Introducing a New Cat to a Resident Cat Without a Turf War

Unlike dogs, cats do not have a strong evolutionary drive to live in large social groups, and a resident cat generally regards the whole home as its territory. A new cat introduced too quickly, especially by simply letting them meet face to face, often produces a fear or aggression response that can take months to undo — far longer than a properly paced introduction would have taken in the first place.

Keep the new cat in its own room with all its own resources — food, water, litter tray, bedding — completely separate from the resident cat for at least the first several days. This gives both cats time to adjust to each other's scent under the door before any visual contact, which matters far more to cats than it might seem.

Progress through stages only once each one is calm, not on a fixed timeline — some pairs move through this in a couple of weeks, others need several months, and pushing ahead of the cats' comfort resets progress rather than speeding it up.

Hissing, growling or swatting during early stages is not unusual and does not necessarily mean the introduction has failed — but it is a signal to go back a step, not push forward. Signs of ongoing serious conflict, such as persistent hiding, spraying, weight loss or actual fighting with injury, warrant advice from a vet or qualified cat behaviourist rather than hoping it resolves on its own.