Standards are created to give the exhibition breeder a set criteria of traits to breed towards achieving and/or improving.

Standards need to be based in genetics. The reason for this is quite simple. The criteria specified needs to be genetically possible.
For example: It would be futile to set the type standard for a self black, to have say, pink eyes. In a rat or mouse showing to have the gene for pink eyes, the coat colour will also be affected, & will no longer be black.
That is just one example.

When we were developing our Standards, we wanted to make sure we had the most accurate information. First genetically and then, also within the Fancy. Initially ANRA were affiliated with Tamråttans Vänner in sweden, as we found their standard to be the one that most aspired to this. Their standards were written during the years 1995 -1997. All earlier standards mentioned in the text refer to the standards of the NFRS (the official English rat standards).

We start from "The Genetics of the Norway Rat", by Roy Robinson, concerning the year from which a specific gene is known. Information about the exact year a certain mutation or a certain variety came into existence can be hard to achieve. Therefore this data can vary in different books and articles. We base our information on both scientific data and information from within the fancy.

One problem we see in the Fancy, is that the standards have developed and changed in different ways all over the world in the many rat clubs of the world. Different names for the same genetic variety, the same name for two or more different genetic diversities. One genotype can have different phenotypes in different rat clubs.

ANRA's standard keeps up with scientific development of the knowledge about rat genetics, to provide the breeders with a complete and useful standard to use as a general outline in their breeding.

The genotype that is written beside every colour is the genotype that usually gives the best result, e.g. can be bred to the standard.

A standardized colour can be produced in different ways and it is not necessary that only one genotype is possible for a certain standard. A breeder has to decide on his/her own what genes are needed to reach the goal, e.g. a perfect rat that corresponds to the standard. While the names of colours and markings do vary with different rat clubs. Where possible, we've adopted the names given them by the geneticist that mapped the gene.

Because there are often many different names given to the same variety, to try to minimise confusion as much as possible, we have included in brackets, beside each, the name/s that other organisations give to that particular variety.

To ANRA's standards, have been added several new varieties, not as yet mapped genetically. In cases such as this, some genecodes are not known. Where even part of the code is known, that is noted.

These Standards are stipulated at the annual general meeting, held in February of each year.