Eva's Rat Breeding Page

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This page deals only with temper issues when breeding rats - Rattus norwegicus. Also check the Eva's Rat Aggression Scale Page.

The Most Important Issue When Breeding Rats As Pets Or Show Rats - Is Temperament

When you breed any kind of animal you can just go by the book. But if you do that when breeding rats you will end up with a bunch of aggressive rats, so called "biters". There are no books around that you can buy in the pet shop or or lend in the library that tells you about how to breed rats in order to avoid the problem of biters. This problem is special for rats, I don't know any other animal that has this problem.

This is, of course, sad for the rats. But it is a problem with a solution! You have to recognize the problem first, though.

To Recognize The Problem Of Biters Among Rats

If I told you that wild rats are much less prone to bite than most pet or show rats - what do you say to that? Have you ever read the scientific litterature on rat behaviour? I did, many times. If you don't belive me - read the scientific litterature! You have to acknowledge this problem to be able to solve it!

I Understand That Biters Are Unnatural - What Do I Do To Avoid Getting Them In My Litters?

OK, here comes the problem. It is hard to eradicate biters from the rattery, since it works as an disease that:

Gets worse through generations (anticipation)
Often skips a generation (or even two...)

Therefore it is of utmost importance to learn how to know which rat has the better temperament! When you want to mate your rats, you need to know which is the best tempered male, and which is best tempered female. These are the ones you should mate, not the prettiest rats. This is because if you establish a rattery with a nice colour and type you will have a big problem trying to add good temper. But if you instead establish a rattery with good temper it is much easier to add nice colours and type later. It is the fact that bad temperament gets worse through generations that determines this. When breeding most other small pets you begin by establishing a line with good type - and add colour later, but this does not work with rats!

A very important tool is to keep accurate records, make a pedigree for every rat, write down every kind of problem, healthwise or aggressionwise on the pedigree. These records will make things easier for you!

How Do I Know Which Male Is Good Enough For Breeding?

Here are some nice rules that actually works:

Only use males older than one year - preferrably older than 13 months.
Never use a male that bites humans.
Never use a male that bites rat babies. He can turn a new baby in the cage up-side-down, but he is not allowed to bite or harm any baby rat.
Never use a male that bites rats that he already knows.

Remember that a rat male with any of these behaviours will be prone to produce rat babies woth worse behaviours that he has himself.

How Do I Know Which Female Is Good Enough For Breeding?

Here are some nice rules that actually works:

Never use a female that bites humans.
Never use a female that bites rat babies. She can turn a new baby in the cage up-side-down, but she is not allowed to bite or harm any baby rat.
Never use a female that starts a fight with or bites any rats.

Remember that a rat female with any of these behaviours will be prone to produce female rat babies with worse behaviours that she has herself, and male rat babies with much worse behaviours.

Written by Eva Johansson.