Piebald

A piebald or pied animal is one that has a pattern of pigmented spots on an unpigmented (white) background of hair, feathers or scales. The spots are pigmented in shades of black and/or yellow as determined by the genotype controlling the color of the animal. The animal's skin underneath its coat may or may not be pigmented under the spots but the skin in the white background is not pigmented.

Location of the pigmented spots is dependent on the migration of melanoblasts (primordial pigment cells) from the neural crest to paired bilateral locations in the skin of the early embryo. The resulting pattern appears symmetrical only if melanoblasts migrate to both locations of a pair and proliferate to the same degree in both locations. The appearance of symmetry can be obliterated if the proliferation of the melanocytes (pigment cells) within the developing spots is so great that the sizes of the spots increase to the point that some of the spots merge, leaving only small areas of the white background among the spots and at the tips of the extremities.

Animals with this pattern may include horses, dogs, birds, cats, pigs, and cattle, as well as snakes such as the ball python. Some animals also exhibit colouration of the irises of the eye that match the surrounding skin (blue eyes for pink skin, brown for dark). The underlying genetic cause is related to a condition known as leucism.

In medieval English 'pied' indicated alternating contrasting colours making up the quarters of an item of costume or livery device in heraldry. Court jesters and minstrels are sometimes depicted in pied costume and this is the origin of the name of the Pied Piper of Hamelin.

The word "piebald" originates from a combination of "pie," from "magpie," and "bald", meaning "white patch" or spot. The reference is to the distinctive black-and white plumage of the magpie.

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