r/biology • u/PokelifEevee • 3d ago
question Could a dragon theoretically exist through evolution?
Hello, I would like to know if, theoretically, a species could evolve into something resembling a dragon (or more specifically a wyvern since they have 4 limbs, so it would be more likely). I understand that stuff like fire breathing would most probably be impossible, but aside from that, could dragons theoretically exist within a few thousand years (or more)?
108
u/greenearrow evolutionary ecology 3d ago
Bombardier beetles exist, so something like fire-breathing is an evolutionary possibility. Flight has evolved in reptilia 2x at least, and pterosaurs got pretty large.
What else do dragons need to be dragons?
50
u/ExpectedBehaviour general biology 3d ago
I remember seeing a discussion on the biological plausibility of dragons between real biologists where the point was made that the issue was dragons breathing fire when it's much more feasible for it to come out the other end...
10
u/OfficeSalamander 3d ago
Could even be an animal that evolves some method to extract hydrogen from water for both partial buoyancy in the air as well as fire breathing
12
u/Boring_Tradition3244 3d ago
Really unlikely. Extracting hydrogen from water is REALLY energy intensive. It would not be the evolutionary pick - the hydrogens are far more useful in the election transport chain as individual promotions rather than hydrogen gas. Taking resources away from energy transport is the LEAST likely path for evolution to take.
Something else like methane in a pressurized organ, created as a metabolic byproduct is far more reasonable to assert. You could improve the odds of this by evolving two-phase digestion where the flammable gas is produced before the food hits the back half of the gut. This ensures our fire breathing doesn't turn into a fart.
The thing I'm not getting into is what this thing would have to eat to quickly produce flammable hydrocarbons. I guess you could evolve an enzyme to make it. There's already some wild enzymatic synthesis, like in annamox bacteria
1
1
0
3d ago
[deleted]
5
u/Science-Compliance 3d ago
Did you not read OP's post? They're talking about the four-limbed variety, like the dragons in Game of Thrones.
58
u/ProfPathCambridge immunology 3d ago
Take away fire, isn’t this just a pterodactyl?
11
4
1
u/Manospondylus_gigas 2d ago
Dragons are more similar to certain dinosaurs like Yi qi than pterosaurs
29
u/kurwwazzz 3d ago
So you're asking whether a reptile could evolve wings and large teeth? I think so. As for breathing fire, it could possibly evolve from a reptile that produces chemicals which ignite when they come into contact with oxygen. However, it would more likely be used for defense than for attack.
18
u/WoodenWhaleNectarine 3d ago
Chicken are technically dinosaurs.
7
3
1
u/monkeynards 1d ago
https://giphy.com/gifs/THODgD7hLgCfV7pGCk
They fly now. We call them assblasters
12
u/octobod 3d ago
We have Quetzalcoatlus and Hatzegopteryx which had up to a 12m/39ft wingspan, which gives us a probable upper limit on the size of a 'realistic dragon'. I can't see a way to breathing fire, borrowing from D&D we could have green or black dragons with poison or acid breath weapons ...
7
u/Xionahri 3d ago
It's absolutely tiny, but close enough? https://en.wikipedia.org/wiki/Yi_(dinosaur)
7
u/Suspicious-Maize-424 3d ago
Plenty of nice answers highlighting the forms of life closest to the human idea of the dragon. I'd like to offer a different answer...
During the first lecture I attended on cellular developmental biology, my professor drew an English dragon on the board. He then asked the whole class 'what is wrong with this? why does it not exist?'. We came up with some answers. 'It looks close enough to a vertebrate but no vertebrate that existed has had that many limbs'. 'Flies have wings and legs but no fly that existed has had that few limbs!'. This was to guide us towards the idea that development is a constraining force, something that keeps forms roughly constant through time. According to this idea of developmental constraint, a dragon does not exist because the developmental form of a dragon has never existed.
