A smooth coated guinea pig of all one colour is known as a Self. They come in a multitude of colours, black, red, cream, white, golden, lilac, chocolate to name a few. Each colour is referred to as a separate breed, and within each colour they may also be identified by their eye colour, e.g. the pink-eyed white, and the dark-eyed white. However there is interbreeding between the colours due to the genetics of the colour genes, e.g. A buff * white mating will produce all creams, whereas a cream * cream mating will produce 50% cream, 25% buff and 25% white! The top colour is an even shade across the body, with the under colour slightly paler. All Selfs have flat faces with broad roman noses.