wild mice

Question
QUESTION: Too late - I have ahd a wild mouse pregnant one (possibly more) of my mice
after finding 8 babies today.  My 3 females are doing a wonderful job of
mothering, I can't bear the thought of getting rid of these - what are my
options? I've heard you can neuter males - if I kept them, would they still
carry the diseases that wild mice do?  Am I crazy to try to look after them,
separating the males and females?  I estimates they are about 4-5 days old
right now

ANSWER: This is the easiest time to sex them. Hold each baby on the palm of your hand and gently lift their tail with your thumb and forefinger from your other hand so you can see their tummies. The girls will have 10 - 12 tiny nipples and the boys will just have a furry tummy. I am assuming they look all the the same so you will need to mark them in some way. One method is to mark one sex with nail polish on the middle of their back or a place that they cannot groom easily. Wait for it to completely dry before putting them back in the cage. Of course if there are any distinct markings or colors this will help you sex them later on. You will need to separate them at 4 1/2 - 5 weeks.

Just to clarify - are you saying you have had a wild male impregnate your fancy mouse or that both parents are wild mice?

If the babies are half wild they may be more difficult to tame and handle. However, you shouldn't release them into the wild as they won't be able to adapt as easily and probably won't survive. You should keep the babies if you can as their new home may decide to breed from them without knowing what they'll get! They may also be fed to snakes or given to homes with children.

If both parents are wild then you should handle them as little as possible and release them once they have weaned from their mother at least 2 miles from your home. Find a suitable spot and leave the cage with food, water and bedding in with an easy exit. That way they can return to the cage until they have fully adapted.

Castration is a procedure that only some vets will do. It can be very expensive and there a few things that can go wrong. Sometimes a blood clot will form after the operation which may result in death. I have had about 20 castrated and this has happened once. There has also been 2 cases where the testicles were too far inside the body to remove. The mice will need to be kept away from females for a few weeks until they are no longer fertile and have 'got it out of their system'.

If they are half wild you are not crazy to keep them. I had a wild boy get in with my 12 girls - I had 76 half wild mice at one point! I had to buy a much bigger cage but the hardest thing was naming them all! The babies will carry the same diseases fancy mice do so remember to wash your hands after handling them.

Please feel free to ask any more questions.

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

QUESTION: Thanks for your reply.  To clarify, yes my three femailes are fancy mice, and
the dad is a wild mouse.  He may have well impregnanted the other two, I
don;t know yet! Anyhow your reply is encouraging as I had decided I can't get
rid of these, and I wont pass them on, coz I don;t think anyone will really
want them. When you had your 72 odd half wild mice, did you find the males
fought badly together?  Was there any canabilism?  Did you bother to have the
males castrated? And was the cage you had wild mouse proof in that on other
small mice could get in and out?  I've been told to be careful that these
babies will find there way out between the bars and scatter all over the
house.  I'm contemplating having to get cages that only have bars on the
roof.  What did you do? Did the half wild mice live 2yrs approx?

Answer
Theres a good chance your other two are pregnant, I guess you'll find out soon. Thank you for doing the responisible thing and keeping the mice. It takes a true mouse lover to do that.

Unfortunately there was some fighting amongst the males and the weaker ones were eaten. I didn't see this happen but I did find the bodies which looked like they were mummified. Remember this is just natures way for species survival. If they kill the weak then the strongest will produce healthier offspring and theres more territory/food/females per male.

I didn't have these mice castrated as they all lived together. Once the weaker ones had gone there was minimal fighting. However, they were in a very big cage with plenty of hiding places. I kept the females in a tank style cage with only narrow bars on the roof to deter wild boys. It would be difficult to find a cage 100% wild mouse proof as once they get a whiff of females they will do anything to get to them. These cages were also ideal for babies as there were no bars to squeeze through.

I still have 5 half wild mice from this incident and it happened just over 2 years ago. They all have health problems though, from an eye infection to a cancerous lump. They still run miles on their wheel though!

Please feel free to ask any more questions.