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Mice/How did my mouse get pregnant?


Hi Natasha,
It has been a while. I previously contacted you about my two mice Fern and Bleu because they had upper respiratory infections. I took them to the vet and Fern is doing lovely. Bleu however is still sneezy. This however is not why I am contacting you. About 20 days ago I came home from a lovely vacation. We were having friends take care of our fish, guinea pigs, and mice. The mice which usually reside upstairs in my room were moved on the floor of the first floor for the convenience of their new temporary care takers. Bleu has always been thinner than Fern and when I came home she looked as though she gained a little bit of weight and looked a healthy weight for the first time. I joked that she was pregnant. Not a funny joke anymore. I have noticed that Bleu has been getting bigger and bigger. Fern is 100% a female mouse so she could not have impregnated Bleu. Bleu and Fern have been very busy building a nest, that I have unfortunately disturbed a couple of times thinking it was just very cute mouse behavior. Yesterday morning as I went to take them out and play with them Bleu tried to nip me. I took her out and her sides were so much larger than usual. All of this makes me believe she is pregnant. The weight gain, the nest building, and the change in her behavior (the nip).  So now I am left believing that may have been impregnated by a wild mouse who would have had a better chance of reaching her when she was on the first floor. We have in the past had mice in our basement, though she was not down there. Is it possible she could be pregnant and that a wild mouse could be the culprit? I don't know how a mouse could have gotten in but there are bars so it might be possible they mated between the bars. Does this sound at all feasible? I'll attach a picture below. I moved them into a glass aquarium with a screen on top so that if she is pregnant the babies can't get out. I put in plenty of cozy nesting material and a new nest has already been made. I'm really quite confused as to what is happening. If you have any clue it would be great to hear from you!

Thanks so much,


I bet if you searched under How did my mouse get pregnant, you would find I have out that not only is it common, but it has happened to me!  Those little wild boys can slip through such tiny cracks:I know of no barred wire mouse cage that they can't get through. I now have a bird cage - a 4 story converted multi bird cage-which must be made to keep little tiny parakeet bills from fingers.

It is all quite cute but there is a big problem that comes along with these apparent virgin births- these half wild babies are notoriously crazy. Much worse than a plain wild mouse.

Get them into a clean cage if she hasn't already given birth, and once they are born write back. I would explain more now but I am juggling a suicidal dwarf rat. Lol!

Squeaks n giggles,  


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I can answer questions about raising mice and caring for them as pets, with knowledge from my 38 years of having fancy mice as pets. I have NO MEDICAL TRAINING and you should take a sick mouse to the vet; but if you simply can't, I will try to help you. I LOVE PHOTOS!!! I ALSO LOVE UPDATES! Let me know how the little tyke is doing later on, for better or worse, especially orphans. It also helps me to help the next person. Please first search first: use 'Natasha Mice Mouse' with whatever else your question includes. Or check out these links: **** YOUR FIRST MOUSE (my video; rough draft): **** TEN VIDEOS ON RAISING ORPHANS: **** SEXING MICE: **** And some GREAT MOUSE INFO SITES:


I have had mice for 40 years (since I was 5!). I raised them when I was a child but now I keep all females, and never fewer than three so that if one dies the others are not devastated, because they have each other.

I run Rats and Mice are Awesome on Facebook. The official name is Rats are Awesome.

B.A., M.A., M.A. in Linguistics: Yale University and University of Connecticut

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