Q: I’ve had a male guinea pig (Max) for about 7 months but he is a year and a half old. Three days ago I got another guinea pig. She is a female about 6 months old. When I first introduced them outside of a cage in an open area, they seemed as though they were going to fight. Max was trying to mate with her, but she seemed uninterested. I separated them when I thought they were about to fight. Max is twice her size, so I know he would hurt her if they got into it. I’m not sure how to make them get along. I haven’t seen them actually get into a big fight, but I was too scared to let it get to that point. Tonight, I have Max out on the floor and her cage on the floor with her in it. He keeps circling the floor purring, swaying his bum back and forth, sometimes she does it also. But then he begins chattering his teeth (she does it back sometimes). When she is in the cage, they seem like they like each other, but outside they seem to want to fight. What can I do to stop this? I am currently caging them separately due to fear of them hurting one another.
A: Female guinea pigs demonstrate disinterest toward males when not in estrous. When they are not in estrous, they look at the male as their equal more or less and as a roommate, not a mate. As they would do when introduced with a female, they want to establish who will rule the roast within the environment with the other guinea pig.
Now this guinea pig happens to be a male, but male or not one will have to be dominant. Your female sounds as if she wants to dominate, posturing by purr rumble strutting as the male is doing back to her. If one does not allow the other to mount in a nonsexual but dominating posture, then there will be fighting.
Your pair does not sound like they will be able to get along for any period of time together. You are correct in believing that the female will more than likely be hurt because she is going to fight back. She is not going to allow herself to be dominated by the male. This feeling may change one day a month when she is cycling or every 17 days for 24 hours but the behavior will return the other days of the week.
Having your guinea pigs out in a large space, with constant supervision, may be the way you will have to keep this pair. The other possibility is having the male neutered, but in most cases of neutering it will not change the demeanor of the male; it will only eliminate his ability to procreate.
If your female guinea pig does not like him now, she will more than likely not ever like him. He is simply not her type.