Python regius

Ball Python morphs and genetics

The most morph-driven species in herpetoculture, with four allelic complexes, two dominant genes that are lethal in their super form, and one sex-linked gene.

49 curated genes4 allelic loci2 lethal supers1 sex-linked

Working with ball python genetics

Ball pythons carry more named single-gene morphs than any other reptile in the hobby, and almost everything sold as a designer morph is a combination of the base genes below rather than a gene in its own right. Pastel Clown, Bumblebee and Killer Bee are combinations; Pastel, Clown and Spider are genes.

That distinction is what makes a real genetics engine worth having. A combination name tells you nothing about what a pairing will produce — the underlying genes do, and a ball python pairing routinely involves four or five loci at once.

What makes this species different

Ball pythons are where the simple textbook model breaks down, in four separate ways at once, and all four are modelled here: allelic complexes where two named morphs sit at the same locus and can never be inherited independently, super forms that are lethal, a gene whose inheritance depends on the offspring's sex, and compound hets that look like a morph rather than a carrier.

Allelic groups

Genes in the same group share a locus, so an animal has only two slots between them — they can never be inherited independently or stacked as separate supers.

  • Toffee · Candy
  • Lesser · Butter
  • Cinnamon · Black Pastel · Mocha
  • Phantom · Mystic

How allelic series and compound hets work

Lethal in the super form

Spider and Champagne are not viable with two copies. Breeding two of the same together loses roughly a quarter of the clutch before hatching, and the odds among the animals that do hatch are renormalised — about two-thirds visual rather than three-quarters.

Read more on lethal super forms

Sex-linked inheritance

Banana sits on the Z chromosome, so which parent carries it decides the sex ratio of the offspring that inherit it. Results are split by sex rather than given as one figure.

Every curated ball python gene

Grouped by mode of inheritance. This is the dataset the HerpSync calculator runs on, published in full — the flags in the last column are what a standard Punnett square gets wrong.

Recessive (17)

Two copies to show

Needs a copy from each parent to be visible. One copy makes a het — an animal that looks normal and carries the gene.

  • Albino

    Lacks melanin — yellow & white. Also called: Amelanistic.

  • Axanthic

    Lacks yellow/red pigment — black & white. (Multiple non-allelic lines.)

  • CandyAllelic

    Allelic with Toffee.

  • Caramel Albino

    Caramel-toned tyrosinase-positive albino.

  • Clown

    Reduced/striped dorsal pattern.

  • Desert Ghost

    Distinct hypo line; high gold. Also called: DG.

  • Genetic Stripe

    Continuous dorsal stripe.

  • Ghost

    Reduced melanin — washed-out look. Also called: Hypo, Hypomelanism.

  • Lavender Albino

    Albino with lavender background.

  • Leopard

    Broken, spotted pattern.

  • Monsoon

    Pattern-scrambling recessive.

  • Piebald

    Patches of unpigmented white. Also called: Pied.

  • Rainbow

    Iridescent pattern recessive.

  • Sunset

    Deep red-brown recessive.

  • ToffeeAllelic

    Light recessive; allelic with Candy. Also called: Candino base.

  • Tri-Stripe

    Three-striped recessive pattern.

  • Ultramel

    Intermediate hypo/amel.

One copy changes the animal's appearance; two copies produce a distinct, usually more extreme super form with its own name.

  • Asphalt

    Super form: Super Asphalt

    Yellow-belly-complex; darkens.

  • Bamboo

    Super form: Super Bamboo

    Super is blue-eyed leucistic.

  • BananaSex-linked

    Super form: Super Banana

    Sex-linked; a female Banana throws mostly male Bananas. Also called: Coral Glow.

  • Black PastelAllelic

    Super form: Super Black Pastel

    Allelic with Cinnamon/Mocha.

  • ButterAllelic

    Super form: Super Butter

    BEL-complex; allelic with Lesser.

  • Calico

    Super form: Super Calico

    White flecking/markers.

