Before I begin, (and I really can't stress this enough) I just want to say that this is a playful approach to attempt to explain whether or not a real-life dragon could theoretically exist. This is not meant to be part of an evolution-vs-creationism debate, nor is it meant to be anything other than entertainment based off of some aspects of existing biology . I will simply be comparing actual evolutionary traits to what we consider to be a mythical creature, so this post is fantasy based off of science (if you are not a big supporter of evolutionary science, just try to enjoy it as just an entertaining read). I do not believe dragons have ever existed and I am incredibly doubtful such a creature will ever exist outside of our imaginations. However, the question I will be addressing today is, as astronomically unlikely as it is, could it be theoretically possible for such an animal to exist?
Before we tackle the big question, we should first consider the cultural significance of the creature we know as the dragon. Throughout human history, there have been thousands of myths and tall tales, stories of gods, monsters, heroes, demons, artifacts, etc.; the dragon is just one of countless fantastical beasts. There are plenty of parallels and similarities between the stories of different cultures, but what makes the dragon so special is that it has been prominently featured in the myths of most known cultures and peoples.
"Most peoples at some point in their history have believed that the dragon was real." -introduction to An Instinct for Dragons, anthropologist David E. Jones Source
That's what makes the dragon so interesting from an anthropological standpoint; it has appeared in the written tales and verbal stories of many civilizations around the world for thousands of years. The giant feathered serpents of the Americas, the European dragons, snake-like Asiatic dragons; though they may differ slightly in form, the beast persists across human civilization. So where does the myth come from, and why is it prevalent in so many cultures? Anthropologist David E. Jones, author of An Instinct for Dragons, believes the answer comes from primates. Citing the vervet monkeys of the African savanna, Jones says there are three big threats the primates face: snakes, birds and big cats. He hypothesizes that the classic dragon is an amalgam of these three basic primate fears, a creature with the scaled skin of a snake, the wings of an eagle and the claws/jaws of a big cat, combined into a fierce memory in a primal part of our brain. It's a theory that can't be definitively proven, but could fear of predators have created the dragon? Other cultures have built their myths around physical evidence, in most instances dinosaur fossils and footprints. For thousands of years, Chinese culture regarded dinosaur bones as the preserved remains of ancient dragons. Whatever the source for the myth, the dragon is truly interesting as it has remained so ubiquitous across such diverse cultures.
"At the heart of every legend, there is a grain of truth." - Michael Scott, The Alchemyst Source
Alas, despite such prevalence in human culture, we have no evidence to suggest dragons ever actually existed. Though it is nothing more than a creation of the human mind, could it be possible (nearly an infinitesimally small chance, but still) for nature to create the dragon? We are going to break down some aspects of dragon biology, and see how they compare alongside existing biological traits.
Size and Shape:
If I were to ask you to name the first animal that came to mind that best fit the description of a dragon, you would likely tell me some species of dinosaur, maybe T. rex. It's a reasonable comparison; dragons are generally known to be exceedingly large and are typically covered in reptile like scales. They are carnivorous beasts that are content to gobble up humans (especially knights) and livestock, and if one actually existed, it would likely fill an environmental role similar to T. rex as an apex predator.
I mean, slap some wings and spikes on there and you have yourself a dragon.
So we know that a "dragon-sized" animal could easily exist...the dinosaurs are proof of that. In fact, giant reptiles dominated the Earth for millions of years long before humans ever appeared on the scene. So we can't rule out the existence of dragons based solely on their size...although perhaps their size is the most realistic of some of their fantastic biological properties.
Next let's consider their body shape. Dragon body shapes pretty much come down to two forms; the first is basically that of a serpent. The Asian Lung, the Greek drakon, the Old English wyrm, the Norse Nidhogg, all of these creatures are elongate monsters with reduced legs or lack limbs entirely. Though they might bear some extra features (spikes, horns, small wings, etc) this form is the more plausible of the two dragon body types. A gigantic snake might seem like a myth, but these creatures have already existed on our planet in the distant past. If any critter could pass for a serpentine dragon, it would be Titanoboa, a massive snake (up to 50 feet long and 2,500 pounds) that existed during the Palaeocene epoch. This giant serpent lurked in the tropical swamps, attacking prey with powerful jaws like a crocodile. It was no dragon, but Titanoboa had the basic design of a serpentine dragon down pat. With a few extra adaptations, it would have been real easy to pass one off as a real, live dragon.
Top: an artists depiction of a serpentine dragon; Bottom: the skeletal remains of Titanoboa
But when I say dragon, most of you probably pass on the serpentine form and favor the more iconic, European form: a four-legged, dinosaur like beast with leathery wings growing from the shoulder blades like the one pictured below. It's a cool looking beast to be sure, and because of its vague similarity to a dinosaur, one might believe such a fantastical creature could plausibly exist under the perfect evolutionary conditions. Unfortunately this form has pretty much zero chance of ever existing because of one major feature/flaw: it's wings.
