This article is from the WSSF 2013 AFRMA Rat & Mouse Tales news-magazine.

By Karen Robbins

Sandra David, Facebook
QAnyone know why my mouse is thumping her tail against the cage accessories at my other mice?? My mice are in a 20L aquarium containing a water bowl, two large bark pieces, an upside-down flower pot, and a nest box. I sprinkle the food throughout the tank as they enjoy looking for it and it’s more natural that way, I think. I had four females and a male in there. Yesterday morning I discovered our heavily pregnant mouse had given birth, and I could only find three babies which had all been partially eaten. I took the male out, in case she had withheld any babies for a later date when she felt safer. Also, since she’s a first time mom, I thought she’d benefit from having our seasoned momma mouse to help her. Momma has three weaned adolescents right now and is nursing two more. She has been known to be territorial with her kiddos in her cage, so I put Momma’s whole nest box in the tank with the others. She and the pregnant doe are getting along just fine, but one of the other females has taken to the tail thumping since (looks like she sniffs the air too) and will chase Momma’s babies off if they get too close to her.

AA mouse that is thumping or waving its tail means it is very upset or angry with another mouse or something in its cage. Males will do this when another male is in their cage and this is a sign of aggression, as male mice shouldn’t be housed with another male (it’s rare to have a father and son or two brothers get along for long periods of time being housed together). Also, don’t try to pick up a mouse when they are doing this or you are likely to get bit.

Since you say you just recently changed the whole cage set up and social structure, your mouse is obviously very upset with having these new mice invading her home. The first thing you need to do is take the Momma mouse out with all her kids and put them back in their own cage. Any pregnant mice should also have their own cage. It is important that once you have separated a pregnant mouse, to not return it back to the community cage until the babies are all weaned. Or else make a new community cage of the mom and her daughters. Once everyone has had their kids and they are all weaned, then you can reintroduce everyone. Also, do not put a male back in with a female after she has had her kids or he will kill them. Only keep females with the male that you are planning on breeding (old females make good companions for males but be prepared that your old female may end up having kids), otherwise he should be by himself.

Mice will not hold back any babies during delivery, so it is more than likely if she had more than three, the rest were completely eaten. About the only time you might experience babies being born after the initial ones, are dead ones that got stuck inside that are delivered a couple days later. If you find a mouse has her litter, but is still lumpy and you can feel a baby or two inside, that is not good. If she doesn’t pass the dead babies a day or two later, then they will abscess inside and you could lose her. A veterinarian would need to see your mouse if this is the case.

I’ve found in group settings, killing the newborns is usually done by other females in the cage, that is why it is important to separate pregnant females into their own individual cage. While mice will usually help take take of each other’s kids and keep everyone in one pile, it sometimes does not work out that way. I’ve had several occasions where I had 2–3 pregnant females in a cage together and as each one had their babies, the babies were eaten, until the last one had her kids, then everything was fine and everyone then helped raise the last mouse’s kids. Or a pregnant female was left in a cage with other non-pregnant females only to have all the babies killed. By putting a pregnant mouse into her own cage, you not only know who her kids are, but you are able to keep tabs on them as far as growth, how the mom is with raising them, and if that is a breeding you would want to repeat.

Dawn Renee, Facebook
QHelp! I’ve always had white breeder mice. They have always been so sweet. We bought a fancy mouse and she isn’t tame at all! I dread cleaning her cage. I always get bit, then have to chase her and we are both traumatized. I don’t know what to do! I built a cardboard hotel and put it in her habitat that she stayed in while I cleaned her cage, but she still screamed a lot.

AOne thing I did when I had deer mice many years ago, was transport them in their house to a carrier while I cleaned their cage, then once the cage was clean, put their house back with them in it, so that way I didn’t stress them out by handling them or worry about them getting away (they were captive bred). This also works for other animals that you can’t handle for whatever reason. Give her treats when you go by her cage and hold treats in front of her in the cage to see if she would at least smell it. Leave the treat after a few minutes (unless she takes it from you) and after some time she should start to associate you with goodies. You can read our Trust-Training Nervous Rats to get more ideas. Also, read the post on our Facebook page on April 27, 2012, and July 30, 2012, on what one mouse owner did to get their biting mouse to stop biting.

Unfortunately, she may have not been handled much as a baby and/or is from aggressive stock (temperament is genetic), so you have your work cut out for you. You don’t say you have other mice with her. Female mice do best in colony groups (3 or more), not alone, and perhaps getting friends from the same place you got her may help.

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