Mouse population explosion

Question
Dear Natasha,

I have saved 10 mice from the pet shop as they were destined to be feeder mice. Two people both at the pet shop and a friend assured me they were divided by sex appropriately. Surprise surprise...now two of the 4 supposed females are pregnant. One just gave birth to 7. I am totally discouraged and don't know what to do.
1) How can I make 100% sure to re-separate them properly.?..to avoid that in the future.
2) When and how can I determine the sex of the babies?
3) I cannot take care of that many mice do you know anyone or any organization that could take them? I live in Canada but I am willing to drive anywhere to insure their safety..Please please please help.... Thank you in advance P.S.: Our SPCA dos not take any.

Answer
Hi,

Oh, dear, you've gotten yourself into a fine fix... but thank you for saving the little mice!!  Let's start with the problem of gender identification.  This excellent site will tell and show you absolutely all that you need to know:

http://www.thefunmouse.com/info/sexing.cfm

The bad news is that when the boys grow up they may fight and need numerous separate cages.  Sometimes littermates can live together and sometimes not.

Now, you tried your SPCA, but there are rat and mouse sites which may have information about adopting out extra mice.  Even though some sites or organizations mention only rats, many rat people will help with mice:

American Fancy  Rat and Mouse Association:
http://www.afrma.org/

Rat and Mouse Club of America (they have info about rescues, though unfortunately CanadaRatFinder seems to be obsolete):
http://www.rmca.org/

North American Rat and Mouse Club, Int'l:
http://narmci.8k.com/index.html

The Ratster-A Rat and Mouse Directory
http://www.ratster.com/

Follow all the links you can; it can get a little frustrating, but there are for instance also lists of veterinarians, whom you could call and ask.

Another direction to go in is to find science teachers or general classroom teachers in local schools and suggest a mouse or two as a pet.  some teachers may even want to take a pair so the kids can watch babies grow up.  You can also put up notices in the library, town hall, or anywhere that notices get put up.  You may have a local want ad paper too.  Make the notice or ad sound exciting-- write how great it is to have a mouse as a pet.  Here is a paragraph I wrote for a girl who wanted to convince her mom to let her get a mouse:

"As for convincing your mom.. Mice are the smartest small pet you can get.  They cost very little to maintain.  They are quite clean if you keep their cage clean (but they do poop and pee on you, so don't wear your best outfit holding them!).  They are very friendly, curious, tenacious, and creative, besides unbelievably cute.  They are very loving.  They don't tend to bite, like hamsters do; they are easier to hold than gerbils.  They stay in their cage so no one has to deal with them except you.  You will be learning how to care for a pet, and by extension, how to be responsible for something other than yourself; that is a very important life skill.  They only live 18-30 months, which means frequent tragedies (well, learning to deal with mortality is a skill too..) but they are not a long-term commitment.  You can leave them in their cage for up to three days (no more) as long as they have lots of food and water, including wet vegetables or fruit (carrots, apple) in case their water bottle clogs-- so you can still sleep over someone's house and Mom doesn't have to tend to the pet.  They are easy to transport to go on vacation with you or stay at someone else's house while you are gone; no in-house petsitter needed (she can't say that for the plants, now, can she?)"

You might be able to use some of that.  

I hope I have helped.  Your problem is a common one and so I made this public-- without your name on it-- so others can learn from it too.

squeaks n giggles,

Natasha