Compared with mice, there are relatively few color forms of the Fancy Rat. They can be divided into two groups: the basic colors and the recognized pattern markings.
Rats are, certainly, among the most popular varieties with the pet owner - possibly because they appear clean! There is a Pink-eyed White, which is also known as the Albino. Young rats of this variety tend to become creamy in color as they get older. There is also a distinct Self Cream strain.
Most of the colors developed in mice are also seen in rats. The Agouti most closely resembles the ancestral Brown Rat, but the depth of brown coloration has been increased, becoming richer overall. A Silver counterpart, known as the Silver Fawn, has silver guard hairs set against a rich orange fur. The pink-eyed mutation here again exerts a diluting effect on overall body coloration. The Cinnamon mutation has an intermediate effect, creating a russet-brown shade of coat color with longer chocolate guard hairs.
Among the darker colors, Self Blacks (ideally as deep as possible) and Self Chocolate (showing no trace of white) have been developed. Other varieties corresponding to the colors seen in mice are the Champagne and the Pearl, the latter being one of the more recent innovations. A color unique to rats is the Self Mink. Ideally, these rats are coffee colored, with a bluish tint and black eyes. They are, in effect, a dilute form of the Self Chocolate.
Undoubtedly the most widely seen of the patterned varieties is the Hooded Rat. The so-called hood extends from the top of the head to the face and down to the shoulders and chin. Another colored area, the saddle, extends down the back and on to the tail. While any color is acceptable to form the hood and saddle, the remainder of the body should be white. It is not easy to produce a top exhibition specimen of this variety. A more straightforward version is the Capped, which simply lacks the saddle but retains the colored head. Another similar variety is the Variegated, which differs from the Capped in having a mixed rather than a white body color, although the belly itself must remain white.
A white belly is also characteristic of the Berkshire, which should also show white feet and a similar spot on the forehead. The remainder of the body is colored. Irish rats, by comparison, are more highly colored, with a white area forming a small equilateral triangle on the chest. White is otherwise restricted to the feet. in France, notably the Himalayan form, which was first seen around 1972. The points are darker than the body coloration, creating an attractive contrast. It does not differ significantly from the identical mutations seen in other animals, including mice and rabbits. The Himalayan itself is predominantly white in color, whereas in the Siamese the fur is pale brown. The pairing of Himalayans together should yield on average two Himalayans for every one Siamese and one Albino. Thus, a quarter of the litters should be Siamese.
Article Source: http://EzineArticles.com/?expert=Derrick_R_Anderson