We currently have the following coat types in Australia;
The coat is short and sleek, with longer guard hairs.
Rex – Rere
The coat and whiskers are wavy. This is much more noticeable when young, with the fur often becoming straighter as the rat matures. The rex gene is co-dominant.
Double Rex – ReRe
The coat and whiskers are tightly curled. Generally a double rex will moult part or all of its fur at around 6 weeks of age. The fur grows back in tight curls. The rex gene is co-dominant.
Patchwork rex have a coat that moults and regrows in patches for the entire of their lives. This can result in some pretty funky looking hairstyles! It is unknown how this trait is inherited as yet. It is most likely to occur in double rex rats, but has sometimes occurs in single rex rats, to a lesser extent.
The coat is much longer than the standard coat. Unlike the silk coat it is no shinier than a standard coat, and unlike the carasilk coat each hair lies flat and does not sit in clumps. It is a co-dominant gene.
Both of these coat types are very similar to each other. The silk coat is smooth and very soft, has an iridescent sheen and appears like velvet under glass. Most silk rats have guard hairs, approximately 10% do not. This is especially noticed on males, who stay soft throughout their lives with no guard hairs. It is a co-dominant gene.
The Carasilk coat appears as though wet/greasy, and separates in clumps rather than laying flat and smooth as per the silk coat. A Carasilk rat does not have guard hairs. It is a co-dominant gene.
These two coat types have recently emerged in Australia and are not standardised. The velour coat looks identical to rex and the powderpuff identical to silky in photographs, we have not seen either of these coat types first hand. Both genes are reportedly recessive, which would suggest that they are different to both the rex and silky genes which are co-dominant.