How to Introduce Guinea Pigs

Guinea pigs are social, herd animals. It is unnatural for them to be alone. They love companionship and social interaction with other guinea pigs. They also feel safer, and therefore happier, in groups. Guinea pigs that live in groups are more confident, mentally stimulated, eat a more varied diet and are generally healthier. Guinea pigs kept alone are typically more stressed and flightier, less active and vocal, and prone to illness. Whilst it is important you interact with your pet guinea pig, no amount of human interaction or caring can replace bonding with their own species. We advise to always have at least two guinea pigs, with safe introductions to keep them happy.

It’s really important that if you’re planning to bring a new guinea pig into your current guinea pig’s life (or into an already existing social circle) you do it slowly and carefully. This will stop any disagreements – after all, it’s not easy to live with someone you don’t know!

First and foremost, you want to make sure that you do NOT end up with a breeding pair. If you have a male, you will want another male. If you have a female, you'll want another female. This is the easiest path to take, since it doesn't require surgery to spay or neuter.

Also, their friend should always be a guinea pig (rabbits and guinea pigs don’t tend to get along well together and some rabbits will bully guinea pigs. Rabbits can also carry a bacteria which usually doesn’t affect them, but can make guinea pigs really ill).

When possible, we’d recommend getting your guinea pigs as established friends – whether they are littermates or a previously bonded pair. But if you lose one of your guinea pigs, or you already have just one guinea pig at home, you can follow these guidelines to introduce a new friend to keep them happy.

Have patience, take your time, always introduce on neutral territory, and don't give up too soon. Bonding may happen in one afternoon or it may take months.

Guinea Pig Bonding: Step-By-Step

Step 1: Seeing each other

What you don't want to do is plop the new guinea pig into your existing guinea pig's cage. Never try to introduce guinea pigs in one of their cages. Instead, give the new guinea pig a couple of days to settle in on their own- coming to a new home can be quite stressful.

Start introductions slowly- starting out with scent and sight. Ideally have two separate set ups for your guinea pigs in the early days, somewhere they can see each other, but aren’t touching (for example on opposite sides of the same room).

At the same time, start swapping their bedding, toys and other items so they get used to each other’s scent before they meet face-to-face (this is called ‘scent swapping’). You might also want to consider switching them between the two homes each day- this helps them get used to a combination of their two scents.

Step 2: Move them closer

After a couple of days of scent swapping, try moving their enclosures and runs together so they can see and smell each other through the bars. Still keep a barrier between them, but make sure they can see, smell and sit with each on either side of the barrier. At first, you’ll need to keep a close eye on them in case they start to fight- especially if they could reach their noses through the bars and give each other a nip. You may want to provide treats so they associate being close to each other with something nice!

With this step, keep an eye out for positive behaviors that means they’re getting along. Look for signs such as squeaking to each other, sniffing each other, spending time together (for example sitting on either side of the barrier) and ‘popcorning’ (sudden jumps in the air – basically your guinea pigs’ way of saying they’re happy!).

Once they keep showing positive signs, you’re ready to move on to the next stage

Step 3:Meeting face-to-face

When your guinea pigs seem happy together, they’re ready to meet properly, with no barrier between them!

Lay a blanket down in a neutral, unfamiliar territory so that neither of them see the meeting place as “theirs” and get protective over it. Make it big enough so they have room to roam and enclose it so they can't escape. Put out some toys and veggies to so they associate each other with receiving treats (make sure you provide plenty so they don’t fight over it!) Keep kids quiet and out of reach with no other distractions.

Keep a close eye on them and look for signs your guinea pigs are getting along. There will be lots of noises and interaction. Often sniffing each other, sometimes following each other or chasing, and eventually progressing to resting together and grooming. Start out with short supervised visits (10-15 minutes) and gradually build up the time as long as they stay happy together.

If you notice any signs of negative behaviors (for example biting or fighting) it’s important to separate your guinea pigs, but be very careful as you don’t want to hurt yourself or them. Don’t use your hands to get between them; have a clean dustpan or piece of board ready that you can use to slip in between the guinea pigs if they need separating. Have a couple of hand towels handy as well, which you can throw over them as a distraction if things get heated. If they do start fighting, go back a step to the scent-swapping stage for a few days before trying again.

Some guinea pigs will settle very quickly, sort out their personalities and create a firm friendship with just one meeting. Others may be more challenging and need to have a few more closely supervised sessions before they get to know each other. It’s not always love at first sight, sometimes it can take time for them to get to know each other and feel comfortable living together.

Once they’re spending long periods of time together and showing all positive behaviors, they’re ready to move in together!

Step 4: Moving in together

When your guinea pigs are happy together for long supervised periods, they will be ready to move in! Ideally, they should spend the first couple of weeks in a neutral territory neither of them have previously used, before moving them into their permanent home. However, if this isn’t possible, make sure you use a set up that both (or all) your guinea pigs have lived in recently, such as one of their houses which you’ve used for several swaps. Or, if you are adding your new guinea pig into the existing hutch where your old guinea pig lived, clean it out completely and rearrange everything so it looks like a new space.

