When Siamese is used without any qualification, this normally refers to the “classic” seal point, red eyed Siamese. A good Siamese is one of the great beauties of the rat world, with deep sepia points shading into a warm beige body colour, set off with rich ruby eyes.

The gene responsible for Siamese rats is temperature sensitive, which accounts for the colour being darker on the extremities of the rat, but selective breeding is also very important in getting the shading as dark as possible. The temperature sensitive nature of the colour means that they’re prone to particularly odd moult marks and lines when new fur grows in. They also tend to be darker when kept in cold temperatures, (or during the winter) and paler when kept in the warm (or during the summer).

As well as ruby eyes, Siamese can also be bred with black eyes. The black eyed varieties are superficially identical to the ruby eyed version, but the overall colour tends to be creamier and warmer due to the influence of the black eyed gene.

Genetics: Non-agouti with two copies of the Himalayan gene (aachch), or non-agouti with two copies of the Himalayan gene plus at least one copy of the black eyed gene (aaBe-chch) for the black eyed version.

NFRS standard: Body colour to medium beige, gradually and evenly shaded over saddle and hindquarters towards the belly, being darkest at the base of the tail. There should be no white or very pale areas anywhere on the body, feet or tail. Tail colour to extend down the length of the tail. Belly to be light beige. Points to be rich dark sepia and shade evenly into the body colour. Eyes black or ruby.