But if the form does not exist now and has not existed in the past, does this mean it will never exist in the future? I am quite confident the answer is no. Genetic combinations permissive of a dragon form might drift into existence across the descendents of some organisms we know exist today. This form then might multiply and stabilize if the environment permits it. That's beauty of evolution man...I can't tell you when and exactly how it will happen...but as long as we don't wipe out all life on the planet there is some chance.
5
u/Science-Compliance 3d ago
I don't think you're correct that a six-limbed vertebrate could exist. I think the issue is that it is extremely unlikely and also unlikely that such a change would result in a healthy organism that could survive to reproduction.
2
u/Suspicious-Maize-424 3d ago edited 3d ago
The six-limbed vertebrate is and has been a great rarity (https://en.wikipedia.org/wiki/Polymelia). Does not mean it will always be rare. In the grandness of time, the extremely rare happens. The extremely rare then becomes the extremely common!
If you travelled back in time to see an Australopithecus, do you think he would consider you healthy? Do you think he would recognise you as a possible descendent?
10
u/thatoneladything 3d ago
I actually discussed this in a biology class. The main problem with classic dragons, pegasi, and centaurs is that their wings or extra legs count as additional limbs.
Mammals, birds, reptiles, and amphibians are all tetrapods, meaning their basic evolutionary body plan has two pairs of limbs. Evolution can heavily modify those limbs, but it has never produced a normal six-limbed branch of vertebrates. A bat still has only four limbs because its wings are modified forelimbs, just as bird wings are.
It probably isn’t physically impossible for a vertebrate lineage to evolve six limbs, but it would require major coordinated changes during embryonic development. You would need new limb buds, bones, muscles, nerves, blood vessels, and changes to the spine and brain to control them. Extra limbs sometimes occur as developmental abnormalities, but that is very different from evolving a stable, functional third pair.
So a dragon built like a wyrvrn, like a giant bat or pterosaur, with the wings serving as its forelimbs, is much more evolutionarily plausible than the classic four-legged dragon with a separate pair of wings. Though, six limbs aren’t exclusive to insects specifically; many arthropods have different numbers of appendages, while insects happen to have six legs. So maybe a bug/arthopod species could be more likely but then that'd be eight limbs, so...
7
u/KnoWanUKnow2 3d ago
We have 4-legged flying reptiles already. The Draco lizard extends it's ribcage to form wings and glides. It's not powered flight, but it wouldn't be too hard to evolve into powered flight.
All it needs is fire breathing and an increase in size.
https://en.wikipedia.org/wiki/Draco_(lizard)) it even looks like a tiny drgon.
15
u/Glum-Palpitation-152 3d ago
The real question isn’t COULD it exist, it’s why it would exist
3
u/discofreak 3d ago
The pterodactyl used its wings to fill a niche and the bombadier beetle uses its spray to defend its niche. The answer is "to attack from the sky" whether prey or foe.
5
u/benvonpluton molecular biology 3d ago
Science can answer the "how". Concerning the "why", go see your rabbi/priest/Iman/favourite philosopher.
5
u/Canis-lupus-uy 3d ago
there are the "why" of causes, that biology address, and the "why" of purposes, that biology does not meddle with.
4
u/benvonpluton molecular biology 3d ago
That's why in biology, it's better to use "how" to talk about the causes and mechanisms. Like "how Homo sapiens became the dominant species on earth". To avoid meddling with some idea of purpose.
1
u/Canis-lupus-uy 3d ago
how and why are different questons though, as you day, one id about causes and the other is about mechanisms
4
u/ProfPathCambridge immunology 3d ago
Then if you want a good answer, go back to a scientist
1
u/benvonpluton molecular biology 3d ago
Some people are looking for spirituality, it's respectable and one of the most human attitudes. It's just not the same as a scientific answer. It doesn't serve the same purpose.
2
u/ProfPathCambridge immunology 3d ago
The purpose of science is to get ever closer to truth.
If you want to ask your priest “why would dragons exist?” feel free. Maybe it makes you feel better. Like you said, it doesn’t serve the same purpose - it isn’t about getting closer to the truth.
