When is blue not really blue?

[ConcinusMan]

It´s easy to see how lacking of one pigment is changing colours, when you´ve learned that almost all colours on a snake are mixtures of black(blue), red and yellow pigments.

Also since different pigments can be a different levels in the skin, results of certain colors being absent can have surprising results. In the case of chromatophores, the usual rules of red + yellow = orange and yellow + blue = green do not necessarily apply, especially when another unseen pigment is revealed by removing just one other pigment. I guess what I'm getting at is that green frogs aren't really green, and I don't think my blue snakes are really blue. It's an illusion.

"The green color typical of many frogs is created by yellow pigment layered over gray cells, which in turn makes the frog look green to human eyes. In some cases, the yellow pigment is missing. And due to this genetic abnormality, the frog appears blue."

There is no blue pigment! ^^^. The frog only appears blue because some other pigment is missing. I think that's what's going on with my blue anery concinnus. I have discovered that when very cold (brumating) the blue coloration of my snakes disappears. When warmed back up, they first appear greenish, and only when they are very warm, do they appear blue. Also, the light source has a great influence on how blue they appear. Interesting. Read this:

Rare Blue Frog Struts its Stuff at NHM - Humboldt State Now

I think something similar is going on here with these T.s. concinnus'. I believe there is no blue pigment, there is only the lack of some other pigment.



(also see my avatar)

[Stefan-A]

Blue: Wavelength 440–490 nm.

[ConcinusMan]

Good info. That brings up another point. Sometimes even with the lack of any blue light hitting them, chromatophores in the skin can actually alter the wavelength of light before reflecting them back and so, you can see blue even though no blue light was present before it got reflected back. Iridescence (the rainbow colors we sometimes see on a black snake) is a good example.

[ConcinusMan]

Wait. Allow me to correct myself. Iridescence is when the various wavelengths of light are not altered, but instead reflected back at different angles. What I'm saying about the blue is let's say, green light hits pigments in the skin and the wavelength itself is what gets altered, not the angle of reflection. Temperature of the snake can have an influence on how much the wavelength gets altered. I think this is why my snakes never appear blue when they are cold.

[gregmonsta]

The lacking of a certain pigment could be possible ... or a combination of both. As I mentioned before Xena's skin shows a blue dorsal stripe where as it was lime green while on her body.
There could be a difference between underlying pigments subcutaeneously as well.

[Steven@HumboldtHerps]

My understanding is that Pacific Chorus Frogs have 3 layers of chromatophores: Closest to the surface are the xanthophores (yellow), in the middle iridiophores (reflect blue!), and deepest are the melanophores (duh!) Yes, the mutation appears to be in the xanthophores. I need to find the source for this info again, but if it's accurate, that would mean "blue + yellow = green" like we normally perceive it. Of course, I am not implying that other stuff is not involved in other species (like the blues in garters.)

I am always fascinated by the variations in Pseudacris, here locally either regilla or sierra (not known yet.) I am not sure if they are in abundance of red pigments, but I have seen these frogs with orange trim (assuming that color equation.) Also, the ability to change from green to brown and back in some individuals, pattern variability, and color changes with age all make the mystery more complex.

I have seen this blue frog in person!

[ConcinusMan]

Awesome! I would love to see it myself. From a very early age, moving from WA to San Diego and back, and living in various locations in CA, I too noticed the wide variation of color in those frogs. I was completely shocked when I first got to San Diego and found the frogs living in canyon bottom. All the frogs there were metallic gold, metallic silver, or metallic bronze. I mean, they looked like metal. There were also a few like you mentioned that looked mottled with varying shades of brown but if I placed them in greenery for a while, large portions of their bodies would turn military green. The environment they lived in was dead and brown much of the year, but in late winter-early spring during the rainy season, the area would turn very green leaving any brown frogs at a disadvantage. The ability to change from brown to green and back must have been very necessary in a place like that. The metallic one's were usually not found out and about in vegetation. I'd always find those hunkered down in muddy banks. There was a lot of varying colored clay in the soil so they blended right in.

I have considered that the reason for the blue in these snakes is that they are actually axanthic. I mean, it could be that the orange (almost red) spots on their sides get their color from xanthophores since I read that they are not always yellow. Take that away and you get the blue. A blue glow or tint has been seen in other axanthic snakes.


Still, some of the anerys I find aren't blue and those definitely have yellow in their stripes but their spots are pure white.

[zooplan]

I have considered that the reason for the blue in these snakes is that they are actually axanthic. I mean, it could be that the orange (almost red) spots on their sides get their color from xanthophores since I read that they are not always yellow. Take that away and you get the blue. A blue glow or tint has been seen in other axanthic snakes.

You considered wrong, although there must be no yellow or green in the pattern.

Still, some of the anerys I find aren't blue and those definitely have yellow in their stripes but their spots are pure white.

There are three kinds of rules (genes) respossible for the pattern:
1. density and distribution of chromatophores.
2. size of chromatophores.
3. colour synthesis.

The lableling should be:
xanthic, hyperxanthic, normal, hypoxanthic, axanthic
for
only yello, more yellow, common, less yellow, no yellow

This labeling system does not give any hint if the difference is based on a change in a rule of typ 1,2 or 3.
I don´t know if there´s been any study on any morph.

