Introducing guinea pigs requires patience and a structured approach on neutral territory to give both animals the best chance of forming a peaceful bond.

Before the introduction, quarantine the new guinea pig in a separate room for two to three weeks to rule out respiratory infections, fungal conditions, or parasites that could spread to your existing pig.

Choose a neutral space that neither guinea pig has claimed as territory, such as a bathroom floor, a playpen, or a large area covered with clean towels. Spread multiple piles of hay and a few vegetable pieces around the space so both pigs have positive distractions and neither feels the need to guard a single food source.

Place both guinea pigs in the neutral area simultaneously and observe closely. Normal introductory behaviors include rumblestrutting, mounting, nose-to-nose sniffing, mild chasing, and some teeth chattering. These dominance negotiations are expected and should be allowed to play out unless they escalate.

Intervene only if you see sustained biting that draws blood, prolonged aggressive lunging with no breaks, or one pig being cornered with no escape route. Use a towel rather than bare hands to separate fighting pigs, and try again the next day.

Keep initial sessions to 20 to 30 minutes and gradually extend as the pigs grow comfortable. Once they are eating near each other and resting without tension, you can move them into a shared enclosure.

Clean the shared cage thoroughly before the move-in so neither pig's scent dominates. Provide two of everything: water bottles, food bowls, and hiding spots with two exits each so neither pig can be trapped. A minimum of 10.5 square feet for a pair is essential to reduce territorial friction.

The best pairings are typically two females, a neutered male with a female, or two males from the same litter. Avoid housing intact males and females together unless breeding is intended.