Quote Originally Posted by Iscah View Post
As for how they developed "armoured" sections in the first place... evolutionarily speaking, they're going to develop where they're needed for protection - or rather, any randomly-evolved scale placements that contribute to their survival are likely to be passed down to the next generation.
Could also be sexual selection. It's the reason humans grow excessively long hair on their heads when there's absolutely no evolutionary advantage to doing so... it was more attractive. Could be the same for Au'ra. An ancient Au'ra ancestor could have sported a more heavily armored body, but over time less armor and more skin became more sexually attractive and so that's the trait that was passed on even if direct survival and natural selection wouldn't have gone that way.

Quote Originally Posted by Iscah View Post
Given we're dealing with horns as well as scales (the far bigger evolutionary question, really), developing armour around the face is actually probably a valuable defence against accidentally being gored by your partner... as is having the males and females be different heights so they're not going to poke each other in the eye.

It's the closest thing I've got to an explanation for the height differences, anyway...
That's actually a pretty good theory for that.