Brightening Color?

[Stefan-A]

well, I have light bulbs of all kinds burning... UV bulbs, regular house bulbs... fluroescent twirly bulbs... no bulbs at all.... I don't really notice a different any which way!!!

What we don't have is a light source that's comparable to the sun in intenisty and that would cover as many wavelengths, especially UVB and UVC.

[reptileparadise]

ditto on what Stefan says.
Our lights don't come near the wavelenght of sunlight. We try though...

My guess would also be food...

I've though about this many times, but then in relationship to offspring.
Will offspring from parents that are kept (very) warm be lighter then offspring of garters that are kept cool? (Black pigments allow more heat to be absorped which is nice for snakes in cool enviroments)

[Zephyr]

Aren't skin pigments also influenced by the type of lighting? In humans, we would call that "tanning".

I'll have to find some pics of my male when he was outdoors in the pen; his colors went from being defined and noticeable to blended/faded. Just like a tan.

[DrKate]

Will offspring from parents that are kept (very) warm be lighter then offspring of garters that are kept cool?

I don't think it would happen in a single generation. For instance... My ancestors on both sides came from (far) northern Europe several generations ago and settled in the mid-Atlantic region of the US - lower latitude, stronger sunlight. Both my parents grew up under those conditions. They should have produced melanistic offspring, since melanin protects by absorbing/diffusing UV light, right? But instead, their offspring (me!) burns after about fifteen minutes in direct sun and pretty much never develops a tan even with very careful sunning. But after thousands of generations? Well, maybe I'd look more like I belong at this latitude.

Semi-tangent: I've been to far northern Europe in the summertime, and I can spend a whole day outside without sunscreen. I don't have any more objective measurements, but it seems like there really is a substantial difference in UV with that fairly small difference in latitude. I was amazed.

[GarterGeek]

I don't think it would happen in a single generation. For instance... My ancestors on both sides came from (far) northern Europe several generations ago and settled in the mid-Atlantic region of the US - lower latitude, stronger sunlight. Both my parents grew up under those conditions. They should have produced melanistic offspring, since melanin protects by absorbing/diffusing UV light, right? But instead, their offspring (me!) burns after about fifteen minutes in direct sun and pretty much never develops a tan even with very careful sunning. But after thousands of generations? Well, maybe I'd look more like I belong at this latitude.

Semi-tangent: I've been to far northern Europe in the summertime, and I can spend a whole day outside without sunscreen. I don't have any more objective measurements, but it seems like there really is a substantial difference in UV with that fairly small difference in latitude. I was amazed.

Isn't that different though? I don't know much about this but...Wouldn't your burning vs. tanning be the result of a skin type?

The snake's change in color is (theoretically) the result of different temperatures and UV exposures. Meaning that all snakes have the ability to"tan", but some are predisposed to a certain hue because of their parent's "tan".

Your ability to change color based on UV exposure is genetic. Not all human's have the ability to tan, but they do have different shades of skin based on the geographical range of their ancestors, who developed their color after thousands of years.

Does this make sense?

[DrKate]

Isn't that different though?

Well... Melanin is the dark skin pigment in snakes. Melanin is the dark skin pigment in humans. The capacity to produce melanin is genetically controlled (which is why you can breed melanistic and amelanistic morphs).

Not all human's have the ability to tan, but they do have different shades of skin based on the geographical range of their ancestors, who developed their color after thousands of years.

I think I may see what the confusion is, though... There are two processes at work. There's the amount of melanin you produce by default (think Irish vs. Nubian). Your basic skin color is genetically controlled. Then there's the amount *more* melanin your skin can produce in response to UV exposure - neither the Irish nor the Nubian change a whole lot between summer and winter, but the classic olive-skinned Italian changes drastically. That capacity to tan is *also* genetically controlled.

So whether you're talking about a change in the default amount of melanin you produce or a change in your capacity to produce more or less based on demand, either way it's a genetic thing and really unlikely to change in a single generation. (Neither my default skin color - ghost white - nor my ability to tan - nil - is consistent with the latitude my parents grew up in.)

And then there are Siamese cats: We are Siamese if you Please, Alaska Science Forum. So I suppose if you ever found a snake with the "himalayan" mutation then yes, it would get darker in cold temperatures! But still not in quite the same way you were suggesting for parents having (permanently) lighter or darker offspring based on their environment.

[GarterGeek]

Well... Melanin is the dark skin pigment in snakes. Melanin is the dark skin pigment in humans. The capacity to produce melanin is genetically controlled (which is why you can breed melanistic and amelanistic morphs).


