Answer: The typical pattern to markings shown by Siamese cats (and also by breeds such as Balinese, Birman and Himalayan) is due to regional variations in skin temperature, At the extremities of the cat’s body the skin temperature is normally slight lower temperature, the contain more of the dark pigment melanin and thus appear darker.
If part of the skin of the trunk is cooled more then usual, any new hairs which grow there will also be darker. This is seen around operation wounds and may be due partly to interference with the blood supply but more likely due to clipping of the exciting hairs which reduce insulation and increases heat loss in the area. Where Siamese cats are kept in very cold environments, the whole trunk will appear darker then usual. Conversely, in tropical countries, the normally dark extremities (known as ‘points’) are lighter then usual because they are warmer. The same effect, though localized, is seen when a dressing is kept on a limb for a long period; the increased warmth in the covered part causes new hairs growing there to be less heavily pigmented then those surrounding it.
