Interestingly, long-beaked common dolphins are never seen with a missing dorsal overlay. Instead they show a different mutation with somewhat similar results – which in turn is never observed in short-beaked commoners. If we may apply birding terms, these animals seem to be leucisitc. Leucism completely inhibits the production of melanins, resulting in a white animal. The eyes remain a normal colour. The common dolphin’s yellow patch however is likely produced by a different pigment (e.g. carotenoids as in birds), unaffected by leucism. As such, they retain the shape of their normal markings, but only the yellow is visible. Leucism need not be complete: sometimes regular-coloured patches remain, and leucistic long-beaked common dolphins often have these in the form of black spots on their back.
– Watercolour on hot-pressed paper, 14.8 x 21 cm (original available).