Guinea Pig Males

Question
We bought 3 male guinea pigs from the same mother at 8 weeks old. They got on fine until about 5 months of age when two started to fight, we have had to separate them ever since. Will they ever get on again? Or do we always have to keep them separated?

Answer
Chances are you will have to keep them apart. Boars are like any other herding animal, they typically run a 'harem' or herd of their own composed of females and their young. If there's a young male in the herd they're allowed to stay until they become sexually mature and begin to try to mate with the females. At that time they're run out of the herd permanently and must find a harem of their own.

Guinea pig boars will sometimes live with other boars if there is a very young one introduced into the cage. If the older pig gets to the age of being indifferent about breeding before the young one matures they will get along fine. I've also found that two boars will live together more peacefully than three. For some reason that third boar seems to ignite the instinct to be the leader, and they start to battle over the rights to be the leader.

Boars begin to reach full sexual maturity by five or six months at which time the hormonal drive to breed empowers them to try to drive out any potential competition.

So the answer to your question is yes, you will have to separate them to keep peace in the household. Leaving them together may cause fatal injuries to the losers.