How do bearded dragons exactly change their color?

[ChileanTaco]

When taking Taco out, because of my interest in biology (and me being very fond of patterns and structures), I like to observe him very closely, e.g. how he moves his eyes, how different body parts look, the exact structure of scales, and also... how I think he changes his color.
I've seen that in between the scales, there is always some very vivid orange and yellow visible. Reminding me very much of some of the usual photos of molten lava, e.g. https://static.vecteezy.com/system/...ava-flow-cracked-lava-ai-generative-photo.jpg
Then seeing (on photos) that leatherback and silkback dragons look usually more vivid, I was thinking: Is the color change happening by making the scales more transparent vs. more opaque (and grey), and the color we see is a mix of the orange skin underneath and the color of the scales on top? Like you would have e.g. something colored in vivid orange and yellow, and then you put a layer of a material that can adjust its opacity (like those eyeglasses that automatically get darker in sunlight) on top, and so the e.g. orange is not really gone but hidden under another layer through which you see more or less and when this layer gets darker the orange seems to "change" into e.g. a brown color?
Are there maybe any papers on that? I found more on chameleons, but I could guess there might be something on bearded dragons?

(Taco then wanted to go back into his enclosure. But now I know which photos I want to take the next time he wants to come out Also found one of his beard spikes is yellow but has a single orange freckle Don't know if he shows that all the time, but that's also on my photo list )

 

[BuddyBeardedDragon]

Bearded dragons change their color (i.e black stress lines) as a result of the movement of certain pigments in the chromatophore cells in their body. Chromatophores are cells that contain produce colors. I am no vet or biologist so I can't provide much information about it, but here is a very detailed description about their color change : Cyclic Colour Change in the Bearded Dragon Pogona vitticeps under Different Photoperiods Their DNA is the one that picked the color of each individual bearded dragon though. Each one has a slightly different color from the next.

 

[ChileanTaco]

This is what I have read, as a general description. But were are they? In the scales and what is below stays their color, or everywhere? So e.g. when going from "orange" to "brown" is it really that change, or that underneath orange stays, but now above that a layer gets darker?
For the stress marks I won't wonder much (just going from white(ish) to grey), but I meant more on their back and head as that's where I observed the orange and yellow between the scales and then wondered if their "brown" is just a mix of that with the scales on top getting lighter and darker.

But maybe this paper answers this. I will read it for sure (and will post about it here).

 

[Chris.]

Not sure on this but if you do some more research, maybe look for chameleons as there might be more research on those compared to bearded dragons.

 

[ChileanTaco]

@Chris.
I had already looked this up multiple times, i.e. many years ago out of my general interest in reptiles and all kinds of wildlife (also for octopus), but I'm still missing certain details: i.e. which skin layers are involved and what are the exact pigments in which kind of cells. Usually I cannot find more detailed information than that they are redistributing pigments in their skin and that a higher concentration gives a darker color, and that also the reflectivity of nanocrystals is changed. (Okay, nanocrystals, no problem - close to my field of work. But which pigments? At which wavelengths do they absorb and reflect? Where are the cells containing them?)
For this part, I'm still (on my own) trying to find some papers.

 

[Rocky2022]

In non scientific terms.... happy, sad, sick, hurt, hot, cold ...Beardies cant speak so they express themselves via their colors (at times, demonstratedby actios).

Ruby hates me but changes colors when I pick him up. He glows. Colors always tell everything.

The more you interact with your beardie, the more you'll learn.

Be careful, they are often stubborn and spoiled and bound to make your heart turn colors.

 

[ChileanTaco]

In non scientific terms.... happy, sad, sick, hurt, hot, cold ...Beardies cant speak so they express themselves via their colors (at times, demonstratedby actios).

That's the why, but I was asking for the how

The more you interact with your beardie, the more you'll learn.

I interact with him a lot, and I think I can "read" him very well. Also what's the difference between "dark" out of stress, because of camouflaging, because of getting cold, because of just started heating up...

