Ball pythons are a popular pet for snake buffs because they do not attain a great size, like some other snakes, and are not aggressive. Breeders of this species have produced hundreds of genetic color and pattern variations, called morphs. An axanthic ball python is a morph, or genetic mutation, that lacks either red or yellow pigments or both. This results in a snake with a black and grey color scheme. The gray color can vary in shade and can range from almost white to a silvery blue-gray, even on the same animal.
A typical ball python has rich brown patches on a black background. These patches are often outlined in a pale yellow or tan color. An axanthic ball python lacks the genes necessary to produce the yellow and red pigments that result in the yellow and brown colors and almost looks like a black and white photo of a normal python. Some axanthic ball pythons may lack only the yellow pigment. These are known as red axanthic ball pythons.
When they are first born, the black and gray pattern of an axanthic ball python is often very striking, but the intensity of these colors can fade somewhat as the snakes age. Some snakes may also exhibit a phenomenon that breeders call "browning out." This refers to a gradual appearance of a slight brown coloration on the gray areas of the snake. It occurs mostly on red axanthic ball pythons, and some breeding lines are known to hold their colors better as they age.
Since the mutation that produces an axanthic ball python is a color mutation, the pattern on such a snake will resemble a typical python pattern. The patches of gray will begin at the base of the sides of the snake and extend upwards. These patches will be irregular and varied in shape and may occasionally run together. Black spots are often present within the patches of lighter color as well, sometimes in pairs.
Breeders and collectors are interested in axanthic ball pythons because of their usefulness in producing other morphs. They can be bred to each other to produce a morph called a snowball python, which is bright white with pink eyes. Breeders also use axanthic ball pythons to try to breed out the yellow colors from existing morphs as well as to create new morphs.