American Fancy Rat & Mouse Association

This article is from the Summer 2000 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Breeding Age of Rats; Weaning Mice
Breeding Age of Rats

Laurel Summerfield, Burke, VA
QI had my first litter of nine baby rats, but I was worried that mom was not taking care of them properly because she was so stressed about being totally confined after semi-freedom. Well, she settled down completely and they all survived. Half were Black Hooded and half were (I think) Lilac Hooded. We had plenty of eager children who wanted to become rat owners, but we had a shortage of willing parents, so we still have all nine. From the time the babies were born, we put the male in a cage alone, and mom in a 55-gallon tank with the babies. Four weeks after the babies were born, they somehow got together—I have no idea how, but I suppose one of the kids was responsible—and much to our surprise she had another 14 exactly 7 weeks after the first litter. They were smaller at birth than the first litter and I thought some might not make it, but they’re 4 weeks old today and all 14 are thriving. Again, we got half Black Hooded and half Lilac? Hooded. I arranged for them to go to a very high-quality, independently-owned pet store near my house next week. They’re letting me write up information about the parents and the litter to give to the buyers. When this surprise litter came about, I had no extra cages and put the first littermates together for a couple of days until I could get another cage. I had read in a generic rat book that they were not sexually mature until the age of 3 months, so I thought we were safe. Fortunately, only one of the three littermate girls got pregnant. I was really worried about her young age and her ability to take care of a litter (she was 10 weeks old when they were born), but they seem to be doing okay. There are eight in this litter and they are 6 days old now. She doesn’t seem to be as natural at it as her mother was, but she’s doing a pretty good job. Why am I so incompetent at keeping this gang under control? I’m a very experienced dog trainer who manages multiple Dalmatians with no problem, but I can’t control my rats!!

AI had to chuckle when I read this. Let’s face it, rats are designed to reproduce themselves in excess. I imagine if our female dogs came into heat every 4 days from the time they were 8 weeks old or so, we would have a much more difficult time controlling their populations. It seems like all a male rat has to do is look at a female and she gets pregnant. If it makes you feel any better, quite a few people find our club because they are in a similar situation. Unfortunately, many of the books out there don’t warn you that 6–7-week-old females can get pregnant. It also doesn’t help that kids have this habit of shall we say “confusing” the boys with the girls. I probably talk to three or four parents a month who say that those boys mysteriously got to the girls even though the kids had been warned not to take them out together. It seems kids will be kids, and it’s easy enough to have an accident happen. My last accidental litter involved a female that was inside a cage and a male who was outside of it. Nichole Royer

Weaning Mice

QMy daughter’s mouse had babies. I need to know how to wean them, and I’m having trouble finding specific information. How to wean? Remove the mother from the cage? When? How often? Do I just separate the mom when the babies can eat on their own? And what do I do with the babies if I can’t find them homes? We never planned on breeding—the mice we purchased were supposed to be girls! I had the father neutered, but do not want to keep 10 more mice. Your advice will be greatly appreciated.

AMice are weaned at 4 weeks of age. They will be eating on their own once they open their eyes but will continue to nurse until 4 weeks of age. Most people think that once the babies are eating, they don’t need mom. Wrong! They need to stay with her at least 4 weeks. With the English mice I leave them together longer before I separate the boys from the girls. Mom will stop nursing on her own. You don’t need to do anything. You can leave mom and daughters together and take out the males. Some females can get pregnant as soon as 4 weeks, so it’s important to separate them at this age. Since some males start fighting as soon as 4–6 weeks of age, you will need to house the boys in individual cages once they start to fight if you keep them. If you take the boys to the pet shop, they will most likely be sold for snake food as males have a musky odor and must live alone, so they don’t make the best of pets. Since you found a vet that neuters mice, perhaps if you could find homes for the boys, then the new owners could get them neutered and that way you can house several of the boys together. Occasionally schools take mice in as classroom pets. Karen Robbins *

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June 2, 2014