Reptile & Amphibian Forums

I think my mouse is pregnant, but I can't believe it. I just decided to set up a breeding colony, starting with my 2 female mice. I bought a new male today, a cute little thing. I'll get a couple more females eventually. Anyway, I went to put the male in the cage and my blue female looked pregnant (her stomach is huge, and rippling ). Now I know mice are fast, but not this fast! I'm not new to breeding mice, I used to have several. But all I have (up until today) is two female mice. I've checked them and re-checked a thousand times, they're both female, no doubt. A few days ago my dog and cat (they work as a team) chased a little brown mouse through my kitchen. First wild mouse I've seen in this house. How possible is it for a wild mouse to get a "pet" mouse pregnant? The cage I have them in is fine for my girls, but if they just tried a little they might be able get out, the wire is 1/2" x 1". They just don't try. (I'm moving them to a 10 gallon bin with a 1/4" mesh top). So I assume a wild mouse could get in. I just never thought they would!

Dawn

Most likely the mouse was pregnant when you bought her. It takes 19-21 days for gestation in a mouse. If she looks like she swollowed a lightbulb, and her sides are moving or rippling as you say, she is very close to giving birth, close enough that I would suggest leaving the male out of the cage for the next 3-7 days. Butting him in now when she's so close to birthing may stress her out, causing her to eat her litter, or, he will kill th e litter as he will suspect they are not his. Better to keep him separate instead of separating the other female and the new male. Less change in teh female's environment the better.

As for the wild mouse, no, it would not have been able to breed your female, for two reasons. One, not enough time has passed..and two, they are not genetically compatable. (ie, the wild one can't knock up a domesticated mouse)

When you say "she was probably pregnant when you got her" and "not enough time has passed", you are assuming I just bought these mice. I'm no beginner here, I used to have a fair amount of mice in breeding. Of course I would think that if I just bought her she would be pregnant. I bought both, 2 definite female mice, last January or February. No other domestic mice have entered my house since, until today when I bought my little male.

I don't know how long the little wild mouse has been around, I noticed him a few days ago. He could have been around long before that.

I thought domestic mice and wild "house" mice were genetically the same. ?

Dawn

Deermice (most common wild mouse) are not genetically compatable with domesticated mice...I can't remember what stock domesticated mice originated from but everything I have heard indicated they are not compatable.

Since you had the mice for months, then there really is only a few possibilities. One is a male (I would say no right off the bat, as if you had these mice for 5 months, they would have had more than one litter by now). The next possibility is she is fat, that's it. OR, she actually has some sort of growths, or is bloated. Unless that 'wild mouse' running around was in fact a loose domestic mouse.

Pet mice were bred from the common wild house mouse, Mus Musculus (I think I spelled that right - lol). Which is what the wild mouse I saw was, so I believe it's possible. However, she seems smaller today. I'm assuming she got a bit bloated. I swear her belly was rippling, lol, but maybe I was just seeing things. Both girls are definitely, possitively girls, no doubt about it.

Thanks
Dawn

If she's much smaller now, I would check for any blood stained bedding. She could have had the babies but eaten them (or the other mice could have) if the babies were still born or she was just stressed with having the new male around. All are amoung the realm of possibilities.

Actually, how old are your female mice? If they are too old they may not produce very well or very long. If I recall correctly, you purchased these females in Febuary? So, assuming they were newly weaned, usually 4-5 weeks, they would be over 6 months old now. Mice prime breeding age, if I recall correctly, is betwteen 6-8 (or is it 5-12?) months, before the number/size and health of babies starts to decline. May be an ideal to keep a couple of the first batch's daughter's to replace the mothers as breeding stock.

She has not had any, I checked bedding and everything. She is "clean" as well. She's not alot smaller, but she is smaller.

Yeah, I was going to breed these girls once or twice and then use their daughters for breeding. Ultimately having 5 or 6 females in breeding. Both were young when I got them.

Whew, I forgot how much male mice stink! Wow, you can smell him throughout the room. I had to move the mouse cage into my bathroom so visitors wouldn't be knocked over by the smell. Cage is clean, he just stinks! It's not just that I'm not used to animal odor, I have 24 chinchillas in my living room!

Dawn

yeah, thats the only downside with breeding mice. The males have a really strong musk in their urine. Vanilla in their water bottle helps cut down the smell (hmm, one drop to a litre (quart) I think the ratio is or is it one drop to each water bottle). I have tried this in the past, didn't notice much difference overall. I wound up just keeping the mice in one room and closed it. The only way I could limit the smell drifting throughout the house.

I don't have mice anymore since my snake is old enough to eat adult mice. I bought rats because it takes alot less time to raise a baby rat to a size equivalent to an adult mouse, than raising a mouse to full adult size. (talking about 4-6 weeks from conception to fuzzy size with rats compared to 7-10 wks for mice to adult size).

Yeah, rats seem like they'd be a better choice, since I wouldn't feed the mice until they were full grown. I just love rats and I don't know it I could "disconnect" from the pet side of them. I used to breed rats as well and they were awesome, they did tricks and came when I called them. I don't know if I could kill them. But now, smelling this male mouse has me thinking about it again. I have cages, a stack of 6 (3 sets of 2), that would work well and aren't really being used. Each has an attached feeder, and a glass house in the back that could be used for raising litters (they were cages used by chinchilla ranchers, the houses in the back are actually dust baths). Plus they are very sturdy and I wouldn't have to worry about my cats breaking in. Maybe I could try it. I honestly don't remember male mice smelling this bad! lol

Dawn

A teaspoon of IMITATION Vanilla extract in a gallon of water will help with the male smell.

MissHisssss

Yes, a house mouse (Mus mus) can breed your 'lab/pet' mice. But I would suspect she isn't. If you got them in Jan/Feb they are hitting too old to breed. Adding a male either won't work, as they are old and infertile, or may work and they have problems birthing because of age or you get away with it, but they won't last long as they are heading fast to middle age and old age for breeders.
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Sonya

Haven't we warned you about tampering with the structure of a chaotic system?
Mrs. Neutron