I think I may see what the confusion is, though... There are two processes at work. There's the amount of melanin you produce by default (think Irish vs. Nubian). Your basic skin color is genetically controlled. Then there's the amount *more* melanin your skin can produce in response to UV exposure - neither the Irish nor the Nubian change a whole lot between summer and winter, but the classic olive-skinned Italian changes drastically. That capacity to tan is *also* genetically controlled.

So whether you're talking about a change in the default amount of melanin you produce or a change in your capacity to produce more or less based on demand, either way it's a genetic thing and really unlikely to change in a single generation. (Neither my default skin color - ghost white - nor my ability to tan - nil - is consistent with the latitude my parents grew up in.)

And then there are Siamese cats: We are Siamese if you Please, Alaska Science Forum. So I suppose if you ever found a snake with the "himalayan" mutation then yes, it would get darker in cold temperatures! But still not in quite the same way you were suggesting for parents having (permanently) lighter or darker offspring based on their environment.

Wow, thank you! That taught me a lot....I'm going to have to research melanin and skin/scale pigments now though. You've spiked my curiosity.

Oh and sort of a side-tangent - Does anybody know to what extent scales act like skin, aside from keeping insides from falling out. (any information would be appreciated).

[DrKate]

Does anybody know to what extent scales act like skin, aside from keeping insides from falling out.

Scales *are* skin. Reptiles skin is pretty much the same as ours, with all the same basic layers (dermis, epidermis, etc.). The scales are essentially compacted patches of skin - kind of like a whole bunch of little callouses, really. Not much happens within the scales themselves, but the soft skin in between has glands that make oils, stuff can get absorbed into that skin, etc., just like ours.

[GarterGeek]

Scales *are* skin. Reptiles skin is pretty much the same as ours, with all the same basic layers (dermis, epidermis, etc.). The scales are essentially compacted patches of skin - kind of like a whole bunch of little callouses, really. Not much happens within the scales themselves, but the soft skin in between has glands that make oils, stuff can get absorbed into that skin, etc., just like ours.

So, do the scales cover the skin or are they protrusions of the skin? If a scale fell off, what be underneath it - skin or muscle tissue? Am I correct in thinking that the purpose of scales is to act as an "armor"?

When a snake is taken into captivity, it's colors brighten after a while because it becomes cleaner and is no longer "absorbing" dirt. Snakes like to bask in the sun to "absorb" UV rays, and when a snake is exposed to excess humidity it gets blisters... Is it possible that snake skin absorbs stuff more readily than human skin? Would that make sense?

I hope I'm not bothering you with my questions. Your answers are really helpful and I appreciate it. Thank you.

[DrKate]

So, do the scales cover the skin or are they protrusions of the skin? If a scale fell off, what be underneath it - skin or muscle tissue?

I tried to find something with good pictures online, because I thought that might help, but I haven't been able to. Reptile scales are direct protrusions of the skin - the epidermis, to be specific. They are NOT like hairs, which periodically fall out and re-grow. Have you ever had a little tag of dead skin next to your fingernail, and you pull on it, and everything is fine until you start to pull on the deeper living skin layer where it's attached and suddenly it hurts like all get-out? That's what a snake scale is like. The dead protruding part is connected to the living epidermis and dermis underneath, and that's what would be exposed if you removed a scale completely. It's still skin (not muscle tissue), but deeper layers of the skin that are not supposed to be exposed to the outside.

Am I correct in thinking that the purpose of scales is to act as an "armor"?

Armor, a barrier against drying out, both traction *and* reduced friction for locomotion...

Is it possible that snake skin absorbs stuff more readily than human skin?

Keep in mind that your skin "absorbs" dirt too (ever worked on an engine and been embarrassed to go to a nice restaurant three days later because your hands were still dirty?). It's just that you shed your dead skin cells individually all the time, instead of saving them all up and peeling a whole layer off at once, so the change is less drastic. All in all snake skin probably absorbs most stuff *less* well than human skin, because the thick keratin layer of the scale is less permeable than our wimpy thin keratin.

I should have made a point about the "absorbing UV" thing earlier, but didn't catch it. When a snake is basking, what it's trying to absorb is not UV light but infrared light - heat waves! Like... moving closer to the campfire as the night gets chilly. UV rays are just as harmful to snake skin as to our skin - it's high-energy radiation that can get into cells and mess with DNA. Mess up the wrong bit of DNA and the cell goes crazy and becomes cancerous. It's true that dark pigments absorb more heat, and I honestly don't know if dark snakes are more efficient baskers than light ones. But really we have melanin as protection against UV radiation - because of its chemical structure it can absorb the high-energy ray and kind of dissipate it in a safe way. (The darkest-skinned people are from the places with the strongest sunlight, not the coldest temperatures!)

I hope I'm not bothering you with my questions.

Not at all! I like teaching biology, because people get such a kick out of learning how bodies work. Plus I figure more knowledge and less misinformation can only ever be good for the world.