There is only one thing that I could think to have happened. From wherever you got those two from, they might have just become pregnant by another male in the household or facility that they were at before coming to you, and since it was an early stage, maybe you didn't notice right away. I doubt that one of them isn't actually pregnant but just in case, take them to the local vet. One of them might appear to be pregnant, but might not be. And there is a slight possiblity that one of the female guinea pigs is actually a male, if you didn't get them checked out by a vet and only relied on the previous owner's opinion.
no
no because they are both female but they would fight if they wanted to make babies with a male.
This is partly how guinea pigs express their dominance. They are both fighting for the 'Alpha' position. This is why it is generally not a good idea to have 2 males living together.
i bought my clidren 2 'male' guinea pigs for christams a few years back , only to discover one was actually a pregnant female. They both got on wonderfully and when the litter arrived the Male was very caring towards the babies, he treated them as if they were his own.
Yes, it is possible. Watch both females for signs of pregnancy and consult with your veterinarian.
He will mate with both.
This happens often that you get a guinea pig from a pet store or neighbor that is already pregnant. Both females must have become pregnant from two different male guinea pigs or the same male. I would call that pet store or owner to complain about this, as unless you actually have no problem with buying a pregnant sow, the owner should be notified to keep his guinea pigs separate to prevent this from happening. The only good thing to come out of this is that you got more guinea pigs than you paid for.
Its best to go to a vet to find out for sure.
I have 13 guinea pigs in total, 7 girls and 6 boys.
Well if it is a male, it is possibly fighting over a female Guinea hen Or if it is both female then it should be my theory switched with the genders
No, guinea pigs need a male around in order to mate. What probably happened is your guinea pig was pregnant when you bought it. This is quite common since guinea pigs are hard to sex when they are young but can however, reproduce at a very young age.
The main difference between male and female guinea pigs is the genitalia. Both male and female guinea pigs have six nipples and fur on their abdomen. By the way, in case you didn't know, male guinea pigs are called "boars" and female guinea pigs are called "sows".