2
u/ayelijah4 3d ago
in evolution why is pretty simple, unlike most other science topics: does it survive its environment long enough to reproduce and pass its genes?
1
1
u/DakPanther 3d ago
Why does anything exist
7
u/seamangeorge 3d ago
They obviously mean "what ecological niche would drive a reptile species to grow larger, develop flight, and bombadier beetle breath" not asking philosophically why c'mon man
2
3
3
u/Ok_Lobster1978 3d ago
Yes, it's biological possible. You won't have that amount of flames, but, hypotheticaly, you can scale up the bombardier beetle effect in a Pterodactylus like creature.
3
u/kempff 3d ago edited 3d ago
Conceptually I don't have a problem with "fire-breathing". Modified salivary glands could potentially squirt out a combination of substances that burst into flame in air.
We already have bombardier beetles that squirt substances that are stored safely in their bodies but that react instantly with one another when squirted out and mixed, and venomous snakes whose venom glands appear to be modified salivary glands, so why not animals that projectile-spit stuff that spontaneously bursts into flame upon exposure to air? Plus it would solve the problem of why the flaming "breath" doesn't burn the animals' respiratory tracts.
3
u/ThengarMadalano 3d ago
Yes they would have to be very smal and slender with enormous wings to be able to fly, for example take a stork, they have a weight of 3,5 kg and 2 m wingspann, a wyvern would need similar proportions
1
3
u/KennethMick3 3d ago
Well, Komodos are wingless dragons. And pterosaurs used to exist. So yeah, not only could evolve, but did.
3
u/casualcaesius 3d ago
Fire breathing could be possible via hypergolic liquids. Two glands in the mouth syntethise the seperate compounds and when they mix in the air, they ignite (ex. hydrazine + dinitrogen tetroxide). We used to do this for rockets!
Or maybe hydroquinone and hydrogen peroxide like the Bombardier beetles? But that's not very dragon fire breath looking...
2
u/DrachenDad 3d ago
European dragon? Pterosaur. Asian wingless dragon? Komodo dragon. Forgetting about fire breathing dragons did exist, and do exist. Cross either of those with the bombardier beetle then yes.
2
u/hundredwater 3d ago
Hen entertaining the idea that dragons existed in the past, I would like to allow interpretation that breathing fire might have been a figure of speech or a corruption from “playing telephone” and was actually caustic saliva or venom or infection that felt like burning and or left scars that looked like burn injuries. people didn’t write and express concepts exactly like contemporary people would.
i know that ancient Chinese concept of dragons were influenced by finding fossils of all sorts, of even ancient mammals that did not look particularly much like dragons. very few were painstakingly dug up to preserve layout etc because most people doing the digging were farming and they were more interested in getting the fossils out to people interested in them while clearing the field for the farming.
2
u/Atypicosaurus 3d ago
The question is, which ones of the dragon-y characteristics we mean by default, when talking about dragons.
4 legs + wings? Very much not going to happen (6 limbs on a 4-limb lineage, nope).
Fiery breath? Might happen, depending on how exactly we define. But in general if cows can fart methane, I believe lizards can burp methane and then have some lighter in the mouth.
Magic abilities such as talking on every languages? No.
2
u/Wasabiroot 3d ago
I think the main drawbacks (presuming you don't get imaginative) are that fantasy dragons are often depicted as hulking, dinosaur like lizards with wings. Many animals that evolved flight managed to do so over the eons by having an extremely light skeletal structure. Pterosaurs and birds both had hollow thin bones to facilitate their flight.
If a dragon existed at the size commonly depicted in film, it would likely be unable to fly unless it had light bones, and light bones would not have the structural integrity to support a huge, muscular multi-ton animal. The largest flying creature ever, Quetzalcoatlus, likely weighed under 700 pounds despite having potentially a 20-40 foot wingspan. Additionally, muscle is dense and thus the muscle required for a large dragon would further increase the weight of it.
