Here's another:
"Myth #1: Male Guinea Pigs Can't Live Together
Somewhere, sometime, someone started a rumor that two male guinea pigs cannot live together. In time, the rumor developed into a full-blown myth that's been hard to erase. There's rarely a week that goes by that Cindy doesn't have to debunk this myth for a prospective adopter.
Fact: Two or more male guinea pigs can live together quite happily, and seem to be less prone to the kind of surprise falling-outs that we've seen within pairs and trios of females. A perfect example of a happy trio of males is Cheech, Chong and Diego, three sanctuary pigs profiled on our Web site.
Fact: Two or more males can't live together if there's a female in the cage with them. Having a girl in the mix stirs up spatting and outright fighting amongst the boys for alpha male status. Inevitably, the female, and one of the males, gets hurt. No bonded pair or trio -- no matter how long they've been together -- is immune.
Fact: In many cases, two or more males can't live together peacefully if there's a girl or two living next door in an adjoining cage. There are exceptions, but they're the minority.
Ultimately, successful matches between guinea pigs -- in any species, for that matter -- come down to individual personalities. Some mix, some don't."