How to Introduce Two Guinea Pigs to Each Other

How to Introduce Two Guinea Pigs to Each Other

Three Parts:Understanding the Role of GenderIntroducing the Guinea PigsKnowing when to Intervene

Guinea pigs are social animals. In their natural habitat in the wild, guinea pigs exist in herds. Most domestic guinea pigs prefer to be around other animals and adopting another guinea pig can have a positive change on your pet’s life. However, guinea pigs are territorial and any major change should be made gradually to assure things go smoothly. Take proper precautions and follow specific protocol when introducing a guinea pig to a new companion.[1]

EditPart 1 of 3: Understanding the Role of Gender

  1. 1
    Determine the gender of your guinea pigs. Gender makes a big deal when it comes to how guinea pigs interact with one another. Before you introduce them, you must determine their gender. Pet shop employees often make mistakes, and if you’re buying a guinea pig from a department store the chance of error is even higher.[2]

    • You should examine your guinea pig on the floor or a very low table. This way, if they get away they will not injure themselves falling. Handle your guinea pig gently, but keep a firm hold around their chest and shoulders. Spread their back legs apart to examine their genitals.[3]
    • The distance between the genitals and anus is greater in males than females.[4]
    • The genital opening of male guinea pigs is shaped like a circular dot, while the genital opening of females forms a Y-shape.[5]
    • The genital region of male guinea pigs appears to bulge outward slightly, while it appears flat in females.[6]
  2. 2
    Know what gender combinations work best. Certain gender pairs work better than others when it comes to guinea pigs.

    • Two baby guinea pigs of the same sex get along the easiest. They start off on a more or less blank slate and then grow and change together.[7]
    • If you already have an older guinea pig, getting a baby of the same gender is a good choice. The adult will not feel as threatened by a baby and its dominance will not be challenged.[8]
    • Its best to neuter males before introducing them to females. However, neutered or not, do not place more than one male in a group with females. They will fight over the female’s attention.[9]
    • Adult females tend to get along more readily than adult males.[10]
  3. 3
    Make special accommodations if you have two adult males. Male guinea pigs are very territorial, and if you’re introducing two adult males take certain precautions.

    • While two males can potentially live together happily, males may do better living in groups of 3 or more.[11]
    • A spacious cage is key to males living in harmony. Provide them with their own space to eat, hide, sleep, and eat.[12]
    • Be very careful of introducing females if you have two males living together already. One of the main reasons males fight is over a female’s attention. If you already have two males, aim to get a third male rather than introducing a female.[13]

EditPart 2 of 3: Introducing the Guinea Pigs

  1. 1
    Quarantine the new guinea pig. You should keep your guinea pigs separate from one another for the first two to three weeks. Do not let them have physical contact until this time period is up.

    • Placing the new guinea directly in the cage with a new pig can cause undue stress as he or she must be eased into a new environment.
    • In addition to the emotional concerns, many guinea pig illnesses, which are easily spread at pet and department stores, can incubate for long periods. You need to make sure your new guinea shows no signs of sickness before introducing him to your old guinea.[14]
    • Put the guinea pigs in separate cages next to each other. Position the cages in such a way that the guinea pigs cannot see each other but can smell and hear one another.[15]
  2. Introduce Two Guinea Pigs to Each Other Step 1.jpg
    Introduce them on a neutral ground. Once the two to three week quarantine period has passed, it’s time to introduce the guinea pigs. However, do not place the new guinea pig in the cage right away as it’s best to introduce them on neutral ground so neither guinea pig feels their territory is being threatened.

    • Find a new territory where neither guinea pig has been before, but that is a secluded and quiet place where both guinea pigs will feel safe. On the floor of a closed off and small room, such as a bathroom, is a good option.[16]
    • Put veggies, treats, and hay in the center of the area to distract the guinea pigs from fighting as they get accustom to one another’s presence.[17]
    • In case the guinea pigs get physically aggressive, you should have old towels on hand. You can use towels to restrain the guinea pigs while avoiding getting scratched yourself.[18]
  3. Introduce Two Guinea Pigs to Each Other Step 2.jpg
    Take precautions before putting the guinea pigs in a cage together. After the guinea pigs have been introduced, there steps you can take to smoothen the transition before placing them in the same cage.

