Introducing New Pets: Bonding Rabbits, Guinea Pigs, Rats and Birds

This page is for keepers adding a second animal of the same species, or re-pairing one that has lost its companion. It gives the bonding sequence for rabbits, guinea pigs, rats and birds, and the signs that mean you should separate them. Finish quarantine first. Mixing different species is covered in multi-pet households.

Bonding plan by species

Species	Best pairing	Before the first meeting	Sequence	Separate if you see
Rabbit	Neutered male plus neutered female (RSPCA)	Both neutered and healed; side-by-side enclosures with a mesh barrier (RSPCA)	Short supervised sessions in a neutral area smaller than the 9.8 × 6.6 × 3.3 ft (3 × 2 × 1 m) home, lengthened daily (RSPCA)	Boxing, growling, fur-pulling, biting, charging with ears flat, kicking, repeated head-mounting (RSPCA)
Guinea pig	Same-sex pairs, or a neutered male with females (PDSA)	A couple of days to settle, then scent-swapping bedding and toys (PDSA)	Barrier meeting, then neutral ground, then about two weeks in a neutral home (PDSA)	Teeth chattering, biting, fighting (PDSA)
Rat	Siblings, or same-sex cage-mates introduced soon after weaning at 3 weeks (RSPCA)	Neuter any males in mixed groups (RSPCA)	Young rats settle fastest; strange adult males fight (Merck)	One rat hiding, injuries, raised fur on the attacker (RSPCA)
Bird	Birds that accept each other; some never do (VCA)	30–45 days’ quarantine in a separate room (VCA)	Cages in one room far apart, moved closer gradually, then supervised contact after days to weeks (VCA)	Bullying or fighting (VCA)
Dwarf hamster	Young littermates only (RSPCA)	Groups formed early in life (RSPCA)	Don’t add members later (RSPCA)	Any fight: hamsters don’t play-fight (RSPCA)
Syrian or Chinese hamster	None. Always alone (RSPCA)	—	Never introduced	—
Mouse	Females, or males that are littermates raised without females (Merck)	—	Adult males fight, “often very savagely” (Merck)	Bite wounds on rump, tail, shoulders (Merck)

Typical timeline

There’s no fixed total duration, because pairs progress at their own pace. These are the stages and time markers the RSPCA and PDSA give:

Stage	Rabbits (RSPCA)	Guinea pigs (PDSA)
Before any contact	Heal from neutering; a buck can stay fertile for up to 6 weeks	A couple of days settling, then a couple of days scent-swapping
Barrier stage	Side-by-side until they lie calmly near each other	Enclosures together until positive signs repeat
Supervised meetings	Daily sessions in a neutral area, lengthened gradually	Neutral ground, building up to long supervised periods
Living together	Cleaned joint home, supervised at first	About the first two weeks in a set-up neither has used

Rabbit bonding, step by step

Based on the RSPCA’s bonding sequence:

1. Choose compatible rabbits of similar size, so the larger can’t injure the smaller, and with compatible temperaments.
2. Neuter both and let them heal. Males can take up to six weeks to become sterile after castration.
3. Side-by-side housing. Use secure mesh between enclosures so they can see, smell and lie next to each other without nipping. Each must be able to move away and hide.
4. Prepare a neutral area neither rabbit has lived in, or clean it thoroughly. Start it smaller than their full 9.8 × 6.6 × 3.3 ft (3 × 2 × 1 m) living space and enlarge it as they relax.
5. Short daily sessions, always supervised. Brief chasing and mounting are normal. Separate at once for persistent aggression or head-mounting, protecting your hands.
6. Lengthen the sessions until they’re consistently relaxed, then move them into a cleaned joint home, supervised at first.
7. If it stalls, go back a step to side-by-side housing. Some pairs simply aren’t compatible, and a poor introduction can make a rabbit harder to bond in future.

There’s no fixed timetable. The RSPCA says a bond “may be instant, or grow gradually”. Once bonded, keep the layout and routine stable and let them travel to the vet together. See the rabbit care guide for housing.

Guinea pigs: the PDSA sequence

1. Settle. Keep the newcomer apart for a couple of days. The stress of moving can trigger illness that it could pass on.
2. Scent-swap. Exchange bedding and toys, or swap the pigs between the two set-ups daily, for a couple of days.
3. Barrier. Put the enclosures side by side. Squeaking, sniffing, sitting by the barrier and popcorning are good signs.
4. Neutral meeting. Lots of noise, sniffing and some chasing is normal.
5. Move in. Ideally spend the first couple of weeks in a set-up neither pig has used, with no houses that have a single exit.

To split a fight, slide a clean dustpan or board between them. Don’t use your hands (PDSA). Male guinea pigs are less likely to fight if they’re neutered or introduced before weaning, and a mixed group should have only one entire male (Merck). The guinea pig page covers group sizes.

Rats, birds and hamsters

Rats. The RSPCA is clear that cage-mates should be introduced soon after weaning, and that adding or removing rats from a stable group disrupts it and can cause aggression. Strange adult males will fight (Merck). If newly introduced rats stay aggressive, especially if one is hurt, they may never reach a stable hierarchy. Separate them if the problem lasts more than a few days (RSPCA). Aggressive grooming and loud vocalising during encounters are signs of social stress (RSPCA). See the rat page.

Birds. After quarantine, VCA’s sequence is: cages in the same room some distance apart, moved gradually closer, then supervised time together after days to weeks. Some birds never accept each other, so don’t force it.

Hamsters. Never introduce Syrian or Chinese hamsters. They are solitary, and fights can cause serious injury or death (RSPCA). Even dwarf pairs can fall out later. Check them every morning, because fights happen at night. Once separated after a fight, don’t reintroduce them (RSPCA). See the hamster page.

Mistakes that end in injuries

• Putting your hand between fighting guinea pigs or rabbits. You can get bitten, and the animals can be hurt too (PDSA; RSPCA).
• Bonding in one rabbit’s home territory. Use a neutral area, or clean the space thoroughly first (RSPCA).
• Pairing an unneutered buck with a doe too soon after his operation. Males can stay fertile for up to six weeks (RSPCA).
• Reintroducing hamsters after a fight. The RSPCA advises permanent separation.
• Changing a rat’s scent before a reunion, for example with a bath. The RSPCA warns that anything altering an individual’s smell can trigger aggression.