Wings:
Vertebrates have evolved wings three separate times, in pterosaurs, birds and bats. Though their wings come in different shapes and sizes, some comprised of feathers and others of leathery skin, the wings of all of these animals arose roughly the same way; non-flying ancestors gradually transformed forelimbs into wings supported by modified fingers (source). They did not just grow wings, rather they traded their arms for wings (to put it simply; obviously it's much more complex than that). This is where the form of the four-legged, winged dragon becomes a problem; if it's wings evolved in the same manner as other vertebrates, it would have to be a six-limbed animal. The idea of a six-legged vertebrate animal is not necessarily impossible, but the evolutionary leap to that design is massive, and not likely to just occur.
However, there is a similar, four-limbed dragon that is becoming increasingly popular in modern films and pop-culture. Anatomically it is far more realistic, as it bears only wings and hind legs, and has ditched the forelegs, giving it an appearance that more closely resembles a bat (at least as far as wings are concerned). Commonly known as the "wyvern", many popular dragons have adopted this design, from the Hungarian Horntail of the Harry Potter Films to Smaug, the dragon of the Hobbit. The design is favored because it is not only sleeker and cool-looking, but it is more biologically appropriate.
"Surely a creature that big could not actually fly right?"
Getting a beast that size off the ground is no small feat, but it has been done. Azhdarchid was a prehistoric pterosaur, the largest creature to ever dominate the skies. If they existed today, the largest azhdarchids would be of a height comparable to a giraffe, with a wingspan over 36 feet (that's a size similar to most small aircraft); if dragons were to arise from any group, the azhdarchids were it. To get in the air, a dragon would require certain anatomical adaptations; unlike birds, which are larger-bodied because 90% of their launch power comes from the huge muscles in the legs, pterosaurs launch into the air by using the sheer strength of their arms/wings.
"They don't need to worry about carrying all their leg muscles into the air with them after they've taken off. That of course means that they can get much bigger." -Mark Witton, University of Portsmouth, UK Source
However, to even still have a hope of flying, dragons would have to adopt the sleek, relatively small-bodied design of pterosaurs. Large dragons with bulky torsos and thick hindlegs would be completely unable to rule the skies.
Intelligence:
In fantasy tales, dragons can range pretty widely in intelligence; some are brutish beasts with only a keen predatory sense while others are able to talk and are incredibly wise sage-like figures. Intelligence is not something most people really consider when discussing reptiles; even scientists have long called certain portions of the brain associated with basic functions, such as breathing, "reptilian". It was believed that reptiles largely existed on instinct and not true intelligence, however very recent studies are quickly revealing that that is not the case at all.
"Reptiles can master many problems that mammals can. Complex-problem solving, reversal learning, social learning, complex sociality, tool use and individual recognition have all been discovered." -Gordon Burghardt of the University of Tennessee in Knoxville Source
I have written in the past about my experience training American alligators and their long underestimated intellect. I've been working with a young alligator for the past 4 years and I have witnessed first hand their capacity to learn and analyze things. I often tell our guests that the gators are studying them just as intently as visitors watch them. One of our gators, Stella, is a particularly tricky little reptile. During her early training, my biggest struggle was that Stella grew particularly good at reading my body language, and was able to anticipate my movements. Sure, she won't be demanding I answer riddles, spilling the secrets of the universe or even talking any time soon, but the capacity for learning and adapting is there. If dragons did exist, they would not talk like Smaug, but they would still have a terrifyingly intuitive predatory nature.
Immortality:
Dragons are often depicted as thousand-year-old beings, creatures that are either immortal or incredibly long lived. Without a brave and noble knight to slay it, a dragon could terrorize the people for centuries. We are starting to get into some of the more fastastical dragon traits here, but could there be any evolutionary truth to their longevity? Could a creature possibly evolve the ability of true immortality and live forever? The answer is yes. In fact, one already HAS.
Turritopsis dohrnii, more commonly known as the immortal jellyfish, has found a way to cheat death. In fact, barring consumption by a predator or being struck by disease, there is no known way for them to die! What is their secret? Immaturity. Where most jellyfish species mate and then die, the immortal jellyfish has taken a different approach: after mating, the jellyfish reverts back into a sexually immature state to start the life cycle over. And they can do this again. And again. And again...