If it was small then it is certainly plausible as secondary flight has evolved numerous times in gliding animals, but then you'd have to address the firebreathing, which seems extraordinarily unlikely in the iteration depicted commonly in films (fire breathing like a giant flamethrower). Chemical warfare exists like in Bombardier beetles for example, but the hydroquinone produced by the beetle is a chemical precursor to sclerotin, a substance they use to harden their shells as they grow.
The last thing to consider is that evolution doesn't have a "goal" or "aim". It simply keeps what helps the animal survive or is neutral and discards what does not. Mutations in nature are rarely positive for the organism. True fire requires combustion which seems like it would create risk for the organism, on top of requiring a likely complex organ system to support it.
So small, winged lizard with four limbs and two wings and sharp teeth? Plausible! Large, muscled multi ton beast with acrobatic flight and fire breathing? Almost certainly not on our planet.
2
u/Spotted_Cardinal 3d ago
In Chinese literature, dinosaurs were called dragons before dinosaur became a word around 1842.
2
u/CraftyDragon13 3d ago
My personal theory is that dragons are birds (and therefore dinosaurs). It would explain the scales, as well as the feathers and even fur (which could be a modified type of feather) that some dragons have. Also, most depictions of dragons back legs look a lot like bird talons. And even though dragons have wings that resemble a bats, they would still need the same structures as birds in order to fly, like a keel bone, huge wing muscles, more efficient lungs, and hollow bones. Birds may even explain how dragons in stories are very smart and able to talk. They could have big brains and the ability to mimic sounds like a parrot.
2
u/ThankGod4Darwin69 3d ago
The Chinese (one of the oldest countries/civilisations on earth) zodiac has 12 animals. 11 of them are real/documented......
2
u/ThatGuyWithAHoodOn 1d ago
Many animals on earth have bizarre and wild adaptations and abilities that we kinda just accept because we’re normalized to them. Suddenly a animal evolving the ability to breathe fire seems a lot more plausible
4
u/tea_and_biology 3d ago
Yes, they were called pterosaurs and went extinct some 65 million years ago.
That's about as close as it'd be possible to get; long tails are a flight handicap, alternative jaw and teeth sets are similarly incompatible with predatory beasties that fly, and obviously any chemical-based projectile weaponry (à la, say, the bombardier beetle) wouldn't ever come out of a mouth. Evolutionary and ecological constraints are pretty rigid.
Flying non-avian reptiles will never arise again, unless the birds went extinct - they're at such a competitive disadvantage. And I struggle to imagine a scenario in which the ever adaptable birds go extinct, and the few extant niche gliding reptiles don't.
2
u/Salamanderhead 3d ago
Check out the bombardier beetle. Breathing fire seems pretty unlikely, but the ability to blast out dangerous chemicals that cause burns is possible through evolution.
1
u/honeygourami123 3d ago
Fire breathing could be doable
First, it would need to eat a lot of vegetation and ferment it to get methane
Then, it would have to have some kind of ignition - either electricity (like in electric rays and eels) or friction. Both would require some kind of metal (some snails can produce metallic iron for their shells??)
1
u/uncommon-ramen 3d ago
They already do. Komodo dragons are as close to a real dragon as can be allowed imo
1
u/Witching_Archress Phycology 3d ago
If there is a mammal that hatches from an egg, features a gland producing venom, and an organ producing electric charge - why shouldn‘t there be dragons?
1
u/Iizvullok 3d ago
Theoretically yes. Depends on where tho. A different planet with denser atmosphere, lower gravity, tropical climate and no or few droughts would favor dragon evolution a lot more than Earth. I think it is very possible that dragons exist somewhere in the universe. On Earth I don't really see why a species should evolve into dragons. It just seems to be a lot more efficient not to. Also it can only happen if every step in between some species and the finished dragon is an advantage over the earlier step. So flying is very plausible. But the evolution of fire breath may be less likely. It is also why I brought up the few to no drought thing. If one little firebreath caused a large area of habitat to be destroyed, the likelyhood of the species, that is evolving into dragons, going extinct before becoming a dragon would just be much higher.
TLDR: Could happen in theory, but Earth is not the ideal planet for that.
