Introducing New Cats to a Home with a Resident Cat(s)

Step One: Giving time to settle and adjust

Follow the procedure outlined in Settling a Cat in to their New Home (https://petcourses.co.uk/free-resources/settling-a-cat-into-their-new-home), except when they are ready to explore outside the refuge room, restrict them to a limited area just outside their refuge room, ensuring they cannot escape and that the resident cats are in a separate secure location.

Step Two: Introducing Scents

Introduce scent before face-to-face meetings as described in the Protocol for Harvesting and Transferring the Cat’s Odours to a New Environment or Object (https://petcourses.co.uk/free-resources/the-importance-of-a-cats-scent-profile).

This may naturally occur from the caregiver’s clothing but also, on separate occasions, let the resident cats explore the area outside the refuge room, where the newcomer has been.
This process can also be helped along using scent swapping.
Harvest facial odours.
Leave the cloths in areas where each cat can investigate the scent of another in their own time. Do not force them to investigate the cloths and make sure they are not placed too close to their key resources.
Whilst the cloths are in their vicinity make sure each cat is relaxed and doing something they enjoy (e.g. being given treats or being stoked) as this pairing will help to create positive associations with the new scent.
Repeat this process daily for two or three days or until the cats appear generally relaxed and settled.

During scent transference, each cat should either ignore the odour or react positively (sniffing it with a relaxed posture). If there are any signs of distress or alarm it may be that the scent was introduced too quickly or at too close a range. In those circumstances do not proceed to step three. Go back a few steps and leave the cloths some distance away so that the cat has time to process and accept the new odours.

Step Three: Eye-to-Eye Contact

Choose a time when the cats appear relaxed and recruit another person to help.
Ideally choose rooms that have a space between them – a corridor or a hallway for example. This way they won’t be able to rush towards one another and get too close too soon.
If the rooms have glass doors that’s ideal. Place each cat in the rooms on either side so they can see one another.
If these setups are not available and doors are solid, another option includes: fitting a tall baby-gate (suitable for large dogs) in open door-ways. To prevent them getting through the bars, attach garden mesh or wrap strong cling film securely in place so they can’t squeeze through the gaps but retain some visual contact.
Allow cats to gravitate to the rooms themselves rather than carrying them there.
Try to relax and let the cats explore. Let them move closer and observe their interactions.
Aggression is often indicative of stress so never use punishment. Instead use distraction with toys or food and end the session.
To avoid redirected aggression don’t lift cats up when they are behaviourally aroused.
For mild aggression take a few steps back in the introduction procedure and progress more slowly.

Step Four: Face to Face Meetings

If things progress well, limited face-to-face introductions can be made. Do not force them together or confine them in a small space.
After a session of eye-to-eye contact, open the door slightly so they can enter the room themselves.
Provide plenty of hiding places and elevated locations for cats to retreat to if they feel uncomfortable. Cat trees and clutter free shelves and book cases make good spaces.
Never force or rush the process. Gradually increase the time that the cats spend together.
To reduce any social stress, ensure that they have sufficient space and an abundant supply of key resources.
With time, cats can become great friends but some just tolerate and accept one another. Either outcome is favourable.
Remember that kittens may be exuberant and can pester an older cat. Supervise sessions and don’t allow this to happen.