Help pregnant mouse

Question
QUESTION: Hi i had two missexed mice from the pet shop as soon as i found out a put the male in a seperate cage but i think she's pregnant with a very tiny litter because once i had a mouse who just bulged a bit snd she gave birth to 5 one was a runt poor thing he died coz his siblings kept trampling over him =( but anyway my new female mouse well it's been about a month even less then that but i think she will have them in a few days she's ripped appart her cage in the sense that every new lot of bedding a put in there she tears it off the floor the make her giant nest! but anyway she made a nest but also it seems that when she climbs for a brief second i can see bumps on her side and she kind of has a pop or pot belly plus she has pretty obvious nipples i can see every one of them! that and her sides seem to twitch quite often it's like she is breathing but no other place on her body it moving well you know twitching she is also not like herself i moved her out into a large storage container cage too steep to climb with an open lid so she gets a lot of air she's right beside me along with dad in a seperate cage she's also very frantic she's made a round paper nest in the corner and she's not acting quite herself she's very calm and slow normally she is very fast and skittish she is cleaning alot and right now she's in the nest she made last night and she's cleaning everywhere on her body so does she sound pregnant if so approxamatly when will she give birth? i was thinking some time on the weekend or next week so what should i do? i mean she is young but it was a mistake! ahe was about 4 weeks old when i got her and she's been impregnanted by the male so will her body be strong enough? her nipples almost look swollen right now so help please?

ANSWER: Hi Gaia,

Mice have a 21 day gestation period (from conception to birth), give or take a couple of days.  Take the day you separated the two, then add three weeks - this is your due date.

Her behavior sounds pretty typical, though.  Usually the momma will make the nest a day or two before she gives birth, so I would expect them pretty soon.  They usually have their litters a few hours into the night, so don't leave the light on 24-7 or she may get a little stressed out.  From this point on I wouldn't change her cage or environment and would make sure that she always has extra food and water.  She won't want to be watched, so if you happen to catch her mid-birthing, leave the light off and don't bother her until the pups are 2 or 3 days old.  I wouldn't change the cage again until the pups are at least a week old - she'll keep the nest very clean.

As far as what to do, just leave her alone, make sure she has plenty to eat and drink, and let her do her thing.  It's impossible to tell if something will go wrong with the pregnancy until something actually goes wrong, so just keep your fingers crossed and keep a close eye on her (from a distance).  Pups will start eating and drinking on their own somewhere around 3-4 weeks old - you won't need to wean them.  You will need to separate the males from the females before two months old, and they can be rehomed somewhere between 6-8 weeks of age.  The boys of the litter will not be able to be introduced to dad, but they might get along with each other if you keep the brothers together.  Males have a habit of very serious fighting, though, so if you decide to keep them, be prepared with extra cages!  The females on the other hand will want to be housed together, and even if you adopt them out it might be a good idea to keep a couple to keep momma company.  Here's a guide on sexing mice:  http://www.fancymice.info/sexing.htm

Best of luck, and congratulations on your upcoming litter!
-Tam

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

QUESTION: Hi thanks so much! i have another question i'm going to the local pet shop tomorrow and i decided to switch from newspaper to Aspen of Carefresh is Aspen safe? what is the bedding type that you have had the best luck with? and i feel kind of horrible leaving my male mouse alone i was thinking about getting someone to adopt him but he seems to be in the best position right now with me isn't it true that they will calm down and wont fight if one male is desexed? but if not i could always house him with my female after the operation becuase he's not taking being left alone too well all he is doing is sleeping on his own and not eating or drinking much i wonder if i could do something for him like maybe introduce another mouse? also when you say not to change her enironment what if everything is saturated like all of the paper is wet and smells it's not urine at least i don't think so could it be from being pregnant i was going to get new toys as well so when could the mother be in the right condition to be climbing and playing? because i thought of getting hay to put in one of those metal balls you hang on the top of the cage. so what do you sugest BTW your info has been so helpful! =)

Answer
Hi,

Yes, aspen is a very safe and inexpensive form of bedding, and is the one I use for most of my mice.  The kinds you should avoid are pine, cedar, and anything called Softwood or Softwood mix.  Carefresh is an excellent bedding and much more fun for mice to dig around in, but is much more expensive.  Either is a wonderful choice and much better than newspaper, which becomes soiled and smelly very quickly.  About the wetness - check the water bottle!  Since newspaper isn't very absorbent, a water bottle leak or dripping can cause the whole cage to become wet and smelly.  When the whole thing gets wet like that you have no choice but to change it, as it could make the her very cold and stressed.  I just meant that normally, once she makes a nest for the pups, she keeps it very clean, so unless something happens (like the whole cage is suddenly soaked) you won't want to have to disturb it for the first week.

Usually males are happiest alone or with females (which is dangerous, as females go into estrus about once every five days).  What they need for companionship can come from you - give lots of snuggles, affection, and playtime, and he should be alright.  I would not advice introducing any males to each other that were not born and raised together, as aggression can become serious very quickly, and you can wind up with a dead mouse before you realized there was real danger.  I don't know if a neutered mouse will cause fewer problems between males, because it is extremely rare to find an animal hospital that will do surgeries, especially non-health-related ones, on mice.  It requires special equipment and knowledge, and is high in risk and pain.  For most mouse owners, it is not worth the trouble or expense when compared with just housing males separately and giving them lots of attention and care.  You can still, of course, call around to your local vet offices and see if any do offer it, and how much it would cost.

As far as toys for momma, I would hold off on toys or additions to the cage (besides hides, of course) until the pups are full-grown.  Small pups who are just starting to explore can get into trouble in some toys or accessories, so just think about whatever you're interested in getting for them - if it moves or pinches, involves any high parts a baby could fall from, or could topple over easily, it probably wouldn't be safe around the pups.  I know a lot of mouse breeders who advise against wheels around small mice.  As far as the hanging hay ball, I'm not familiar with it, but if the babies can't reach it and mom can, it sounds just about perfect for her.

-Tam