New Born Pup
Sep 2, 2020
Reaction score
Hey there! Not knowing how many guinea pigs are rehomed in the world, we regrettably went to a big box store & adopted a sow. A week later she had 2 babies! 🙄 My son at this point named both babies & the whole family fell in love w/them. The store was helpful, apologetic & gave us free food & hay for the trouble. We'll be using a rescue next time. 👍

Both babies are boys & separated from mom @ 8 wks. Shortly after we adopted another sow companion for momma. We have two cages, opposite sides of the room, they don't see or interact w/each other, I've read it can stress out boars to be close to sows. Surely they can smell/hear each other though. Boars have always been together w/out problems, until recently. They're about 1.5 years old now.

Not an expert, but I believe their cage is big enough, it's 3 feet by 4.5 feet, with 2 hideys, 2 water bottles, 2 bowls & 2 hay containers. Including a link to a video showing their behavior, if not allowed on this forum, I apologize in advance.

Guinea Pigs items 9-2-2020

Is this normal behavior? We've "separated" them until we're sure what's going on, put a divider in the middle of their cage for now. Purring & strutting has
stopped except when the doctor is movies during cage cleaning. Which is what was being done in the video. When replacing divider after cleaning the cage, the boat w/mostly white hair chews/bites the
divider's bars for a few minutes, it's the same piggy everytime that does this & it's the only time he does it.

Is it too late to have them neutered? Would that help their chances of coexisting peacefully? My sister knows more about this stuff & after she saw the video she asked "are you sure they're both male?". So now I'm like "um 🙄"....

Guinea Pigs items 9-2-2020

Thanks for feedback in advance!

My girls have same cage setup & they get along wonderfully.


Forum Donator 2021/22
Aug 2, 2018
Reaction score
Neutering will not change their behaviour at all, if they don’t get on now then neutering them won’t change that. Neutering only ends fertility in guinea pigs. I can’t open the video though so can’t see the behaviour you are referring to.
If it is just dominance of rumbling, chasing, mounting then that is fine but if it turns more aggressive or they have a fight then they need to be separated.

They can have hormone spikes which cause a change in behaviour, boars who have seemingly got on fine can suddenly decide enough is enough or it can just be a temporary increase in dominance which calms down.

Yes having boars and sows in the same room can cause problems between the boars but they can possibly be less affected if they’ve grown up around sows. It’s advised to keep with either a divider which is higher and wider than the cage or in stacked cages with the sows at the bottom.

When you remove the divider to clean do you leave the piggies in the cage Or are they removed from the cage first?

Bonds In Trouble
A Comprehensive Guide to Guinea Pig Boars
Dominance Behaviours In Guinea Pigs

For future information separating boars from sows at 8 weeks of age is far too late. Boars become fertile from 3 weeks of age and need to be separated at 3 weeks or 250g whichever comes first.
Last edited:

Eddie & Elvis

Adult Guinea Pig
Apr 8, 2020
Reaction score
I could see the videos @Piggies&buns it's on the OneDrive.
At the start the piggies are on opposite sides of the cage and the white pig runs over and starts getting right in the other ones face. The mostly white pig was doing pretty lots of rumbling while swaying his bum with his nose right in the other pigs face. He only stopped rumbling to run after the other oiggy. The other pig would stand there for a moment while the white pig rumbles and then back up a bit and run to the other side of the cage followed by the white pig. The other pig was definitely trying to get away from the white pig. At one point the white pig tried to mount the other pig.
I appreciate this description might not be good enough to be able to visualise the situation well enough but I thought I'd try.

@Shelli1016 mounting isn't just seen during mating in guinea pigs. It's also a way of asserting dominance. Male pig do it to other males and vice versa so it doesn't mean one piggy is actually female but if you are unsure it always best to double check.


Forum Donator 2020/21
Jul 31, 2017
Reaction score
It does looks a little tense. White piggy seems to be wanting to assert his dominance but the other pig doesn’t seem to want to accept it. Try separating them for a day or two and try to re-introduce them on neutral territory.

When it comes to handling etc do you always deal with the boys first?