American Fancy Rat & Mouse Association

This article is from the Sep./Oct. 1996 AFRMA Rat & Mouse Tales news-magazine.

Breeding & Stuff

Breeding Wild Mouse; Care For Newly Born Mice; QUESTIONS FROM CANADA: Berkshire, Tailless Baby
Breeding Wild Mouse

From our files
QI currently have a wild-caught house mouse. She was about 4 weeks old when I caught her and I’ve had her 16 months. Could she be bred with a fancy mouse in order to produce something unusual? Is she too old to breed?

AYes, your wild mouse could be bred with a fancy mouse, but at 16 months she is probably too old. Domestic mice quit breeding at about one year old. They only live one and a half to two years. The wild mice might be a little different. Most likely if you bred her to a domestic mouse, the results would be the same as breeding an Agouti fancy mouse to any other color (you would get Agouti). Breeding wild mice to fancy mice is not highly recommended, as the offspring usually have timid and skittish personalities like their wild parent. You must also be careful whenever handling wild mice or placing them in with your other mice as they can carry many parasites and diseases that would be deadly to the pet mice.

Care For Newly Born Mice

Daniel Chor-Kwo
QWe have some problems about two newly born mice. They were born 5 hours ago. Unfortunately, their parents give no attention to them. We are afraid that they would die from starvation and from the cold weather. Please suggest to us what we should do. Thanks!

AThe best thing to do would be to try and find a foster mom with babies just born and with only a few so she can feed them (a mouse can nurse 10 at a time). I have had very good luck fostering baby mice onto rat moms, if you should happen to know of someone with a rat that just had babies and you think may accept the baby mice, you may want to try that.

Baby rat

As far as bottle feeding them yourself, they will need to be fed every 2 hours. Most people use KMR (Kitten Milk Replacer) for nursing orphan rats and mice. You may also try whole, fresh goat milk; Enfamil (without iron); or Soyalac human formula. Mouse milk is composed of 12.1% fat, 9.0% protein, and 3.2% lactose. A baby bird feeding syringe with a fine curved tip or a very small doll nursing bottle will work as a nurser. You can also use a piece of absorbent string, acting like a wick from bottle to baby until they are big enough to grasp the bottle tip. They should only be fed small amounts of warm formula at each feeding, be careful not to get any milk in their lungs. You can tell when their tummies are full by the white patch in the left middle of their bellies. It may take about 5 minutes to feed each one. After feeding each baby, massage their abdomen and rectal area with a warm, damp cloth to stimulate them to urinate and pass solid wastes. This will need to be done after each feeding until they are eliminating on their own. They need to be kept warm (around 75 to 90 degrees F (24 to 32 C) in the nest). A hot water bottle wrapped in a towel in the nest or an electric heating pad (on low) on the outside bottom of the cage/carrier/box works well. I must warn you that feeding newborn rodents is not only time consuming, but the chances of their survival are not high. Karen Robbins


Colette Theriault, Canada
QI am planning a trip to Toronto sometime this summer to try and find Blue Rex or Dalmatian rats. I should have better luck since it’s a very large city (for Canada). All the other leads I had went down the drain.

I found out also that I can’t really get the rats from the States since they have to be in quarantine, there’s also duty, taxes, etc., . . . $$$$ I think you get the picture. Sometimes I do envy the people of California (except for that earthquake thing!).

My baby-sitter has what I think is a Berkshire rat. Its black with white feet and tip of tail and an irregular blotch on the belly. She decided she wanted to breed her to my fawn. I suspect all the babies will be black since that color is dominant over Fawn. She’s lucky since they are very hard to come by in Sudbury. I told her I wanted one black female from her litter.

As for Myreille, my pregnant Hooded Beige, she shouldn’t be pregnant for very much longer. She looks like she swallowed a ball. She’s so roly-poly. I can feel the babies through her abdomen. I think she’ll have about 10. When I used to breed fancy mice, I used to be able to count the babies while fondling the abdomen and I was right usually by +/- one baby. Fancy mice are much easier to get than rats. I even developed a silky albino through my breedings. You should have seen the variety!! I started with a female silky cinnamon and bred it with a dull albino male both of which had unknown backgrounds. I had lots of fun.

Do you know if I could use unscented dust-free kitty litter in the rat cages? Would it be worse than the cedar/pine shavings? I was thinking of trying it in a corner of the cage where they use for their toilet (something like a kitty litter box).

Talk to you soon. Have a nice weekend. The weather in California is most definitely warmer than here. It was only 3 degrees Celsius at 7 A.M. today. Again, it’s below average for this time of year . . . it’s time for a vacation to warmer climates. ha ha.

Tailless Baby

My rattie had her babies around 4–5 A.M. yesterday (25th). I watched/filmed most of the deliveries. When I awoke and went to check on her, she had 4 or 5 already. I witnessed twins being born and I caught it on tape.

Later that night, I decided to sex and check that the babies were okay. I almost fell off my chair as I tried to sex a tailless baby!! I couldn’t find the anus and I was worried it didn’t have any. I know that weird deformities can happen. But my worries were put to rest this morning when I noticed feces stuck in what was most definitely the anus. And it is a female. I’ll keep you posted.

AIt’s interesting that you say there is a quarantine in Canada. I shipped mice in 1994 to Victoria, Canada, and there was no quarantine.

Berkshire rats have a completely white belly, white spot on the head, white tail tip, and white feet. We have drawings on our home page. Irish rats have a round spot on the belly, white feet, and white tail tip. Of course, there are those rats in-between the two that, with work, you can make one or the other.

You may be in for a surprise when you breed your black to your friend’s Fawn rat. Fawn rats are actually Beige Agouti’s (Agouti rats which have a double dose of the ruby eyed gene). Agouti is dominant to black, so you should get Agouti babies. If the fawn is carrying black you will get some Agoutis and some blacks. If you keep two offspring from the Fawn X Black mating, and breed them together, the resulting litter should contain Agouti, Black, Fawn, and Beige babies.

I’ve heard of some people trying cat litter in their rat or mouse’s bedding, but it can be drying to the coat. I don’t know of anyone using it now in their rat cages. You can try it and see how it works and let us know.

Congratulations on your litter of rats! What luck getting a Tailless in this litter! How is she doing? I would definitely breed the parents back together to see if I could get another one. You should also keep a pair from the Tailless rat litter and breed together to try and get more. Normally, the female Tailless aren’t capable of getting bred or will die delivering the babies, although I know of a couple of people who have bred Tailless females and they had babies with no problems, so you never know. Let me know how things turn out. In our Nov./Dec. 1993 issue of AFRMA Rat and Mouse Tales we have an article on “Taillessness in the Rat” by Sara B. Conrow, dated 1915, that is quite interesting. (I found the article in some of my papers that one of our members had sent us a while back.) A copy of the newsletter is $3 plus $1 postage if you would like the complete article. There is also a short article in that issue on breeding Tailless rats. Karen Robbins *

Back to top

Updated February 13, 2015