In the land of Dracoriri, there are dragons. There weren't always dragons, once humans were the dominant species, but then magic-an unexplained phenomenon-invaded earth alongside creatures from another world, the foremost being dragons exist and now humans have fallen into a new niche. But, as dragons emerged, a strange phenomenon was observed by humans among the new species: variable intelligence.
Some dragons acted with an animal cunning, clearly intelligent but not quite sapient, incapable of speech and driven by instinct. Their eyes were dark, and as a general rule, these "darkeyes" or drakes resembled animals, like how Crashdrake resemble cassowary or how Stealthdrakes resemble Velociraptors.
However, other dragons had intelligence rivaling that of humans, being clearly sapient and capable of both (human) speech and higher thought patterns, with brightly colored eyes and glowing pupils. These dragons tended to look more like how 'traditional' dragons; Silverns are sheathed in silver scales, clearly reptilian, and have a wyvern body plan, with two batlike wings and two legs, while Goldrakes are big, covered in golden scales, with two batlike wings and four legs.
Got it? Good, because this is where it gets tricky. Brighteyed dragons never have darkeye offspring, they're never born darkeyed. However, darkeyed species can be born brighteyed, or can have brighteyed children, and its rumored they can even become brighteyed somehow, though no one has confirmed this or how it could happen. Furthermore, if a darkeyed dragon has a brighteyed child, it means nothing-such dragons are not in fact more likely to have brighteyed children, and neither are their offspring.
I have no idea how this could work, so here I'm asking: how could this work? How could dragon intelligence be so consistent and yet so inconsistent at the same time?
Thank you for your feedback, I appreciate it!
Note:
Thanks to Palarran for bringing the need for clarification to my attention. Many of the "darkeyes" or drakes I've envisioned so far have indeed been wingless, but drakes can and do have wings depending on species.
Furthermore, brighteyes are not limited to the same body plan as Silverns and Goldrakes. As examples, two species of brighteye, Chimerake and Swordrake, are wingless, and the two are quadrupedal and bipedal respectively. Furthermore, Mesmerake, another species of brighteye, are serpentine and possess only two arms, maybe a pair of wings, and of course fins (they're based on Sirens, the fishy not the birdy kind specifically).
As for interbreeding, no brighteyes and darkeyes do not interbreed. Why would they? Brighteyes have intelligence and sophistication far beyond that of darkeyes, and darkeye species are seen as inferior (for reasons that should be obvious). It's pretty much unthinkable.