This article is from the Summer 1999 AFRMA Rat & Mouse Tales news-magazine.
Colors & Coats
By Nichole Royer
Q What is the difference between American Blue, English Blue, Russian Blue, Blue Agouti, Silver Blue, Powder Blue, and Sky Blue?
A There are so many different terms for Blues within the rat fancy that it is easy to get them confused. It does not help that in a number of cases there are multiple names representing the same color. Blue, English Blue, Slate Blue, American Blue, and Sky Blue are genetically all exactly the same thing. These are various names that different fanciers and organizations throughout the world have given to the same color. These rats are all a slate blue gray, often with a light undercoat. Due to the fact that this color can be selected for a lighter or darker shade, some of these designations have been given to represent the different shades. In England, the darkest shade of Blue has been selected for, where as many American fanciers have chosen the medium shade as their ideal. For this reason, the terms “English Blue” and “American Blue” have been used. AFRMA chose to follow England’s example and standardized the darkest shade of this color simply as “Blue”; however, many fanciers felt the medium shade was also very attractive and desirable so the term “Sky Blue” was developed to represent them. When discussing this kind of Blue in comparison to Russian Blue, the descriptive term “slate Blue” is often used.
The Russian Blue color is caused by a completely different gene from Blue. Instead of being a slate Blue, Russian Blue rats are a very deep, dark grey that could be mistaken for black in poor light. They do not have a light undercoat, and do not vary much in depth of color. Instead they can have a blue, gray, or brown tint to their coats. When Russian Blue and slate Blue (i.e. just plain “Blue”) are combined, you get a color called Silver Blue. This color consists of a coat in which half the hairs are light with blue tips. These are evenly interspersed with white hairs to give a silvered effect.
Powder Blue is an unstandardized color that is occasionally produced in “Blue” litters. Whether this very light blue is simply the lightest shade of the Blue spectrum, or whether it is caused by another color acting on Blue is yet to be determined.
Blue Agouti rats are exactly what their name implies. Blue acts on Agouti causing the black in the coat to become Blue and the red/brown to be diluted to a creamier color.
Shannon L. Nilsson, Jacksonville, OR
Q I am very interested in Blue Point Siamese; I would like to find a good trio to start with.
Obviously, some assistance in genetics would solve some of my problems. Do you know of any good sources? Can you tell me what good strains are easily bred from the Seal Points and Blue Points? As new mice strains are in high demand at pet stores, the more variety I can get from the two strains I would like to work with, the better.
A There are a number of fanciers in southern California who have very nice Blue Point Siamese. Many of them have done extensive crossing with English mice so their Siamese are very typey.
For the most part, the best other colors to produce out of a Seal Point and Blue Point Siamese line are Black Self and Blue Self. Other colors often will lighten/dilute the Siamese color or cause it to become sooty, so breeding other colors should be avoided. They can, however, be successfully produced in any of the coat types including Satin, Frizzie, Longhair, or any combination of the three.
Julianne Valentine, Lakewood, CA
Q I have a question about genetics. I am new to AFRMA and a new rat lover. I have two Blue rats (8 weeks old) and I plan on breeding them when they are old enough. I was told that one of their grandparents was a nude rat. Does that mean that there is a possibility that they could have nude or blotchy babies? What are the odds of them having Blue and or nude babies?
A Well, your odds of getting Blue rats are extremely good. In fact, any time you breed two Blue rats together you should get all Blue babies in the litter. That is of course unless they are also carrying other recessive genes as well.
The gene for hairlessness could well be one of those hidden recessive genes. Are your rats brother and sister? If so, and if they do both have a Hairless grandparent, then chances are 50/50 that each of your rats are carrying the gene for hairlessness. Both parents have to be carrying the gene in order for you to get Hairless babies. The only way to tell if they are carrying it is to breed them together.
On the other hand, if your rats are not brother and sister, and if only one of them has that hairless grandparent, you will not get any Hairless babies in your litter. Both parents have to carry it for you to see it.