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Guinea Pigs/Guinea pigs fighting - please help!



I just brought home a new male guinea pig yesterday (about 4 months old) and introduced him to my other 2 males (both just over 1 year old) that I've had living together since they were babies. Introduction seemed to go okay and while my original pair both seem to chase and smell the new baby, they seem to get along alright with him. However, my original pair are now fighting each other (it's escalating and for the first time ever they pulled a little hair and scratched to draw just a tiny bit of blood). It seems they're fighting over who gets to own or control the new baby. One is definitely more dominant and he's the one being the attacker, but he's attacking even when the baby is not around. My original pair used to get along just fine and now I'm worried I've ruined things for good. Will their relationship go back to what it was if I return the baby? Should I try to let everything play out for a while or do I have a better chance of them getting along again if I remove the baby ASAP? I love my pigs and I'm so upset at what's been happening. I don't want the new baby to be stressed and I want my original boys to go back to being friends. Any advice on how to proceed from here???? Please help!

ANSWER: This is a situation that comes up very frequently. The difficult part is being able to solve the problem. Unfortunately we can't usually solve it the way we'd like to.

Even brothers raised from birth will come to the day when they're suddenly reaching their male maturity and peace in the cage ceases. Your two boys have been together since they were very small and have at this point been tolerant of one another.

Adding another pig whether male or female suddenly adds a new equation to the family. The older boys are acting on hormonal instinct. They view the new boy as either a potential threat or a possible breeding mate. They haven't figured out that he is not part of that, and at this point they don't care.

They have suddenly become rivals and are driven by testosterone, not loyalty. Chances are they may have lived together for awhile longer but the day would come when their natural hormonal instincts would tell them that they are rivals.

There's always a dominant pig in every heard, both male and female. In the wild all herding animals have the same drive. Young males born into the herd are viewed as family members until the days comes that one of them tries to challenge the 'king'. When that happens a fight begins and doesn't end until one of them has either been driven away or killed.

This new boar has triggered that instinct even though they've never had a female around. They've become rivals and chances are even returning the baby will not return peace to the cage. Someone will be badly injured. The boys are fighting over who will be the ruler.

This is nothing you've done wrong, it's simply nature at work. At four months of age a younmg boar is starting to reach sexual maturity and is able to impregnate a female. So he is a rival and the older boys aren't about to stand by and allow him to be part of them.     

It's uncommon for males to live together peacefully throughout their lives. If one of them is an old boar that has passed his breeding age there's no problem. The old guy will just let the youngster be the 'boss' and doesn't care. My old boars are used as nannies for the baby boys that are weaned. The old guy is no longer interested in breeding so he allows the baby to have his way.

I suspect that even returning the new boar will not change the behavior of the older boys. I would not leave them together in the hopes that they'll work it out. They won't. This is just the way nature works and we humans are not able to change it no matter how hard we try.

Separate them all to prevent them from fighting. Whether you decide to keep the other you still should expect that you'll have to have separate quarters for all of them. They'll be fine with a wired barrier between them, but need to be kept from being able to make contact.

---------- FOLLOW-UP ----------

QUESTION: Thanks. I ended up removing the baby and doing a buddy bath and reintroducing my original pair in hopes they could get along again. They have been in their cage together a day and were doing ok for a while but have started fighting a little bit again. Could it be because they heard the new young pig and know he's still nearby? I'm wondering 1. If pigs can get territorial and fight over another pig they can't see but can hear and 2. If I use a wire grid to split my cage and have 2 pigs in one of the sections and 1 pig in the other section, will the solo pig still get lonely if he can see and hear the other 2? Or does he need a cage mate as well?  And back to why I ask question 1, if I split the original pair and either divide the cage or get a new one so that I have two separate pairings, would the fact that they can see or hear eachother still cause problems?

Although it was worth a try, giving a buddy bath didn't remove the scent, it just made the hair smell good. It's unlikely you're going to be able to keep the two older pigs together. Pushing and shoving is not a big deal, but if the hair stands up and they begin swaying back and forth that's a sign that the fight is for real.

If you hear them fighting for goodness sake DON'T put you hand in the cage to break it up. You will feel the incredible pain and depth of those incisor teeth and you will pull a bloody hand out of the cage. I speak from experience. I once had a pig grab by finger so hard that when I pulled back the pig was still attached!

The safest way to break up a fight is with a leather garden glove if you have one. Just hold it by the cuff and use it to smack either or both of the pigs. Don't put it on your hand because they can and will chomp right through the leather. Again, the voice of experience.

You won't hurt either of the pigs, you will just divert their attention to make them stop, then hopefully settle down enough that you can pick up one of them and separate them. My cages have a pass through between them and I'm able to herd one of them to the other side, then lock the pass through door so they cannot reach one another. The growling will still continue for a short time, but without physical contact everyone is safe.

The rules have changed once the new pig came to town and it's not likely they will remain indifferent to one another. The best and safest thing to do is keep each one in a separate cage. They won't get lonely as they will be able to communicate through the wires, but not having actual contact will prevent the inevitable fights.

If you try to imagine a pair of stallions who have lived together since they were young, then suddenly a third horse, be it mare or stallion, enters the picture there will be no more peace. They will continue to be competitive rivals until they are apart and have their own territory.

I know we always tell people how cavies enjoy being part of a herd and having a buddy. But dogs are also pack animals but get along just fine being an 'only pet.' Your pigs will be just as happy if they're in the same room but separated enough that nobody can get their ears torn up or bitten.  

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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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