American Fancy Rat & Mouse Association

This article is from the WSSF 2015 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Mouse Sized Baby Rats

By Karen Robbins

Steve Pellitier, Facebook
Q I need some advice. On September 11 my female rat Rosie had a litter of 4’s now October 25 and these pups are not much bigger than mice. The babies are all normal otherwise—very active, very curious, and very friendly. My female was only 8 months old when she was bred. I have been raising rats for a few years and have bred rats many times before. I have never seen anything like this. I had one mamma rat that had litters of 15 pups consistently—none of them were in any way small. Usually at 5 weeks or so, the pups are almost full grown. I’m not sure what or if there is anything I can do to help these 4 grow to a normal size. (Note: the buck that sired these little ones is huge, approximately 13" long from nose to base of his tail and 1.75 lbs. Rosie is a normal-sized female.)

They are being fed a very healthy diet, with proteins, grains, starches, fruits, and veggies. They get eggs, whole milk (fresh from the cow), tuna, rice cereal, wheat cereal, pasta, chicken breasts, veggies, etc. I have never had a rat get skinny on the diet I feed them (usually they are fat and lazy and spoiled).

Any Advice or anything I can do?

A Sometimes older females not only have smaller litters but do not produce enough milk for the babies while they are nursing so the babies are stunted. Some questions: has she had litters before and how many were in each litter if she has, do you know the backgrounds of the parents (do you know if they carry Dwarf?), do the babies seem to be eating normally—are they in good weight but just small in size?

Some thoughts are they are Dwarf, mom didn’t have enough milk while nursing to give them a good start in life which could be due to her age or some other problem, or they have something wrong with them and are not able to eat properly so are not getting enough nutrients to grow properly. We need more info on these little ones so we can perhaps help out better. Photos of them next to mom would also help.

Update: I do not know if Mamma carries a dwarf gene. It doesn’t matter to me if they are Dwarfs, they will be loved all the same. I am just concerned about their growth as compared to all the previous litters I have had. *

December 3, 2018