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Mice/Is my mouse pregnant? How can I prepare?


Hey there,

Yesterday I got a feeder mouse from my petstore,as a pet. I was told it's a male, but have had several people tell me female. I am also confident it is a female. Since both males and females were mixed together in the feeder tank, what are the chances she is pregnant? If she is, is there anything I need to do to prepare?

She still looks normal mouse size, but she seems a little chubby which I would think is odd, for so many mice living together. I've been Googling the topic, but it hasn't been super helpful.

Thanks in advane!

Hi Addylnn,

Unfortunately, the only way to tell is to wait and see if babies arrive.  The best way to prepare is to keep her food bowl and water bottle filled, and her cage clean.  You can offer tissues or ripped up toilet paper for nesting supplies, but as long as she has some kind of fluffy bedding, she'll take care of it if the time comes.  If she doesn't already have a hide  of some kind, that's a great idea, too, so she has a safe place to build her nest.

Mice have a gestation period of 21 days, give or take a couple, so if you don't see babies by about three and a half weeks past when you brought her home, she's not pregnant.  The thing about new mice is they are usually sold very young, so a little bit of fattening up is to be expected.  :)

If babies do arrive, don't disturb the cage for the first week.  After the first week, you can "spot clean" the rest of the cage as it gets dirty, by only removing bedding on the far side and replacing with clean.  Don't remove the mice to do it, just a quick switch out, and watch for babies just in case!  Momma will keep the nest clean on her own, so don't worry about that.  The babies will wean themselves in about 4-5 weeks - you'll know they are ready to separate out when they start drinking from the water bottle on their own reliably.  At that point, males should be removed from the cage.

If you have any other questions, just let me know, and congratulations on your possible litter!



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I can answer questions regarding mice as pets, mouse behavior, color and coat genetics, breeding techniques, and general health questions. I can help with caging and setup, nutrition, social issues, and what to do in most mouse emergencies (such as unplanned litters, injuries, fighting, etc.). I can also assist with questions pertaining to orphaned mouse pups, weaning litters, and questions of mating and birthing. I cannot answer questions about exotic or wild varieties of mice such as spiny or pygmy mice. *****FOR EMERGENCIES, anything requiring immediate medical intervention, PLEASE take your mouse to a professional veterinarian or wildlife rehabilitator who works with mice as soon as possible! IMPORTANT RESOURCES: Raising Orphaned Mice: Orphaned Mice Videos: Natasha's Your First Mouse: General Mouse Help: Mouse Info and Exotic Breeds:


I have enjoyed the companionship of mice nonstop since 2004, and spent a year caring for them in a lab where I learned a great deal about their breeding, social needs, and health. I spent a few years breeding them, specifically working with albinos, marked mice, angora mice, and satins. My education never stopped - I am learning something new every day from current and well-established research thanks to the wonderful folks at the Jackson Laboratory, as well as from my wonderful mousey friends online. I also love learning from my terrific questioners here on AllExperts - you folks keep my passion for these amazing animals alive and well!

East Coast Mouse Association - expired, American Fancy Rat and Mouse Association - expired

Partial University for a B.S. in Microbiology, Partial University for a 2-year degree in Veterinary Technology (RVT cert), C.E. classes in pathogens, aseptic technique, genetics, and applications

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