How to introduce a new cat to the resident

Adding a second cat to the home is one of the most delicate processes in cat care. Getting the introduction wrong creates chronic conflicts that can last years. Getting it right, on the other hand, gives you a pair that love each other for 12-18 years.

How long does it take to accept another cat?

With the correct gradual protocol:

• Best scenario (both young sociable cats): 1-2 weeks
• Average case (one adult + a kitten or young cats): 3-6 weeks
• Difficult case (2 territorial adults): 2-4 months
• Coexistence without friendship: a possible and worthy goal if they fight

Preparation before the arrival

Before bringing in the new cat:

• An isolation room prepared with everything: litter tray, food, water, hiding spot, toys, its own scratching post
• Your home with multi-resources: 1 MORE litter tray, 1 more food bowl, 1 more water bowl, 1 more scratching post, several high spots (shelves, cat tree)
• Feliway Friends pheromones in a diffuser (start 1 week before and keep for 2 months)
• FIV/FeLV test for the new cat before cohabitation
• Warn family/visitors: no "coming to meet the new one" the first week

Phase 1: total isolation (days 1-7)

The new cat exclusively in its room. It will not see the resident this week.

• Door closed
• The resident can smell under the door (will hear and smell but not see)
• You spend time with BOTH separately
• The new one adapts to a small but comfortable space
• The resident notices someone is there but its main territory doesn't change

Signs of normal progress: the resident sniffs under the door without hissing. The new one calmly peeks at the door.

If the resident hisses intensely or vocalises: extend the phase 2-3 more days before moving on.

Phase 2: scent swapping (days 7-14)

We start to familiarise scents without visual contact:

• Take a blanket the resident slept on and put it in the new cat's room
• Take a blanket from the new cat and put it in the resident's area
• Reward with a snack or a stroke when they smell calmly
• If they hiss at the blanket, remove it and try a less-scented object (a sock worn for a few minutes)
• After 3-5 days, swap rooms: the new one goes to the living room while the resident enters the new cat's room. They steal scents without seeing each other. Repeat several times.

Goal of this phase: both smell the other without reacting negatively. When they no longer hiss at the blanket, phase 3.

Phase 3: visual meetings (days 14-21)

First visual contact but with a physical barrier:

• Day 1 of this phase: door ajar with a baby gate. Both can see and smell each other but not touch. 5-10 minutes. Reward if calm. Close the door.
• Following days: increase the duration to 30 min. Parallel play sessions (one on each side of the gate with its wand toy)
• If they hiss/growl: close the door and go back to phase 2 for a few days
• If they are calm for 3-4 days: move to phase 4

Alternative to the gate: the carrier. Put one in the carrier and leave the other loose. Same idea of barrier + sight.

Phase 4: supervised cohabitation (day 21+)

Direct contact sessions, supervised and short:

• Session 1: 5-10 min together in a neutral room (not in the resident's territory). You present the whole time. Rewards.
• Following sessions: increase the duration (15, 30, 60 min). Always supervised.
• A normal day: when everyone leaves the house, separate them again into different rooms. They are not yet left alone.
• After 2-3 calm weeks: leave them alone when you go out for short periods (15 min), increasing.

Final milestone: when they sleep in the same room without your supervision and share play or grooming, they have accepted living together.

If there's a fight, what to do

During the process, fights can happen. Handling:

1. Interrupt WITHOUT touching the cats: clap loudly, drop a book on the floor nearby, spray water into the air in general (not aimed at them)
2. NEVER pick up any cat in the middle of a fight. They will bite and scratch you out of adrenaline.
3. Separate them physically: push one away gently with a blanket/cushion
4. Shut each one in a separate room for 30-60 min to bring the adrenaline down
5. Check for injuries: deep scratches or bites require a vet (cat saliva can cause serious infections)
6. Go back 1-2 phases in the protocol. Go more slowly.

3+ fights in a week → veterinary behaviourist. They may need temporary anxiolytic medication or a more structured protocol.

Common mistakes

1. Letting them loose directly: the shock creates lasting trauma
2. Holding them so "they smell each other": increases tension
3. Rushing phases out of impatience: 2 weeks instead of 4 = chronic problems
4. Shared resources: a single litter tray, one food bowl. Creates conflict. ALWAYS multi-resources.
5. Giving more attention to the new one: the resident notices. Give MORE attention to the resident.
6. Punishing the resident for hissing: they are expressing discomfort. Telling them off = they associate the new one with scolding.
7. Shutting the resident away "so the new one can explore": a total reversal of territorial power. You go backwards.
8. Forgetting Feliway Friends pheromones: very helpful, costs £25-35

In summary: a gradual 3-4 week protocol, multi-resources, patience above all. The payoff: two cats that love each other give you mutual company, play, less boredom from separation. The emotional investment of the protocol pays off throughout their whole life.