American Fancy Rat & Mouse Association

This article is from the Winter 2001 AFRMA Rat & Mouse Tales news-magazine.

Breeding – Beyond the Basics: The Breeding Chart

By Nichole Royer

The Dilemma. We want to breed this rat, Tarot’s Simple Snazzy, to one of the females below. Which shall it be?
Female X
Female X
Female Y
Female Y
Femail Z
Female Z

Breeding rats and mice is fairly simple. If you want to produce some babies, you simply put together a male and a female rat or mouse who are each healthy and have nice temperaments. Barring unusual complications, in about 3 weeks you should have a litter of nice pets. Setting aside any ethical concerns, it's a fairly straightforward process.

Breeding fancy rats and mice is another matter entirely. Here the goal is to produce animals that are not just friendly and healthy, but also are pleasing to the eye. These breeders strive to produce animals that have to have proportional bodies, nice color, good markings, and who come as close as possible to matching the fancier's interpretation of the written standard for that variety.

This kind of breeding is every bit as much an art form as it is a science. Some of these folks breed with intent to show, and others breed just for their own personal pleasure. In both cases, the fancier gets enormous enjoyment and takes much pride in producing an animal that is not just a pet, but that is a good representative of its variety as well.

This all makes choosing breeding rats and mice much more difficult. Responsible breeders breed with the goal of always producing babies that are an improvement on their parents. This means that the decision of what animal to breed to which has to be a carefully thought out one.

The decision of which animals to breed together can be a difficult one. Often, folks simply breed their rats and mice to whatever mate they have on hand. While this can work out fine, often the handiest combination isn't the best.

I have found a system that is very helpful in making it clear to me what I am looking at in each animal I'm considering for breeding. This system involves putting together a simple chart for each breeding I'm planning.

The chart I use is one I created to meet my specific needs. It includes all the characteristics that are important to me. The number of points I assign to each characteristic are dependent upon how important I feel that characteristic is. I leave several blank spaces for features that are unique to a specific breeding, and use them or not as needed.

Each breeder is going to have specific characteristics that are more or less important to them in their specific breeding program. Also, each variety, color, and marking is different and has its own unique characteristics. My chart works well for breeding my Siamese rats, but of course others will have a different set of priorities. I'll give an example here but remember, it is just a guide.

I like to start by evaluating the animal I would like to breed, be it a male or a female. I find it helpful to begin by filling out column A of the chart on the next page. This gives me a clear picture of my rat's good points and bad points. The bad points are what I'm trying to improve on, while passing along the good points.

Next, I look at my choices for mates. I try to make it a point to look beyond my rattery,and this is where shows come in handy. It is a big advantage to be able to look at other fanciers’ animals, many of whom will happily offer their stud’s services, or sell you a young female. I fill in the possibilities in the rest of the columns (B, C, and D) of the chart.

Once I have filled out the chart, it is much easier to evaluate which breeding would be better. I can easily see that Snazzy has good, solid, if not spectacular color. What he lacks is essentially raciness.

I have three females to choose from to breed with him. Female X represents an inbreeding to a daughter. Unfortunately, she has the same faults Snazzy does. If I breed the two of them together, I am likely to get small ears and cobby, square bodies in my line. This can be very difficult, if not impossible, to correct in the future.

Female Z is totally unrelated to Snazzy, an outcross. This female has spectacular color, wonderful dark points and shading. Snazzy’s color is good, and breeding him with this female would probably produce spectacularly colored babies.

The Breeding Chart
Rat’s Name A
Tarot’s Simply Snazzy
Female X
Female Y
Female Z
Yes Yes Yes Yes
Yes Yes Yes ?
(10 pts.)
really nice9
very long & narrow3
Eyes (5 pts.)
a little small3
good 4
very large5
Ears (5)
fairly nice4
fairly large
Type (15)
Size (5)
Tail (5)
little short4
little thin4
very thin & square1
Background (10)
my lines10
my lines,
Snazzy’s daughter
going back to
related lines
Color (10)
average for female
very dark10
Points (5)
good feet
lt. feet
very dark5
Shading (5)
good for female3
best I have ever seen5
Markings (10)
Coat (5)
TOTAL (90)

This is where you have to remember that one point does not make the rat. One feature, like color or markings, is just one piece of the puzzle. In this case, though spectacularly colored, the female’s type is terrible. Though Snazzy’s isn’t horrible, it is the major point I would want to improve on. If this breeding were done, it most likely would produce babies that had considerably better type than mom, but still much poorer that dad.

Female Y is out of lines with some of the same background as mine. She is related to Snazzy, but not closely. Her color is not spectacular, but is decent. Breeding to Snazzy would probably improve it. On the other hand, her type is better than Snazzy’s and complements his major faults. This breeding should produce babies with better color than mom, and better type than dad. An improvement on both the parents — just what all breeders strive for.

In this case it’s obvious that female Y is the one to breed to. If I had large amounts of time and space I might also breed to female Z in an attempt to bring in that spectacular color. It would probably take years to significantly improve those rats’ type, but it could be done. This, however, would have to be a side project. It would be disastrous to make this breeding the basis of continuing my line of rats.

.  .  .  one point does not make the rat .  .  .  it’s just one piece of the puzzle

For anyone that wonders, the examples I have used here are real. Snazzy was one of my very favorite boys “G.Ch. Tarot’s Simply Snazzy,” and female Y is better known as “KKS1668-2 Second Times the Charm.” Females X and Y also are real, and were considered when I decided to breed Snazzy. Snazzy was bred to Charm (female Y) and her litter produced “G.Ch. Tarot’s Simply Special.” Special represented an improvement over both his parents which he then passed along to his own offspring as well.

Though these rats have since left me (Charm just over a month or so ago at over 3 years of age), the charts I created when deciding on who to breed have been invaluable many times over. They represent a fairly complete evaluation of the qualities each of the rats in my line possess. I now have enough years’ worth to trace back and see where specific characteristics came into my line and to see track records of features that are consistently good or need improvement. That’s not how I initially planned to use these charts, but it has been a very valuable tool nonetheless. *

Tarot’s Simply Special
G.CH. Tarrot’s Simply Special

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Updated March 30, 2015