(Yes, I like it that this gives them a way to express themselves, also allowing us to know more about what's going on.
I often struggle with understanding human facial expression and human nonverbal communication as a whole - I'm on the autism spectrum. I usually can learn the expressions of animals very well, however. Likely because in everyday life, to at least get a bit of that human nonverbal communication I have to look and think and learn very hard. So I'm used to doing that. Differently than many people who are just a master in understanding human nonverbal communication intuitively (I really often wonder what people can read from human faces and in general their nonverbal communication - when it for me shrinks down to 2 - 4 expressions like "sad", "happy", "very angry", "neural"), thus not having the need to pay that close attention.)

 

[Rocky2022]

That's the why, but I was asking for the how


I interact with him a lot, and I think I can "read" him very well. Also what's the difference between "dark" out of stress, because of camouflaging, because of getting cold, because of just started heating up...

(Yes, I like it that this gives them a way to express themselves, also allowing us to know more about what's going on.
I often struggle with understanding human facial expression and human nonverbal communication as a whole - I'm on the autism spectrum. I usually can learn the expressions of animals very well, however. Likely because in everyday life, to at least get a bit of that human nonverbal communication I have to look and think and learn very hard. So I'm used to doing that. Differently than many people who are just a master in understanding human nonverbal communication intuitively (I really often wonder what people can read from human faces and in general their nonverbal communication - when it for me shrinks down to 2 - 4 expressions like "sad", "happy", "very angry", "neural"), thus not having the need to pay that close attention.)

Fascinating...when all else fails, ask (the human that is). No one wants to be misunderstood and one may learn something. One may also check their own assumptions. I could go on and on but this is about beardies. I find your posts fascinating and I bet you'll discover something that teaches us all something new about beardies.

Lastly, you probably haven't checked my posts. I am usually veering to the left when everyone else is leaning towards the right. Hence me answering the why lol.

 

[ChileanTaco]

Fascinating...when all else fails, ask (the human that is). No one wants to be misunderstood and one may learn something. One may also check their own assumptions.

Doing this indeed often. (I don't mind being odd, I'm naturally very direct, but sometimes it's, I learned over time, just not beneficial to ask, or not possible (one can't ask a movie ) - but then I might ask others I trust if around.) This is why, in addition to asking when it's somewhat appropriate, I also stick lot to training material.
Nevertheless, I like it to learn how to better understand whatever living being, especially those I'm around often, just to avoid said misunderstandings as often as possible and to be able to show the empathy I have. Also to my beardie of course
A few days ago I recognized Taco (who is only running around on the floor since a few weeks) is always running to the door of our apartment. Each time I let him out: to the door. He was never out there, door has no window. After sitting in front of the door and scratching at the door, he runs to a bookshelf and runs back and forth multiple times. No black beard or such, just "happy explorer" style. First I thought he looks for a way to climb that bookshelf, or he feels a little draft at the door.
Then I found out: As there is a large window on the other side of the wall, he casts a very sharp shadow against both the door and the lower part of the bookshelf. That's what puzzled him. I remembered an article I read about behavioral biology, that most animals who don't or barely pass the "mirror test" immediately pass it very well once an object is held next to them, so they see that object "real" and in the mirror and then can conclude that this thing "mirrors" and that the being they see is actually them. Might work with shadows? I moved my hand forth and back next to him so it's visible to him and he sees it in the shadow, too. Taco: Looking to the shadows on the door, to my face, to the hand, and again.
Doing this on two days, he now just looks briefly into the direction of the shadow when I let him out, then does something else. Love that, as in that way I also helped him to better judge things he encounters in "human world".
(I won't irritate my dragon with such as shadows, mirrors. But seeing them from while to while in "human world" just cannot be avoided, especially for the shadows. I like giving an animal a chance to learn and this obviously worked.)

 

[Rocky2022]

I totally understand. When that occurred with Rocky, especially walking into the wall....my first thought was that he couldn't see the color white.

I don't find you odd at all, I learned so much from your posts.

Beardies love to explore. There are so many WHY questions that I still can't figure after 2 years but I bet that you can.

For example, whether through a window or directly outside, why do beardies look at the sun? They turn their heads completely then look at the sun. After doing so, they carry on exploring but they HAVE TO DO IT.