which I was not successful at all. I did find why things were bigger, and some factors were higher oxygen levels, More space (bigger landmasses.) And, my world was also one or two landmasses during most of prehistory. Also, Dragons were there for most of prehistory, from the beginning to present. This is as far as my research went.

Some other things on Dragons. They are adaptable, and can live in almost nay environment. They are scaled and cold blooded. They have two sets of teeth (this is the average, some have more or less. Don't even know if this is helpful.

That's about it. Thanks,

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    $\begingroup$ If you don't own the image you should not post it here, unless you have the authorization of the author $\endgroup$ – L.Dutch May 4 at 16:35
  • $\begingroup$ I believe the image is public domain $\endgroup$ – Destructive Wolf May 4 at 16:37
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    $\begingroup$ This is entirely dependent on particulars of environment, evolutionary history, and ecological niche, Also since the default size is already too large for real biology this becomes based on your handwavium. I am voting to close because this is pure opinion. $\endgroup$ – John May 4 at 17:34
  • $\begingroup$ When originally published on the web in 2015, it is categorically stated that this is not that person's property, again, please state where you got it and under what license, else delete the link. $\endgroup$ – A Rogue Ant. May 4 at 20:58
  • $\begingroup$ @ARogueAnt. He's not using that specific image. This is just a silhouette of a render done by the Hobbit film crew. (In fact, the image you linked appears to have been made by modifying that same silhouette and/or render.) Since he's not claiming the art as his own, or stealing from a smaller cretaor, or making money off this post, I'm pretty sure this is covered by the fair use policy, which allows people to use copyrighted images in certain contexts. $\endgroup$ – Globin347 May 4 at 22:41

You should ask yourself what are your dragons eating. I point to it, as you mention it is an apex predator (rather than fully magical creature that may need no food)). The beast you pictured would not eat sheep and occasional virgin. Mammoths would be enough for a snack, but multiple will be necessary per day. You would need comparable megafauna in big numbers to feed your dragons.

It is also bigger than any animal living on land (or maybe even biggest single animal, period), so I'd say it is safer to assume that it's ancestors were smaller, as bigger would be increasingly improbable.

You should also consider dropping the the cold-blooded trait, it would not allow them to live in most environments including dragon favorite mountaintops. There is a reason all big lizards and crocodiles live in hot or very hot environments.


Well this can be seen as 2 ways, the broad one and the less broad one:

1- at no point in history have your dragons ever obeyed biology or physics.

This scenario is the easiest to answer: unknown. If your dragons have never obeyed biology or physics (especially regarding the square cube law), then for all we know prehistoric dragons could've been as small as a bumblebee bat to as large as the Everest. Nothing has ever limited their growth and thus its impossible to determine and the option is up to you.

2-at some point in history they were still bound by the natural laws of our universe

Disclaimer: from this point on, I'll assume your modern dragons have a body plan more similar to that of a wyvern (4 limbs total, with 2 front limbs turned into wings), since you used the model of Smaug from the Hobbit trilogy of movies.

This is scenario seems to be the one you're trying to follow since you went as far as to research about prehistoric animals to see if there was a pattern, and normally there still wouldn't be a clear pattern, except for a key trait: flight

Flight is an ability that has truly evolved only about 4 times, as far as we're aware, 3 of them occurring in vertebrates. Why is it important? Because of 2 little things regarding its evolution in these groups specifically:

  • flight is no walk on the beach, while even animals highly adapted for living on land can still swim (see horses and ostriches), air is a lot less denser, and even the act of falling with style (aka gliding) usually requires a fair number of adaptations.

  • the bigger you are, the harder it is to fly.

Couple these 2 bits of information with the data we have from these 3 groups of vertebrates, more specifically pterosaurs, and we have a pretty good idea of why exactly they were more lively to have started out smaller than bigger:

1- essentially all examples of early flying vertebrates he know of were not that big. Certainly they weren't something absurdly small, but one thing we know is that they didn't include anything the size of dakotaraptor. This is easily explainable by the fact, according to the square cube law, means not only that you're lighter, but that you're stronger in proportion to an animal twice as large. This mix of reduced weight and proportionally stronger muscles means it'll be a lot easier for a smaller animal to ever begin exploring the niche of flying predator that it would be for something much larger.

