pregnate guinea pigs

Question
I recently just got 2 pigs. There both girls while at least i thought so. I'm very
confused my guinea pigs were humping each other i thought they were just
playing so i let them be. Soon after one of the females"kisses" started rapidly
gaining weight and not being very active or friendly when i tried to take her
out of her cage i decided to sex the other girl and i found out she might be a  
he i have separated them just in case but now my other pig"midnight" has
been going through the same signs  kisses has been going through im so
confused please help me!

Answer
Hi Sami Jo,

Firstly, I suggest you search the internet for "sexing guinea pigs". Once you know what you're looking for, you should be able to tell the difference easily - on piggies as young as two weeks old.

It would be unusual for two females to hump each other, and with the weight gain and decline in activity I suspect Kisses is probably pregnant. Is she eating and drinking more, and is the weight focused on either side of her belly (so she looks like an eggplant or aubergine from above)?

Midnight - presuming she is in fact a he, and not that Kisses was pregnant when you bought her - is probably feeling lonely. Guinea pigs are very social and whilst you were right to separate them if they are of opposite sexes, it would be better for them if they can live in a divided hutch (so they can see and talk, but not touch) or each have a same-sex cagemate (though babies may solve this problem).

I hope this helps and if you have any other questions, just ask!

Jenny.