how long does a mouse live?

Question
QUESTION: 12 days ago 2 deer mice babies fell out of insulation I had unwrapped from around flower pots on our deck. I tucked them back into their "nest" and placed it nearby the flower pot, but after watching for over 5 hours, the mother was obviously not coming back. Based on various photos on the web, I figured they were 4-5 days old at the time. Fearing they would quickly starve and succumb to the cold here in Boulder, CO., I brought them in and made a home in a 10 gal. fish tank, with a heating pad in it and dropper fed them for 10 days/nights with kitten formula mixed with a tiny bit of baby cereal. One baby always seemed smaller than the other, and her "underdevelopment" became more obvious as the days progressed and the bigger one became much bigger. Two days ago the larger of the 2 opened it's eyes, confirming that they were indeed about 4 days old when I found them. That day I noticed the smaller one did not seem to eat well from the dropper, and she died in my hand that afternoon. She mildly convulsed, and it took about an hour for her to finally pass. I rubbed her gently, but knew there was nothing I could do.

Her surviving sister seems much healthier and bigger. I still dropper feed her and she's starting to lick baby cereal off my finger. I'm hoping she'll start eating more solid foods soon. I realize she just recently opened her eyes and that solid foods will come gradually? I've put tiny bits of apple, cracker and carrots in her aquarium, but so far she doesn't eat from that selection. She doesn't seem as active as many of the two week olds you describe in some of your answers. I plan on buying her a wheel, but can't picture her using it! She's very docile and likes to be held.

My main concern is, I'm wondering if she'll be lonely all by herself? If she survives and thrives, I plan on trying to find her a home with someone ( I have ferrets, and don't want to keep mousy and risk death at their hands (paws!)!). Would it be wise to buy her a companion female fancy mouse, or would they not get along being different breeds? Thank you so much!

ANSWER: Dear Maria,

I used to think that a wild mouse would be too aggressive for a tame mouse. But now I have met several people who have had success with such a pairing, and no one has happened to tell me they tried and failed (of course, in such a situation it would be too late to write to me anyway, so that doesn't mean it doesn't happen). In any case, it seems to make sense to try.

You should probably get the tiniest baby you can find (ask a pet store when they will have just weaned babies, usually at 3 weeks old). That way, neither one should be in aggressive mode. If you have to wait a few weeks, though, then it is better to get a very full-grown mouse who would then be loathe to attack just a baby. But first make VERY SURE your mouse (and the other) is a girl!! I have also heard of mixed-species breeding!

http://www.thefunmouse.com/info/sexing.cfm

Please let me know how it goes. I am still learning about this topic. You can post a follow-up question to this one. I will truly appreciate it. I wish I could get more people to let me know what happens, so I can find out if my advice doesn't work.

As for the weaning, 3 weeks is a pretty bare minimum. I would give the mouse the formula until she refuses it, or until 4 weeks. Yes it is good to just leave bits of food in the cage. Soy yogurt is a great intermediate food; then soft cheeses. Give her a water bottle now, and at three weeks, or when she refuses the formula before three weeks, show it to her perhaps twice a day (bring her to it and show her there is water on it, as best you can). Until she learns the water bottle of course she will need a shallow, tiny dish of water (that she can't fall into).

And as for the sister, mice do convulse as they die, so that was normal. She may have been unhealthy from the start, or a runt, And also it is very hard to be a mouse mommy, and she had had a terrible shock. You obviously did your best!

squeaks n giggles,

Natasha

---------- FOLLOW-UP ----------

QUESTION: Thanks so much for your prompt answer - you obviously care so much about these tiny little creatures! I think I will wait a few weeks before buying a companion, and will ask a Vet friend if she can help me make sure of the sex of this baby! I'm basing my "guess" that she's female on the fact that I may have seen nipples on her and her sister before they got furry, and that their urethras seemed close to the anus like the photos shown of the does vs. the bucks online. But as everyone points out, it's VERY difficult to be sure!

3 more questions for you: I am definitely still nursing her- about every 4 hours, except have cut back to a midnight and then 5 am feeding. Do the chances of aspiration decrease as they get older? It seems like it would since she seems more in control of how much she eats now.

I was wondering what you mean when you say "soft" cheese. Do you mean something like Brie? Per your suggestion, I'll buy some soy yogurt tomorrow.

I noticed you say wild mice tend to live longer than fancy mice. Do you mean about 3 years total lifespan?

I certainly will let you know what happens!

Marla

Answer
Dear Maria,

If she has nipples she is a girl; boy mice don't have nipples (though boy rats do; go figure?!).

I think you are right that she is more in control of her eating at a more advanced age; also, you and she have both gotten into a habit that she knows. You just have to make sure you are not forcing the liquid into her so that it would come out of her nose.

Soft cheese might be something like a mild brie; or slightly less soft, even a mild swiss, monterey jack, or muenster. I'd go for as mild as possible, not that I have ever asked a baby mouse.

I have never had a wild mouse, and you always find people saying their mouse or rat lived an outrageously long time. However, I would say three years is probably a good guess. Well bred pet store mice and fancy mice normally live anywhere from 15 to 30 months; with the extremes being rare. I can imagine a wild mouse would live, at the very least, two years; about three might be a good guesstimate.

I hope she has a long, happy life!

<:3  )--~

Natasha

PS just got a letter about a wild mouse found at 2 days who is still going at 3 years.