    • Make adjustments to the cage. Guinea pigs are territorial, so make sure your cage has enough space. As a general rule, a cage between 7.5 and 10.5 square feet is recommended for two guinea pigs. More room is preferred, and if you’re housing three or more guinea pigs aim for at least 13 square feet.[19]
    • Lavender oil and shampoo can help ease the transition, as it masks guinea pigs natural scent and makes them less hostile towards one another. You can bathe the guinea pigs in lavender shampoo or dab lavender oil on the guinea pigs’ noses.[20]
    • Rearrange and wash the cage so it will smell new and feel more like neutral territory for both guinea pigs.[21]
    • Gently rub hay from the old cage on the new guinea pig so he smells morel like the rest of the herd.[22]

EditPart 3 of 3: Knowing when to Intervene

  1. 1
    Understand guinea pig body language. The first few weeks for guinea pig cohabitation can be rough, and you should expect some fighting between your pets. Know how guinea pigs communicate, and watch for any signs of aggression.

    • Bottom sniffing and nudging is a guinea pig’s way of greeting a new companion. This is normal and non-threatening behavior. Your guinea pigs may also want to establish their territory by dragging their bottoms across the ground or raising their heads up on occasion to expression dominance, behaviors that are normal during the first few weeks.[23]
    • Guinea pigs sometimes engage in a behavior called rumblestrutting. This is when they walk past each other waving their hips from side to side with their fur puffed out while making a rumbling sound. This is an expression of dominance and unless it’s followed up by aggressive gestures it’s usually a normal component of establishing the pecking order.[24]
    • Mounting or jumping over one another can lead to aggression if one guinea pig resists or retaliates. Keep an eye on this behavior, but do not intervene unless it leads to fighting.[25]
    • Squealing, chasing, and teeth chattering are common in the first few weeks. Guinea pigs may also gently nip one another if annoyed, and such behaviors are necessary to establishing boundaries between the guinea pigs. Only intervene if the guinea pigs are biting hard enough to inflict wounds.[26]
    • If one guinea pig is constantly chattering his teeth, this is a sign of aggression that could grow serious. Intervene by separating the guinea pigs if you notice this occurring.[27]
    • Raised hair, especially around the neck, and feet stamping are signs guinea pigs are preparing to fight. Separate them if you notice this behavior.[28]
    • Running at each other means they’ve gone into fight mode and you need to intervene as such scraps can lead to bloodshed and serious injury.[29]
  2. 2
    Break up fights when necessary. If fights start to get bloody, you need to intervene. Know how to do so safely to diminish harm for yourself and your pets.

    • Act quickly. Guinea pigs have sharp teeth and are capable of inflicting serious harm on one another. If you notice aggressive fighting, separate them immediately. Guinea pigs can cause permanent injury and disabilities to one another if left unchecked.[30]
    • Do not intervene with your bare hands. An irate guinea pig can cause injuries to you that are serious enough to warrant medical attention. Cover the animal with an old towel or rag or use heavy gloves while separating them.[31]
    • Separate the guinea pigs after the fight. Keep them in different cages in different rooms so they cannot see or hear each other. Continue handling them with gloves or a towel for a few hours after the fight, as they can remain skittish and aggressive for awhile after a confrontation.[32]
    • Reintroduce them slowly, once again introducing them on a neutral ground with treats and food as distractions. Depending on the severity of the fight, wait a few hours to a few days. Keep protective gear on hand in case the fight resumes.[33]
  3. 3
    Don’t be discouraged if they don’t get along. Some guinea pigs may simply not get along, even after you follow the proper protocol introducing them. You need to be prepared for this. It’s a risk when introducing a new guinea pig to your pack.

    • Do not feel as if this is your fault. Nature simply works this way, and guinea pigs have different personalities. Some may be more independent and aggressive and therefore harder to introduce to a companion. Even when you do all the right things, guinea pigs are sometimes simply not compatible with one another.[34]
    • If the first introduction leads to an excess of fighting, you can restart the introduction process, beginning again with the quarantine period. This gives the guinea pigs time to cool off and forget any previous hostilities.
    • If guinea pigs are simply not getting along, you can always keep them in separate cages where they can smell, see, and hear one another but cannot physically interact. They get the benefits of some social interaction but without the stress of a hostile environment.[35]


  • Neuter male guinea pigs, as this tends to make them less territorial. The spaying process for females is a more complicated medical procedure, so it’s easier to neuter the male.
  • Socialization is a lot easier when one guinea pig is younger. Consider adopting a baby of the same gender as your current guinea pig.
  • If possible, adopt two guinea pigs who were raised together. This way, you know they are already compatible.


  • Guinea pigs are small, but strong. When they are under duress, use precaution when handling them to avoid injury.
  • Guinea pigs can become quite aggressive with one another and can inflict permanent injury on their cage mates when fighting. If you notice a fight getting aggressive, intervene immediately.
  • Never introduce an un-castrated male to females. Guinea pigs reproduce very quickly.

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