Ensure your enclosure is big enough for two guinea pigs. An enclosure too small can increase dominant behavior and stress. It’s a good idea to have at least two water bottles and food bowls. One guinea pig may try to block the other’s access to water or food as a sign of dominance. Also provide extra tunnels and hidey holes that have multiple entries/exits. This way one guinea pig cannot corner the other.

If at any time during bonding, you’re worried your guinea pigs aren’t getting along or have concerns over their behavior, you may need to go back a few steps and give them a bit more time to bond before the big move.

Know When to Intervene

Standard safe, non-combative, dominance behavior:

These behaviors may sound serious and they should be monitored very closely, but do not separate the pigs exhibiting these behaviors. Most of the time the behaviors will continue for a while until one backs down.

Butt sniffing
Butt nudging
Chasing
Butt dragging (they are leaving their scent)
Mounting
Nose face-offs (higher in the air wins, one must lower their nose to be subservient to the other)
Teeth chattering: a little (signal of dominance)
Raised hackles (hair on the back of the neck and along the spine)
Posturing for possible attack
Teeth chattering: sustained (signal of anger, aggression, warning)
Nips, light bites (may result in little tufts of fur in their teeth)
Wide yawn (they are showing their teeth)
Snorting (like a strong puff or hiss)

Fighting with intent to harm:

If the posturing of the nipping and bite attacks gets more serious, it's time to separate the guinea pigs. If blood is drawn, it's definitely time to stop the session. Look for these behaviors as an indicator of when to separate them.

Bite attacks are no longer warning nips, they are lunges with intent to harm.
Combination of raised hackles, loud and angry teeth chattering, rumblestrutting in place with the head staying in one position while facing the other guinea pig doing the same thing. Usually a signal of a biting attack. But they may back down before they engage.
Both pigs rear up on their haunches, face to face. This is a clear, brief signal of their intent to launch full attacks at each other. Separate if possible before the attack.
Full battle. The pigs are locked together in a vicious ball of fur. This is very serious. Separate immediately, but be careful. Throw a towel over them and use a dustpan or something other than your hand to separate them. Unintended bites from their very sharp incisors can cause serious damage.

If all else fails – give them a bath!

Here is another technique used for harder-to-introduce couples or trios, especially when adding a new male to a bonded male pair. You will only want to try this method if you are already competent at handling guinea pigs and giving baths.

When you are ready to "introduce" the three, take everybody out and put them on the floor. Lay a blanket down and enclose it so they can't escape. Make it big enough so they have room to roam around. They will all notice each other.
Watch their behavior closely. You will notice some things right away. If they dislike each other, it will be apparent pretty quickly. There will be teeth chattering along with more serious fighting. They may leap at each other and start fighting, in which case you should have an oven mitt, dust pan or towel you can wrap around your hand to separate them. Do not use bare hands. Fighting pigs will bite anything, and may draw blood. Make sure no small children are around.
If nobody fights right away, you can relax a bit. They may rumble around and mount each other. This is all normal. You will notice a lot of bum-sniffing and chasing, also fine. If the guinea pigs start fighting, refer to the above.
The ideal outcome is instant acceptance. They will run up to each other, sniff, maybe mount a few times, and then settle down to groom the other pig. This is fantastic, but unfortunately doesn't happen all that often right from the start.
If the pigs fight, or fight after a little while, give them all a bath. You can put all three pigs in the bathtub (keep the oven mitt handy) and run about 1 inch of warm water. Soap them all up at the same time with something that smells good. Use a small-animal shampoo that is kitten or bunny-safe (not a baby or human shampoo). The pigs will be distracted by the bath and forget that they are mad at each other. Don't get any water in the eyes, nose, or ears. Rinse them off carefully and well making sure that you get all the soap out.
Put them on some towels on the bathroom floor and dry them off as much as possible with a towel. Finish drying them with a hairdryer. Make sure it's on the WARM setting, and never get it too close to their skin. Make sure your hand is always on their fur so you can feel the level of heat you are giving them. They may try to run away, but continue drying them until all three pigs are completely dry. When you're done, they will all smell exactly the same.
Try the introductions again, this time on a new blanket that's just out of the dryer or is completely clean. They shouldn't fight. The bathroom scare will hopefully cause them to bond together, and they will group together out of necessity.
If the introductions go well, clean the two boars' cage very thoroughly. Use a vinegar and water solution to clean the Coroplast and throw all other items (pigloo, food dish, etc.) in the dishwasher. Clean any other hidey boxes or toys. You want to remove ALL scents from the cage. When you replace all the items, move them around so that nothing is in the same place as it used to be.
Then put all three boars in the new cage. They will feel that it's an entirely new home and won't be so territorial about defending it against the new boar.

Good luck with introducing your piggies, and remember to be patient!

Sources:

https://www.somerzby.com.au/blog/how-to-introduce-guinea-pigs-to-each-other/

https://www.pdsa.org.uk/pet-help-and-advice/looking-after-your-pet/small-pets/introducing-guinea-pigs

https://www.animalhumanesociety.org/behavior/guinea-pig-bonding-basics