Gay Guinea Pigs?

Question
Hello there:
Two years ago, I got 2 girl guinea pigs.  I know that sometimes, the gender is hard to determine, but I assure you, both of mine are girls.  My guinea pigs were making a lot of noise last night, and I got up to check on them; I wanted to make sure that they weren't fighting or biting each other.  Much to my suprise, the 2 pigs were having sex!  Is this common in same-sex pairs?  
Just wondering,



Joanne

Answer
Hi Joanne!

Relax, your girls are all girl.  As in many animals guinea pigs develop an order of dominance and part of that is mounting the submissive animal.  It is normal and natural and has probably been happening all along, but you've been lucky enough to miss it.  The other possibility is that the submissive animal is declaring dominance and the "pecking order" is changing.  It really isn't anything to worry about with two animals that have been living together as long as your guinea pigs have.

Hope that helps,
Annie