Based off of this question from Worldbuilding SE.
In that question, I talked about how the scrotum and buttocks of various animals have a blue color because of thick deposits of collagen in those areas. I wanted to make a race of elves that used this mechanism to achieve blue skin all over their body.
Now, I thought that the thickness of the collagen layer was what was behind the structural coloration of animals like baboons and vervet monkeys. However, I have since learned that it is also the way the collagen is arranged that makes that color occur. That made me think that to achieve my desired effect, I wouldn't need to make the skin exceptionally thick. I could just rearrange the collagen humans already have and not change the thickness at all.
I'm having a hard time understanding the underlying mechanisms behind what makes the arrangements of collagen different, and why it wouldn't occur over the whole body.
Thus my question is twofold:
- Is it the structure, or the thickness of this collagen layer that makes the structural color work?
- Does the way the collagen is structured in these areas make the skin function differently than normal skin? (I.e. Is it less stretchy? Is it more fragile?)
(I'm sorry if this is off topic, I was thinking that since the focus of the question is on how the collagen works that it would be better suited here than on Worldbuilding)