Some of the "facts" about colour morphs are transfered from mammal studies, that can´t fit for reptiles.

A human redhead is a hyperxanthic yellow haired, thats a fact.

Reptiles have three kinds of chromatophores and three kinds of clolours,
mammals have only two!

[ConcinusMan]

Thank you very much! I like to throw ideas out there especially when I know I'm probably wrong. What pleases me even more is when somebody speaks up and tells me so!

Your response is what I've been fishing for Udo.

I need clarification though. When you say "there must be no yellow or green in the pattern" are you referring to axanthic in reptiles/amphibians?

I'm also confused about the human reference. I happen to have been born with some genetic quirks myself. All through my childhood my hair was the color of a new copper penny. As teen, my hair was mostly blonde. To this day, I still sunburn in about 30 minutes give or take, depending on latitude and time of year. My mustache and beard are still very red, and I still freckle. You said that redhead is yellow haired and that's what confuses me. Don't even get me started on my eyes. My eye color is hazel, but they sometimes look very blue. (Co-dominant inheritance, blue eyes, brown eyes)

I hear that red hair is an endangered genetic trait these days, as are green eyes. Both being recessive.

Are saying I'm hyperxanthic? What did you call me?



In spite of all this, both my parents are half native American. One is half Cherokee, the other is half Blackfoot. I inherited my red hair and fair skin from my father's mother I guess. She was a red haired fair skinned woman. My father is dark hair, dark skin, tans easily like his father.

So now this has turned into, "when is red hair fair skin, hazel eyes, a person with native American blood?"

But seriously, I want to learn more about the snakes and me.

[Steven@HumboldtHerps]

Awesome! I would love to see it myself. From a very early age, moving from WA to San Diego and back, and living in various locations in CA, I too noticed the wide variation of color in those frogs. I was completely shocked when I first got to San Diego and found the frogs living in canyon bottom. All the frogs there were metallic gold, metallic silver, or metallic bronze. I mean, they looked like metal. There were also a few like you mentioned that looked mottled with varying shades of brown but if I placed them in greenery for a while, large portions of their bodies would turn military green. The environment they lived in was dead and brown much of the year, but in late winter-early spring during the rainy season, the area would turn very green leaving any brown frogs at a disadvantage. The ability to change from brown to green and back must have been very necessary in a place like that. The metallic one's were usually not found out and about in vegetation. I'd always find those hunkered down in muddy banks. There was a lot of varying colored clay in the soil so they blended right in.

There was a study done on the ability of Pseudacris regilla's color-changing abilities, where they stuck the frogs in white-wall enclosures as well as ones with different shades/hues of greens and browns. Then they shone varying wavelengths of light upon them and monitored the frogs' color changes over time. The study noted complete changes from green to brown and back at specific wavelengths, some transitions taking days, even weeks. Not all frogs however changed color. I personally have noticed the changed in less than a day in my outside tanks, where they feel at home and get real sun.

I am sorry I don't have the study at hand, or even what it was called, but the study additionally confirmed that while most all of these frogs have the ability to lighten and darken (just like a basking blue-belly fencie going dark,) only a portion of the gene pool displays phenotypically observable total color changing abilities (green to brown, etc.) The rest are typically either green or brown; grays, olives, and tans exist as well but are less common. It has been noted that while the browns and greens can lighten and darken, they will always be either brown or green. The color-changers, while being able to swap greens and browns, usually can't achieve the bold examples of either colors found in the non-changers. Add to this that these guys can be bi-colored (brown and green - usually with a pattern), then add the metallic sheens of copper, silver, bronze, and gold (a phenomenon I have witnessed with juvenile frogs as well as with basking adults - I think basking may play a role with metallics, as they come and go like the weather) well, it all just beckons more research!

What has been discovered is that populations of Pseudacris throughout California commonly have this 3-way ability to be either green, brown, or changeable, and that this strategy helps any such population to endure fluctuating seasonal weather patterns. Easy to see how browns might be better camouflaged in a dry year and so forth...

That means there's a unique mix of genes in these pools that all the variants probably carry. One of my questions is: Is it random genetics at play here, or does there exist a biological mechanism to detect changing weather conditions which can turn some switches on and off, so as to prepare for a more appropriate color. Might be a long-term study with multiple sites. Perhaps during a wet year there was a hypothetical population crash because not enough greens were produced. That might then negate any color preparation, proving randomness. I just don't think it's all so random. Nature's always more infinitely complex than our own assumptions and usually our own discoveries as well.

And now it's not just P. regilla anymore. Pacific Chorus Frogs have been newly divided into 3 separate species: P. regilla (Northern Pacific,) P. sierra (Sierran,) and P. hypochondriaca (Baja CA.)

How does all this relate to garter snakes? (since this is all about frogs...) Well, I can't say I know exactly how a garter sees, but I do know, being primarily diurnal, they probably can see a lot better than many other snakes. ...And as we all know, snakes have excellent blind sight. Their motion detection is incredible!

It all about not being seen! On that note, I recommend everyone look up Monty Python's "How not to be seen" on YouTube.

Steve