Now I am as certain as can be that both our guinea pigs are females. I just checked again --- and have read all the websites about sexing guinea pigs.
However, their behavior is so strange! It looks like breeding behavior to me. They are following each other around, one of them is contsantly purring at the other (as if it was a male), the other one jumps and gets annoyed, etc.
Anyone have 2 females that do this to each other? Otherwise, my cavys are good friends with each other, until this odd behavior started 2 days ago.