What is a dragon?

[Corva]

What are the most important attributes for a creature to be considered a dragon?

Ones which immediately spring to mind are four legs, wings, breathe fire, scaly, intelligent. How important are each of these traits (obviously at least some of them are critical - a two legged winged creature with feathers that doesn't breathe fire isn't a dragon)? Can a two legged winged pre-sapient reptilian creature with regular breath be considered a dragon, or is it "just" a wyvern (still a creature you want to be for you, not against you, particularly if you can ride it - the main advantages dragonriders have is aerial superiority in a world without aircraft or rockets)? Does size matter at all - is a shoulder sized (adult) dragon properly a dragon?

[BeneathTheStarlight36]

i was going to say "has to be a reptile", but then there are those, like, fuzzy dragons that i guess are more popular in eastern mythology? so i don't really know what to say.

basically i guess, people have a general idea of what a dragon "should" look like, and as long as it looks enough like that general idea, and is a living organism, then it's a "dragon".

i don't know how to be any more specific, because everything i think of would have exceptions. (breathing fire --> water dragons; four legs --> wyverns; etc)

[Corva]

Perhaps a set of attributes, with a creature being a dragon if it possesses most of them? So a fire breathing flying reptile with two legs would be a dragon, and a flying reptile with four legs and no fire breath would also be a dragon, but the first without fire breath would be a wyvern (wiki tells me the difference, in British heraldry, is the number of legs, but other European countries don't follow this). Or perhaps the key distinction is the fire breath.

Wyverns are underrated in fantasy, I think. Wyvernriders wouldn't be able to fight dragonriders that easily (though add in someone with a crossbow...), but they would be able to see the entire battlefield and move people around quickly and out of the range of medieval weaponry. As well as taking potshots at people on the ground.

[BeneathTheStarlight36]

i always thought wyverns were a "type" of dragon.

[Falconer]

I don't know if you want to define the species based on phenetics alone; right now the best we can try to achieve without a detailed understanding of physiology would be a folk taxonomy with educated guesswork thrown in.

From an evolutionary standpoint, I would imagine that dragons might be split across the Animalia kingdom, based on the varying number of appendages. For example, your classic wyvern has four appendages (two wings, two legs), Oriental dragons have 4 legs, and I expect lindwyrms, the Oriental dragons with two legs, and those feathered ones with only wings have vestigial limbs to bring the count up, like snakes. Most of these guys could be placed as a group buried somewhere in Reptilia; easy peasy.

European dragons are the problematic ones. The 4-limb rule of thumb is older than Mamalia; it's though to date back all the way to when we were fish, and has never changed since. This leads to three possibilities:
* European Dragons evolved on a completely separate evolutionary path than every other land animal in the world, a path that produced ONLY the European Dragon. (Doubtful)
* European Dragons are NOT a separate species, but a mutation or birth defect of the wyvern that produces a extra pair of limbs, probably stunted and non-functional.
* There are no European Dragons, just wyverns. Early historians got their information from witnesses who were either panicked or stupid, leading to a mistaken impression that the monster that just ate Bessie had more limbs than it actually did. (Most likely)

[Corva]

Particularly if the wyverns in question had claws on their wings and used them as legs when on the ground, like those in Reign of Fire, or A Song of Ice and Fire. I can easily imagine someone panicking and thinking they were separate legs and wings.

[Falconer]

It also makes more sense from musculature sense, as the chest muscles for a set of forward legs are in the same area as the muscles for wings; in order to have both, a dragon's chest would have to be freakishly muscled and the two sets would likely interfere with each other.

Fire breathing, on the other hand, I don't think that'd be difficult to incorporate, even if not all members of Draconia exhibit the trait; I would even go so far as to postulate that the trait exists in all species, albeit as non-functional in some, or adapted into something different. For example, a fire breath made by mixing organic napalm could be moderately tweaked to instead exude some kind of caustic substance.

[BeneathTheStarlight36]

The 4-limb rule of thumb is older than Mamalia

if humans, somewhere, developed an extra set of arms, wouldn't they still be humans?

[Falconer]

The 4-limb rule of thumb is older than Mamalia

if humans, somewhere, developed an extra set of arms, wouldn't they still be humans?

I don't want to sound dismissive, but I doubt that would happen. Reason why are the annoyingly limiting Hox genes. To summarize it, basically the genes that control number of limbs are ABSURDLY important and tied to many vital systems, and small random mutations to them always have disastrous results. Such mutants rarely if ever survive to birth/hatching, and never make it to sexual maturity. Since mutations in Hox genes never work out well, limb numbers don't change. Even if a human underwent a mutation that added two more arms, they'd be in the wrong locations entirely and wouldn't function. That human would then have to survive to adulthood and successfully mate, and THOSE offspring would have to do the same, etc. Eventually with enough small mutations, those arms might end up somewhere useful with enough muscles to support them. THEN they'd finally start posing an advantage. Until then, they represent (in evolutionary terms) an ungodly level of not just "not useful", but "active setback".

I suspect at some point our genetic engineering technology will advance to the point were we COULD engineer humans with two sets of arms. At that point, since it's only so much speculation, I can only state that the usual rule applies; if humans can mate with such creations and produce fertile offspring, then they're human. If not, they aren't.

[BeneathTheStarlight36]

i was speaking theoretically. if that were to happen, wouldn't the resulting species still be considered "human"?

[Falconer]

Probably not. Such a major change, even if cross-breeding was still viable, would create a pretty substantial social divide. I mean, we'd still LOOK pretty similar, but in the grand scheme of biology we also look pretty damn similar to chimps.

If you look to a lot of popular fiction franchises, you can get a sense of this. I felt like Deus Ex: Human Revolution was a really good depiction of how capable humanity is of ostracizing anyone they perceive as different, and hell, augmentations aren't even hereditary. See also the "mutants" from the X-Man franchise; still close enough genetically to interbreed and produce viable offspring (the science definition of being the same species), yet incorrectly considered a separate species "Homo Superior" by both mutants AND normals. In fact, I think there were even a few mutants with extra limbs.

As for dragons... depends on if they are intelligent enough to have a social structure! Biology doesn't consider reproductive sex in a vacuum of "physically viable"; such social interactions as mating displays are also considered. I vaguely remember off the top of my head that there's some species of birds that are separated reproductive-ly purely because females of one species do not recognize the mating displays of males of the other species and will not mate with them. Certainly a draconic mating display that involves four legs would be outside the capability of a wyvern.