Guinea pig breeding habits

Question
I recently discovered my new Guinea pig is pregnant.  We have had her since before Thanksgiving and owned one Guinea pig before we got her.  We were told the one we had already was a girl and so wanted another female.  We never saw ours mount the new one at any time.  Do you think she was pregnant when we got her?  She was much smaller and so I believe she was young when we got her but now I don't know what to do!!  Should I separate these just in case we have a male and a female? Should I make some kind of home for the babies?  Please help!!
Sincerely ,  Nancy Frey

Answer
Nancy -

First, let me apologise for the delay in my response.  I have been seriously ill for about a week, and I was unable to respond to any of my emails.  Now I am trying to catch up with my allexperts posting.  Hopefully I will get caught up today.  :)  I just don't want you to think I was trying to ignore you.

Second, if you bought your animals at a pet store, please be aware that they are notorious for mis-sexing animals.  You can attempt to do it yourself, or, for a more positive ID (if you are nervous about trying to do it yourself), you can ask your vet or any reputable breeder to do it for you.  You can find directions for do-it-yourself sexing at www.guinealynx.info.  Just click on the "sexing" link.

Since pet stores are often unable to sex correctly, there is also a possibility that she was pregnant when you bought her, depending on whether you discover your previous animal is actually male or female.  However, since she is already pregnant, I don't see any reason why you should separate the two of them for now.  Keep in mind though, that you will probably want to separate the in-pig sow out jsut before birth.  This will prevent the other animal from accidentally trampling the babies.

You will not need to make any sort of preparations for the babies, except to provide your in-pig sow with plenty of vitamin c and handle her as little as possible.  If you want, you can provide a small, brown cardboard box with a hole cut into it for her and the babies to hide in, but keep in mind that if you do, you may not be able to witness the birth.  (Although you may not be able to witness it anyway, since guinea pigs usually manage to have their babies overnight or while you are not home.)

Hope this is helpful.  If you have any more questions, please feel free to contact me again - hopefully I will be able to respond much more quickly now that I am better.  Thanks, and good luck with your animals.

Lorena