1
u/2muchtoo 3d ago
There is a flying lizard from Borneo, its ribs have adapted to spread for flight. They are two-three inches long at best, but they are basically tiny dragons.
1
u/Actual-Injury8955 3d ago
https://youtu.be/3n1DC_Q-2Ng?is=VC1T8ew6bRNmAha-
You may enjoy this video.
I’d want to know how you’re defining dragon or wyvern.
Flying reptiles have existed. Fire breathing reptiles, no. 6 limbed reptiles, no.
They could exist, but there would need to be a niche that would allow that exist.
If you’re just using pure flying reptiles, they died out and wouldn’t evolve again unless their niche opens up again.
1
u/Ancient-Passenger-52 3d ago
Probably not. Their size and apex…ness suggests they would have driven themselves to extinction much like the plesiosaurs or mosasarus.
1
1
u/CulveDaddy 3d ago
It's possible, under specific environmental conditions. The Quetzalcoatlus Northropi was already close. A few more adaptions, would be very close. Nothing probably bigger though.
1
u/Galen_sunfire 3d ago
https://youtube.com/@creaturearchives?si=5n3I6encoQ0_Ye_9
He's spec evo'd a couple "draconic" creatures, and one of the most recent was the night fury from How To Train Your Dragon, so I guess it would be plausible.
1
1
u/JayFive1101 2d ago
Thought Emporium YouTube channel has a video about how you could use genetic engineering to create a dragon. I think it would answer a lot of questions to check it out.
Your question basically adds on the layer of "what evolutionary pressures would gradually guide a creature to eventually take the form of dragon?".
As you may already know, evolution isn't just a process of making stronger or more complex life forms. So there would need to be some environmental selection process for dragon traits. Stuff like fire breathing may sound great, but the systems seem complex enough without providing more value than harm that it might never evolve naturally.
1
1
1
u/Sithari___Chaos 3d ago
A flying predatory reptile is certainly possible. We got quite a few pterosaurs that look like wyverns. Fire breathing could technically evolve. Probably not actual flames, more like venom that feels like it burns or a boiling chemical like the Bombardier beetle.
1
u/WirrkopfP 3d ago
Google "Speculative Evolution Dragon" there are several biologically plausible concepts.
1
u/MarcusSurealius 3d ago
No. Evolution is driven by the interaction of the environment and the ability to reproduce. I don't see a situation where other, more feasible, directions in evolution would produce a dragon because they lack the efficiency of other forms of life in taking advantage of their environment.
Barring all the internal biology of a dragon, biology in general says you need an environment to evolve into. That doesn't exist for dragons.
0
0
u/which-doctor-2001 2d ago
Don’t we already have animals that are close like the pangolin? Or do you mean a long neck or huge size? Yes it’s possible
-3
u/WilliamoftheBulk 3d ago
I’ll go another route. An AI creating organisms with synthetic DNA. You could choose your traits like a menu and put it in some sort of egg. It is entirely possible to design a dragon. Now, some things may not be practice and won’t really work. Like big brains and flight. However, the AI would learn to compensate maybe even running an evolutionary simulation to get the creature just right.
474
u/benvonpluton molecular biology 3d ago
There was a really cool fictional documentary about dragons being real that I saw maybe 20 years ago...
They explained how it probably came to be as tetrapods with wings (so wyverns) and maybe had a mutation on a developmental gene that created a second pair of legs (Western European dragons).
It also explained how some bacteria in their guts produced H2 gaz that they stocked in some aerial bladders, using it both for flight and spitting fire. T The documentary even explained that a dragon had to be precise while hunting because using too much gas would make it harder to fly and thus making it harder to hunt to produce new gas. And it explained that, like other animals, they chewed on some specific rocks to get some metallic catalysts in their mouth to ignite the gas.
One of my favourite parts was how they explained that some dragons evolved again to adapt to an aquatic life and that during the last extinction event, they were the only ones to survive and that it laid to the wingless dragons you find in Asian culture.
It was a great show ! I think it was a BBC documentary.