American Fancy Rat & Mouse Association

This article is from the Summer 2002 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Breeding Rats

By Helen Pembrook

Molly Rice, St. Paul, MN
QHi. My name is Molly Rice. I decided to write a letter to you concerning fancy rats. My sister and I own two fancy rats. One male and one female. I wanted to get some information on the breeding span of these rats. I want to know how you can tell when the female is in her estrus cycle and how you can introduce the two rats. I’ve had them together a few times and my female doesn’t seem to mind the male, but when he starts to sniff her, she squeaks lightly and jumps away. She’s a really friendly rat. Most of my friends just adore her and one of them even said she’d take two babies if I ever bred them. Could you please send me as much information as possible about the breeding of fancy rats.

AYou can get the most complete rat education on breeding rats from a book. AFRMA has a breeding book, Breeding Rats & Mice: Care and Guidelines. You may also be able to find a book at your library or order one from a pet store or book store. Make sure if you are going to order and buy a book, that is has a section on breeding. Female rats can breed from 6 weeks old until they are almost 2 years old. The best time to start is when the female is about 4 months old and stop when she reaches 14 months or so. If bred too early she can become stunted, and if bred too old, she can suffer from the general stresses of pregnancy and giving birth. If you wait too long, she will go sterile and not be able to breed at all. Just remember that there is always a risk of potentially fatal complications to the female Rat in season every time she becomes pregnant. The males can be bred anytime with no ill effects on health. The female goes into estrus about every 4 days. Some show signs by wiggling of the ears and jumping around and stopping with the tail to the side “posturing,” others show no signs at all. If you put the male and female together for a week or two, they should breed. If after 3 weeks of being separated the female has not given birth, try again. Be sure to separate them before she has the babies as she can breed the same day she gives birth. Make sure the new mom has good nutrition during her pregnancy and while she is nursing. A high quality laboratory rat block is best, but normal rodent food (grain/seed mix) can be supplemented with a little dog or kitty kibble. The mom should be in a cage that does not have wire sides as the kits can get stuck or shoved out of the openings. Change to an aquarium or laboratory cage with a wire top. She will also need a water bottle and not a dish, as the babies could fall in the dish and drown. The babies can leave their mother at 5 weeks of age. You should separate the males and females at this age so you don’t get any oopsies. *

Updated February 14, 2015