mottling

Mottling refers to irregular patches of color or shading on a surface or tissue, resulting in a blotchy, speckled, or variegated appearance. The term is used across disciplines to describe patterns that lack uniformity, typically with edges that are irregular and a lack of a single dominant hue.

In biology, mottling often serves camouflage or signaling. Animal coats, feathers, and scales may display mottling from uneven pigment production during development, temperature-sensitive gene expression, or genetic variation. In plants, leaf mottling can arise from nutrient deficiency, viral infection, or environmental stress, sometimes aiding deterrence or camouflage.

In humans and animals, mottling describes patchy skin discoloration caused by vascular changes, cold exposure, or circulatory issues. Pathologists may use the term for irregular pigment distribution in tissues or for mottled appearances in organs, where the pattern reflects underlying conditions rather than decorative intent.

In geology, ceramics, food, and art, mottling denotes irregular, blotchy textures. Soils and rocks show mottling from redox-driven staining; glazes or surfaces can display mottled effects from layering, firing, or chemical reactions. In food, mottling can describe marbling or uneven coloration in dairy products, meats, or confections.