male guinea pig puberty/housine

Question
Hello,  

We have an 11 month old male pig and we recently adopted a 3 month old male. We moved them into a bigger cage (together) about a week after we brought the little guy home and they were getting along great until this past week (they've been housed together about a month or so now).  I've noticed the baby has developed his 'grease gland' and has been less wanting to cuddle. Yesterday the two of them got into a bad fight, teeth chattering, rumble dancing and striking each other. They did not scratch/bite to draw blood but they were showing teeth and clearly angry. We separated them and they're now in separate cages. Tonight I took them both out to eat and again the little one tried humping the big one so the big one turned around and tried to bite him. I get that the baby is going thru puberty but my question is how long should we house them separately? And if it's for a while, will be ever be able to house them together again or will they always be enemies now? Breaks my heart because for the first month or so they were getting along so well. But now the big guy seems angry all the time at the baby and the baby seems sad that the big guy doesn't want to get humped on or play all the time.
Thank you so much for your advice! Looking forward to hearing from you.

Answer
Unfortunately male guinea pigs don't usually get along unless they've been raised together. Since they've displayed that kind of serious aggression it would not be likely you will be able to keep the in the same cage.

The teeth chattering is a serious intent to do harm. These are herding animals and just like in the wild there is only one alpha male in each herd. The older male views the newcomer as a threat to his territory. Regardless of who is the younger or older, they should not be kept together.

If you are able to put a barrier in the cage they will be fine as long as there is a fence between them.  Now that the younger is becoming sexual mature he will continue to try to battle the older male, just to take over the cage as 'boss hog.'

You sometimes see people suggesting gradual introduction, but that seldom works. If they were two sows you would be able to keep them together, but the boars are like two stallions who are full of testosterone and ready to fight.

The best thing you can do is just keep them apart. When this kind of fighting occurs it ends up in one or both being seriously injured.