First published August 3, 2026.
No part of this article including text and photos may be reproduced without explicit written permission.
No part of this article including text and photos may be reproduced without explicit written permission.
Since early 2016, I have been working with a group of adult Anza Borrego rosy boas. I purchased the group without having been provided with detailed information about how each was related.
In 2022, I produced from that group an unusual rosy boa in an otherwise normal litter of five. This snake has very reduced orange striping, which causes the base blue tone to look more silver simply through reduced visual contrast compared to typically colored rosies of this locale, along with an overall pastel tone. The first photo below was taken prior to first shed, but this snake continues to be fairly similar in appearance regardless of whether in shed or not.
In 2022, I produced from that group an unusual rosy boa in an otherwise normal litter of five. This snake has very reduced orange striping, which causes the base blue tone to look more silver simply through reduced visual contrast compared to typically colored rosies of this locale, along with an overall pastel tone. The first photo below was taken prior to first shed, but this snake continues to be fairly similar in appearance regardless of whether in shed or not.
The eye has a silver iris that takes on a sky blue cast when viewed in relation to the whole snake.
For comparison, here is a littermate of the rosy pictured above, with the typical bold orange pattern that draws out the blue in the base tone. The eyes of all the normal littermates have the typical brownish orange iris:
Here’s that unusual rosy at one year of age. She has retained the silvery-blue iris, and the body color has shifted a bit but not to anything typical or expected from this locale.
Since then, I have produced a few more that are visually similar to the first. This morph is apparently a simple recessive gene. I’ve identified the heterozygous carriers in my collection both by test breeding and tracing ancestry in my breeders, and the visual offspring ratios are as would be expected (approximately 25% of offspring from assumed het pairings)
What the gene is, is a different matter. It might be thought possibly to have been crossed in to my Anza Borrego stock, though I’m assured by the producer of that stock — Giovanni Fagioli — that they’re pure Anza Borrego. But there’s always the possibility that escaped or released stock in that locale could have provided the gene, similarly to speculations regarding Borrego albino. If that’s the case (or even if it isn’t), a look to existing genes might be fruitful.
I’ve test bred a homozygous (visual) example against a visual Coastal anerythristic, in order to determine if this gene is one of the existing anerys or allelic with that complex. All offspring were clearly visually normal. This is a photo at birth of one of this uniformly appearing litter, along with a partial view of the mother for comparison.
Here are the possibilities from currently identified genes.
Coastal anerythristic
It is not Coastal anery, by test breeding and also according to description at https://www.rosyboamorphs.com/coastal-anerythristic.
“The Anerythristic Coastal exhibits a grey-silver background color with slightly darker jagged striping and high degree of dark speckling attributable to the Coastals normal pattern influence. Eye color is dark grey.”
Both the body color, particularly the darker stripes, and eye color are not consistent.
“The Anerythristic Coastal exhibits a grey-silver background color with slightly darker jagged striping and high degree of dark speckling attributable to the Coastals normal pattern influence. Eye color is dark grey.”
Both the body color, particularly the darker stripes, and eye color are not consistent.
Borrego anerythristic
This is not Borrego anery. According to https://www.rosyboamorphs.com/borrego-anerythristic :
“As neonates, the Anery Borrego line rosys appear only slightly darker in overall body color to their normal wild type siblings. Eye color on the newborns is usually the give away, as it is very dark in comparison. “
This seems to be the opposite (darker body, darker eye) of the above unusual rosy.
Also, Borrego anery is compatible with Coastal anery so would have proven out in test breeding.
“As neonates, the Anery Borrego line rosys appear only slightly darker in overall body color to their normal wild type siblings. Eye color on the newborns is usually the give away, as it is very dark in comparison. “
This seems to be the opposite (darker body, darker eye) of the above unusual rosy.
Also, Borrego anery is compatible with Coastal anery so would have proven out in test breeding.
Pioneertown anerythristic
This looks a lot like Pioneertown anery. At https://www.rosyboamorphs.com/pioneertown-anerythristic ,
“The Pioneertown Anery exhibits a light grey-silver background color. It's fairly straight striping retains a slight brownish purple hue. Its eyes exhibit a dramatic looking light blue iris with a black pupil.”
But, according to https://www.rosyboamorphs.com/copy-of-smith-snow, “the Pioneertown and Coastal Anery genes are compatible”.If this were Pioneertown anery, it would have proven out in test breeding with the existing anery gene complex.
Morongo Valley axanthic
Morongo axanthic is not compatible with the existing anery complex, so is a possibility. But visually, this clearly is not Morongo axanthic, according to the description at https://www.rosyboamorphs.com/morongo-basin-axanthic :
“The Anerythristic Morongo Valley presents an extremely unique genetic color expression with purplish-grey jagged stripes overlaying a very light grey, blacked flecked background. Its eyes appear black.”
Neither the body color and eye color are a match.
“The Anerythristic Morongo Valley presents an extremely unique genetic color expression with purplish-grey jagged stripes overlaying a very light grey, blacked flecked background. Its eyes appear black.”
Neither the body color and eye color are a match.
This is a new anerythristic gene in Lichanura orcutti
This unusual rosy appears to possess an anerythristic gene that is not part of the current known anery complex. I’ve decided to call the gene ‘Silver’, and a pure locale rosy with the gene a ‘Silver Anza’, based on the base color and also short for ‘Silver Apple Anza Borrego’.
I have not yet experimented with combinations of this gene and other existing genes. Combination with Borrego albino could produce a locale-specific snow. Combination with one of the anerys in the Coastal complex would be a fascinating possibility.
-- John Zillmer, Silver Apple Exotics
The most recent update to this article took place on August 3, 2026.