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English: Depending on the horse's breed, genetics, hormonal activity, diet, environment etc. its black pigment can bleach in sunlight considerably. Bleaching eumelanistic horses have not been proven to be genetically different from non-bleaching ones in horses (yet), but some registries (most famously the Icelandic registry) differentiates between "staying" blacks and bleaching ones. In black specifically, major bleaching can be caused by an otherwise cryptic Cream factor, but this is not always the case.