  • Chocolate

    Super form: Super Chocolate

    Rich brown base.

  • CinnamonAllelic

    Super form: Super Cinnamon

    Dark brown; super is near-black. Allelic with Black Pastel/Mocha.

  • Enchi

    Super form: Super Enchi

    Adds orange tones.

  • Fire

    Super form: Super Fire

    Super Fire is a black-eyed leucistic.

  • GHI

    Super form: Super GHI

    Darkens; high gold. Also called: Gotta Have It.

  • Granite

    Super form: Super Granite

    Speckled pattern modifier.

  • Gravel

    Super form: Super Gravel

    Yellow-belly-complex marker gene.

  • LesserAllelic

    Super form: Super Lesser

    BEL-complex; super is leucistic. Allelic with Butter. Also called: Lesser Platinum.

  • MochaAllelic

    Super form: Super Mocha

    Allelic with Cinnamon/Black Pastel.

  • Mojave

    Super form: Super Mojave

    Super is a blue-eyed leucistic (BEL).

  • MysticAllelic

    Super form: Super Mystic

    Allelic with Phantom.

  • Pastel

    Super form: Super Pastel

    Brightens color; super is high-contrast.

  • PhantomAllelic

    Super form: Super Phantom

    Muted pattern; allelic with Mystic.

  • Russo

    Super form: Super Russo

    BEL-complex.

  • Special

    Super form: Super Special

    BEL-complex leucistic super.

  • Spotnose

    Super form: Super Spotnose

    Altered head/nose stamp.

  • Sulfur

    Super form: Super Sulfur

    High-contrast yellow.

  • Vanilla

    Super form: Super Vanilla

    Brightening; BEL-complex.

  • Yellow Belly

    Super form: Ivory

    Super form is Ivory.

One copy is enough to see the trait, and two copies look no different from one — so there is no super form to breed for.

  • ChampagneLethal super

    Reduced pattern; the homozygous 'super' is lethal.

  • Disco

    Pattern aberrancy.

  • Hidden Gene Woma

    Pattern-reducing; super often lethal. Also called: HGW.

  • Pinstripe

    Reduced pattern with thin dorsal lines.

  • Sable

    Darkened dorsal striping.

  • SpiderLethal super

    Thin pattern; associated wobble. No viable homozygous.

  • Woma

    Reduced, banded pattern.

Breeding and incubation

Eggs are typically incubated around 30–32°C for roughly 60 days, and females are usually bred at three years rather than at first ovulation — size and body condition matter far more than age. Clutches are small enough that per-clutch record keeping is realistic, which is exactly where predicted odds and actual outcomes start to diverge in interesting ways.

Scientific name
Python regius
Group
Pythons
Reproduction
Egg-laying
Incubation
~60 days
Maturity
~37 months
Young are called
Hatchlings in a clutch

Timings are husbandry-typical approximations used for projections and reminders, not veterinary scheduling. Every figure can be adjusted per workspace.

Try a pairing

Pick genes for two ball python parents and see the full odds — per gene and per combination — with no account and nothing to install.

Ball Python morph calculatorAll species

Common questions

What is the difference between a ball python morph and a gene?

A gene is a single inherited mutation, like Pastel or Clown. A morph name sold at an expo is usually a combination of several genes — a Bumblebee is Pastel plus Spider. Only the genes are inherited; the combination name is just what breeders call that particular set.

Why can't I breed a Super Spider?

Spider is lethal in its homozygous form — an embryo that inherits two copies is not viable. Spider bred to Spider therefore produces roughly two-thirds Spider and one-third normal among the animals that hatch, not the 25/50/25 a Punnett square predicts. Champagne behaves the same way.

Why does Banana produce mostly males from some pairings?

Banana is sex-linked. Depending on which parent carries it, a pairing can throw predominantly male or predominantly female Bananas — the well-known male-maker and female-maker lines. A calculator that treats it as an ordinary co-dominant gene gets the sex ratio wrong.

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