Very odd guinea pig behavior!!

Question
I have 2 guinea pigs.  I have had one for about 8-9 months and i just got another guinea pig that is probably about the same age about 3-4 months ago.  Within the last month the guinea pig ive had longer is doing what ive looked up as a mating dance when she purrs and struts her butt on front of my other pig. However i have been guaranteed they are both females. Now today i have noticed that she is now chasing her and mounting her after doing her dance. Is this something i need to be concerned about or is this some kind of senority kind of thing?  HELP!!

Answer
Hi Molly

Its more unusual in females, but it does sound like your pigs are belatedly deciding which of them is the boss pig. You only really need to be concerned if they start fighting. The behaviour you are experiencing should die down within a few weeks.

andy