Guinea Pigs/My piggies


Hello,  I got 4 male piggies when they were young. I have had them since June. They have always been housed together and always gotten along until a couple of days ago. They were all fighting each other (including mounting) and destroying there house and everything in it. One even had a bite that bled.  I separated them into pairs and they still fought each other so I housed them independently through the night. This morning I put  them back together and they started all over again. Three of them seem to start picking on one individual and then it turns into a free for all so I took him out and left the other 3 together and they have settled down. They are all supposed to be males, but now I'm wondering if one is a female and perhaps in heat. They have always been very sweet and I want to keep them together but I don't want them to hurt each other.  As far as I can tell, their genitals all look alike.  Your feedback is greatly appreciated.  THANKS!

The behavior you describe is typical of boars (male guinea pigs) reaching their sexual maturity. Even when raised from infants male animals begin to develop their hormones and the behavior that follows. Unless they are neutered this applies to just about all of the male species.

All herding animals (horses, cattle, zebras, elephants,hippos,dogs, cats, wolves,rabbits etc) are allowed to stay in the herd while they are young. A herd is governed by the alpha male. The exception to that is elephants. They are a herd of females and the alpha female is the boss. The alpha male is the only one allowed breeding rights. This is a behavior that controls inbreeding in wild herds.

As long as the young males behave and don't challenge the alpha male everything is happy. Once they start acting on their hormones a fight begins. If the alpha male wins the youngster is banished from the herd. If the young stud wins the old alpha is sent away.

These young boys are beginning to feel the effects of their hormones. At this age the hormones are raging and the boys don't know how to deal with it. The mounting behavior is both sexual and a dominance move. The problem is there are four boys all trying for the lead role. It's not going to work.

They will continue fighting until someone gets seriously injured or even killed. Guinea pig bites will quickly develop into an abscess and the infection is a serious one. This is not something you will be able to change as they are hard wired to do what they're doing.

The exception to this is when you have a very old boar who no longer wishes to be king and will allow the young male to think he's boss. I often use my old boars as nanny boars to the young males I've weaned. But the time still comes when they must be separated. If not, the old boar will be injured by the younger one because they are persistent and won't give up.

At their age the testicles should be quite visible so I doubt you have a female in the herd. If you do she's already pregnant. But even then the fighting will continue. It's hormonally driven and it's natural instinct.

The best thing to do for all of them is to separate them. They'll be fine side by side and can touch noses through the wire, but left together is a recipe for serious injury.  

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Pat VanAllen


As is sometimes the case, people in urgent need of information have a higher degree of expectation than those of us as experts are able to give. The experts on this site do their best to give the most accurate and responsible answers possible. We ask that you remember that it is not our intention nor place to criticize the professional advice given by your veterinarian, nor is it appropriate for us to comment on the correctness of a diagnosis made by a licensed physician. Our knowledge is experience based. Although many years of breeding and showing cavies gives me a wealth of experience it cannot change the fact that we as experts are not veterinarians and therefore may occasionally have to reject questions that appear to be asking us to criticize advice given by the licensed professional. Having raised and exhibited cavies for many years I have extensive experience in cavy care and husbandry. I currently have an active breeding program for pedigreed show animals but do not encourage backyard breeding for inexperienced owners. Although I don't encourage breeding for fun I'm always happy to answer any questions from an owner who is in sincere need of help. Pet owners wanting to breed should understand that even experienced breeders have litter losses. The mortality rate is high in cavies. The chance for losing both sow and pups is always present, even with experience. Although this is a site for experts to assist owners, there is no expert in any field who has all the answers. The wisest thing a good expert can know is their limitations. Not having an answer does not diminish one's ability or knowledge. It simply shows that we recognize our limitations and operate within them.


Raised and shown cavies for many years, having aquired my first cavies in the early 1970's as pets. My caviary currently handles 65 + animals in two different breeds and several varieties. Having been in the health care industry as a licensed nurse for 35 years I have hands on experience with care and needs in both humans and cavies. Member of American Rabbit Breeders Association and American Cavy Breeders Association.

Awarded Lifetime Membership in of one of the oldest cavy clubs in the United States, on whose Board I served as Sec/Treas for six years and currently serving as President. Also editor/publisher of the club's quarterly newsletter. We are strong supporters of our youth exhibitors, most of whom are 4H members who are working on cavy projects. Through these projects they become good responsible citizens. We deal with all aspects of showing, breeding, caring for and sharing experiences in the fancy. The cavy fancy is not a new one but in some areas is still relatively unknown. Our goal is to inspire interest in high quality, responsible breeding to improve the species, not just the reproduction of guinea pigs. Our job is to educate owners to help them make the right decisions and choices in the care of their cavies.

Graduate in nursing. Certified in emergency medicine.

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