2- once you got them wings developed, keeping them functional as you scale up becomes harder. For this bit, we'll look at the best example we have: the azhdarchid family. This group of pterosaurs is the one that houses not only the biggest pterosaurs to ever live, but the biggest animals that ever took it to the skies (on its own, at least). When looking at these pterosaurs and their adaptations, one thing becomes clearly obvious: they were extremely adapted for flight, from the lack of tails to incredibly hollow bones, these creatures were adapted for flight to an extreme, and chances are that these adaptations could only really come from a smaller animal that needed them to take place in order to grow without sacrificing the ability to fly.

And don't think these extreme adaptations meant they couldn't be proper predators, since examples of particularly robust azhdarchids like hatzegopteryx, which is a species of pterosaurs that most likely ruled Hatzeg Island as the biggest predators around, exploiting the insular dwarfism and how it resulted in an environment filled with smaller dinosaurs it could likely hunt.

So tl;dr: if your dragons have never respect the square cube law or any other principle that'd allow them to be larger, heavier and more powerful than any sauropod without giving up on flight, we can't be sure, simply because no laws are binding how big they could've been before magically deciding they wanted to be able to fly (and yes I'm assuming flight necessarily came after unless everything in your planet could fly at some point). BUT if their ancestors were indeed bound by natural laws at some point, they would have most likely started out as smaller aerial predators, later deciding they'd let no laws bind them and challenge all logic to become their current size and outlive any turtle by millenia.

Also, unless we have some seriously big megafauna rich in nutrients and energy your dragons will have problems with getting their daily requirements to live. Being that absurdly big and powerful while still being able to fly and all of that without sacrificing a powerful brain would probably mean they'd make a hummingbird's normal state of being at the edge of survival (they can starve in about 5 hours at their normal metabolic rate if they go that long without eating) look like it's not that bad.

Edit on something I forgot to mention: "being cold blooded" and "can live in almost any environment" are pretty much mutually exclusive, especially if you also want them to be flying vertebrates. While their size would normally make dispersing heat a big problem, when we look at nature we can see that:

1- not flying vertebrate on earth was ever truly cold blooded. Even pterosaurs were at least in the path towards endothermy, especially since flight requires a constantly high metabolism more easily found in warm blooded animals.

2-cold blooded animals, being highly dependent on environmental heat, don't really do well in polar/very cold regions. If you want dragons that can live in Antarctica or in mountain tops, you'll need them to be at least mesotherms (we suspect not even sauropods were truly cold blooded given how fast some of them grew up).


First of all, for a being living 3000 years the prehistoric times would be their grandparents' times: not a long time to ensure any adaptation to a changed environment and this already can bring some problems, because climate for example can change in a comparable time scale with their lifetime.

But putting that aside, there is no a priori reason for them being necessarily smaller or necessarily bigger: it's again depending on the adaptation to the environment. It can go both ways.

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    $\begingroup$ Actually, your wrong, it would be more like their great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great great grandparents. $\endgroup$ – Destructive Wolf May 4 at 17:58
  • $\begingroup$ It would be at least 40 million years ago $\endgroup$ – Destructive Wolf May 4 at 18:00
  • $\begingroup$ @DestructiveWolf Not necessarily. Dragons are generally portrayed as nigh-immortal. $\endgroup$ – The Daleks May 4 at 18:30
  • $\begingroup$ My Dragons are not immortal $\endgroup$ – Destructive Wolf May 4 at 20:02

Questions about dragons get asked every now and then. First, about oxygen levels:

To my understanding, that only applies to the carboniferous, the age of giant insects and superforests. The dinosaurs lived with a similar oxygen level to what we have today.

Also, Flying animals can only get so big because the power-to-weight ratio of muscle becomes less favorable with size. This is the square cube law. This video provides a quick overview.

In any case, flying animals are hit very hard by the square cube law, so their size is especially restricted. The giant Azhdarchid pterosaurs from the cretaceous were probably about the limit, and they had to make some big sacrifices to get into the air. Their bodies are proportionally small, their tails are reduced, and their hind legs are very weak.

my take on dragon size is that, without magic or some other force that boosts the amount of downward force the animal can produce in flight, the absolute largest you could probably get is the size of a horse, and then the dragon would probably have a relatively small body and short tail to reduce weight.

I will say, though, that contrary to some older hypothesis, I don't think the dragon necessarily needs to loose it's teeth to become lighter. Before the end cretaceous meteor impact, there were lots of successful toothy birds; beaked birds survived because of their diet, not their weight.


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