All Angles Creatures

Anerythristic Type I Red-Tailed Boa Constrictor

breeder consensusrecessive

Red and orange pigment absent, leaving a grey, brown and black animal.

How it inherits

One copy
One copy shows nothing at all. The animal looks ordinary and is called a carrier, or “het”.
Two copies
Two copies, one from each parent, are needed before it appears.

Anerythristic Type I carrier × Anerythristic Type I carrier

Four ways the two can meet.

1 in 4het Anerythristic Type I
1 in 4het Anerythristic Type I
1 in 4Anerythristic Type I
1 in 4Normal
  • het Anerythristic Type I50%
  • Anerythristic Type I25%
  • Normal25%

A pale box is an animal that shows the morph. These are the odds for each egg on its own, not a promise about a clutch.

Worth knowing. As with the albinos, there is more than one anerythristic line. Type I and Type II are different genes and pairing them produces no anerythristic young.

What this rests on

Established by breeders through repeated crosses and recorded in community documentation, not by published genetics. That is how almost all morph inheritance is known — and it is worth saying rather than presenting it as laboratory fact.

What happens if you breed it

Every pairing involving Anerythristic Type I, worked out gene by gene — including what the clutch can be and anything documented about the animals it produces.

See every Red-Tailed Boa Constrictor pairing

Other Red-Tailed Boa Constrictor morphs