Well, most info you will find on the net for them is VERY general, and usually applies to "most" of the triangulum complex at best. But yes, the Andean milksnake's care is MUCH like that of L.t.gaigeae. They are both a montane form in the highlands of their ranges, and the Andean has been found as high as 9,000 feet in elevation. They thrive in slightly cooler temps than do many other milksnakes. They do best with a fairly high humidity and temps in the lower to mid 70's, although a small warmer spot in the enclosure of the low 80's is good for them to thermoregulate as needed. They do not do well with ambient static temps in the 80's.
The "Inca" phase are basically slightly aberrant patterned animals that tend to have some random, broken and/or incomplete staggered ring triads here and there, and also can have more orange inner light rings than the more typical forms of andesiana does in the hobby.
I'm not exactly sure of the inheritability though, but I'm pretty sure it is not 100% predictable like a recessive trait would be, or even a co-dom per se where you would expect half to be incas and half to be normal if one was bred to a normal phenotype animal. I believe it is more like if you bred a tangerine Hondo to a tricolor, and you could get either types as well as intermediates too. Maybe someone that has bred them personally could also chime in on that too. I know Shannon Brown has bred them in the past.
Also, certain lines of "Inca" hatchlings tend to look normally colored, and as they mature they develop more orange.
Here is a really nice example of a well-patterned "Inca" phase Andean off the net, as well as a normal I owned many years ago in the mid 90's
~Doug


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"a snake in the grass is a GOOD thing" 

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