mottle

Mottle refers to a pattern consisting of irregular patches or blotches of color that differ from the surrounding area. The term is used across disciplines to describe similar appearances whether on living tissues, plants, or non-living surfaces. It can describe both a pattern and the process by which it is produced.

In biology, mottling often describes coloration in animal skin, fur, scales, or feathers. It may result from the uneven distribution of pigment cells (melanocytes), from genetic variation, or from adaptive camouflage. Examples include mottled horses, certain gecko species with irregular blotches, and birds with mottled plumage. In plants, mottling describes leaves that show irregular green and yellow or lighter patches; causes include nutrient deficiencies, viral infections (such as mosaic viruses), or genetic variegation. In medicine, skin mottling is a clinical sign of patchy pallor and redness that can indicate altered blood flow or perfusion.

In textiles and materials, mottling refers to an intentionally irregular coloration produced by dyeing, printing, or finishing techniques, or to leather with a speckled two-tone appearance. Mottled patterns are used for camouflage, texture, or aesthetic effect. The concept is related to, but distinct from, patterns such as speckling, variegation, or marbling, though overlaps can occur in practice.

Overall, mottling describes a broad class of irregular, patchy appearances encountered in nature and human-made materials, spanning aesthetic, diagnostic, and functional contexts.