Now, obviously there is a huge difference between the simple-bodied jellyfish and the mythical dragon. Unless a vertebrate figures out how to revert back to its younger self, no dragon-like creature is going to be truly immortal. However, if we look at the reptile clade, we can see several instances of impressive longevity; one of the most well known examples is the Galapagos tortoise which can live well past 100 years. But longevity usually comes with a metabolic cost; the key to living a long life is to lead a very slow life. A good example of a dragon-like creature would probably be the tuatara, pictured below (heck, it REALLY even looks like a dragon!). Like tortoises, this lizard-like nonlizard can live to be over 100 years, however these animals have a very slow reproduction rate as a result; sexually maturity may take decades, and females will only lay eggs once ever 4 years once mature. In order to achieve its extreme longevity, a dragon would likely have to be a creature that lives, metabolizes and reproduces at an incredibly slow pace.
An Eye For Treasure:
Smaug is the perfect example of the dragon's lust for all things glittery and shiny. The beasts regularly sit atop mountains of gold, jewels and treasures, ready to kill anyone who dare attempt to steal from them. It all sounds a lot like the fantasy version of a video game boss battle; kill the baddie then collect the loot! But what drives the dragon to hoard this treasure trove? Could there be an evolutionary reason for this behavior, and could it be seen in the real world?
Perhaps the hoarding is a habit that is part of sexual selection. The best, most realistic parallel to explore would be the bowerbird; as mating season approaches, male bowerbirds fill their bowers with all sorts of "treasures"...anything from berries to broken glass shards. Females will then select mates based on the quality of their bowers; "if a male has the energy to seek out and arrange the best possible bits of glass, he probably has good-quality genes that will ultimately be passed on to his children" (source). If dragons were to exist, and females were to exhibit a sexual preference for males that were able to gather and arrange shiny objects, it wouldn't be entirely impossible for them to collect these treasures to line their own bowers.
Firebreathing:
You were all waiting for it. You KNEW it was coming; the most fantastical ability in the dragon's arsenal. And now you can't wait for me to try to explain how a creature breathing fire is even remotely possible. So lets just dive right on in here.
No. There is no animal that breathes fire. It just doesn't happen, and honestly, it is extremely improbable that it ever will (I'd say impossible, but nature does some really weird stuff and I don't wanna jinx myself). It's not likely for a creature to ever exist that truly expels fire, but could it be even remotely possible for it to happen?
In the 2002 film Reign of Fire (Christian Bale, Gerard Butler, and Matthew McConaughey fighting dragons, good stuff!), Bale's character explains that the dragon's fire is simply an enhanced form of venom. The dragon has two isolated venom glands that can shoot two types venom in the same manner a spitting cobra would. The two different venoms mix as they are expelled, igniting and creating a natural napalm that burns everything to a crisp. It's a nice movie explanation that we can live with and move on with the plot, but in our hearts we know it's complete nonsense. Or is it?
Sometimes truth is stranger than fiction, and this sort of chemical warfare is seen in the animal kingdom, although not among vertebrates. The bombardier beetle, as its name suggests, has developed a rather bizarre means of defending itself by shooting attackers with a caustic compound. In the beetle's abdomen, two separate reservoirs hold two chemical compounds: hydroquinone and hydrogen peroxide. When disturbed, the compounds are mixed at the back of the abdomen, and the resulting reaction brings the mixture almost to the boiling point (of water) and the gases produced cause the spray to be ejected. Sure, the beetle isn't spewing volcanic dragon fire, but the scalding mixture is enough to painfully burn attackers and even kill other small insects. It is again highly unlikely that such a trait would arise in reptiles, or result in the creation of actual fire, but nature has proven time and again that it is more than capable of seeing the improbable become reality. The mixing of chemical compounds to kill targets is already a weapon in evolution's vast arsenal.
So, could dragons ultimately exist in the perfect world? There are a couple answers to this question but yes, under the most perfect evolutionary conditions, a creature that we would recognize as a dragon could exist, though it obviously is remarkably, astronomically improbable. The other answer essentially comes down to what you would qualify as a dragon. Many species have existed and do exist that could pass as a sort of "dragon" depending on how you wanted to define the creature, such as pterosaurs, Titanoboa, and giant reptiles. True dragons will more than likely remain a subject of myth and legend, but the traits and biological properties of the dragon have already been invented by nature and are in use throughout the animal kingdom. If evolution can create all the traits of the dragon, perhaps it could combine them into one beast under flawless conditions.
I hope you all enjoyed reading this post as much as I enjoyed writing it! Dragons are my favorite mythological figure (I took a few mythology classes in college alongside my biology courses), and I always like the challenge of trying to find parallels between biology and mythology. It bridges the gap between fantasy and reality and makes you think a little bit about how these legends arose and how significant they were. Though the dragon is likely to remain a beast of fiction forever, it remains an important symbol for mankind.
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