Pregnant fancy mouse and wild girlfriend

Question
Hello Natasha,
I brought home a female fancy mouse a few days ago, to intentionally be a companion for a young wild female deer mouse I had rescued from my cat.

The deer mouse is about 5 to 7 weeks old now , and the lady at the pet store said the fancy mouse was at least 7 weeks. The angora mouse was also in a cage with a bunch of males at the pet store, due to incorrect gender identification.

After a day of being in the same cage, the fancy mouse would allow the deer mouse to clean her face and they would sleep together.

Today though, the fancy mouse is doing quite a bit of digging in one corner, picking up and moving shavings, flicking her tail, and chasing the deer mouse away from that corner and one of the little mouse huts I have set up for them.

Is the fancy mouse acting like she's pregnant and trying to make a nest? Should I separate them into different cages?

Thank you for your time,
Julia

Answer
Dear Julia,

It is never a good idea to take a doe over four weeks old who has been in a cage with bucks. This is so common. Why, oh why, can't the attendants learn basic facts about the species they handle? It's not that much to learn.

Yes, your new girl is probably pregnant. With two fancy mice I would say by all means, keep them together. Mother mice love to have a pup sitter so they can run in the wheel and eat leisurely.

I do not know how the deer mouse will act. My advice is to watch them very closely. If there is aggression on the part of the deer mouse, remove her. Or, of course, if the angora hurts the wild girl.

I wish them the best of luck and you, fun with the babies!

squeaks n giggles,

Natasha