American Fancy Rat & Mouse Association

This article is from the WSSF 2006 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Mice Won’t Reproduce; Breeding Mice

By Karen Robbins

Mice Won’t Reproduce

QI’m trying to breed my mice and I have a couple questions. I used to breed gerbils and had no problem whatsoever. I cannot get my mice to reproduce. I bought two white feeder mice from the pet shop I used to work at. The worker there picked out two full-size ones for me. They were no doubt male and female. I’ve had them a little over a month, and I haven’t seen any mating or pups. Is there anything I can do? Will they ever reproduce? Should I get a new pair?

AThere could be several reasons why your mice won’t breed. It could be the female is too old, the male is sterile, or the female is too fat to conceive. Since you got them at the pet shop, their age would be unknown. Females start breeding around 8 weeks old and are good until about 8–10 months old, sometimes a little longer. The only way to find out if the problem is the male, is to get a young female and put with him and see if she gets bred by him. You could also try this with the female you have—get a young male around 3 months old and put your female with him and see if anything happens. If the mice are fat due to genetics, there isn’t much that can be done. These fat mice must be bred young to get kids out of them and bred fairly quickly after a litter is weaned to keep them reproducing. Occasionally, it takes a while for any results to happen after you place the mice together. If after a couple months together and you still don’t have any kids, I would suggest getting new mice to work with.

Breeding Mice

QWill a brown mouse and a white mouse breed?

AYes, as long as one is a boy and one is a girl and they aren’t too old. Female mice are capable of getting pregnant as soon as 6–8 weeks of age and will stop reproducing around 8–10 months of age, sometimes a little longer. Males are fertile from about 6–8 weeks until about a year of age. Mice live 1–2 years. Any color will breed to another color, but for show purposes, it’s best to breed appropriate colors together.

To learn more on breeding mice you can read AFRMA’s Breeding Rats & Mice booklet and to learn more on mouse genetics, read AFRMA’s Mouse Genetics book; both available on our web site. *

May 30, 2015