How to Introduce a New Cat to Your Other Pets

Cats are highly territorial. Putting a new cat in the house and leaving the animals to sort it out often leads to growling, fighting and long-lasting stress. Taking it step by step, slowly but steadily, helps your four-legged family members live together peacefully.

Preparing before the new cat arrives

Before bringing your new cat home, set up a separate room for it. It could be a spare bedroom, a study or a large bathroom, as long as the door can be closed.

• A litter box, food bowl, water bowl, bed and a hiding place such as a cardboard box.
• A scratching post and a few toys.
• Separate supplies that are not shared with your current pets in the early stage.

Take the new cat to a veterinarian before or as soon as it comes home. The vet will check for infectious diseases and parasites and advise on vaccination and deworming. This protects both the new cat and the pets you already have. Ask your veterinarian how long the health quarantine should last.

Steps to introduce the new cat to your resident cat

The process can take a few days to a few weeks, sometimes longer. Don't rush. Only move on to the next step when both cats are calm at the current one.

1. Complete separation. The new cat stays in its own room. The two cats can only hear and smell each other through the gap under the door.
2. Scent swapping. Gently rub a soft cloth on one cat's cheeks, then place it near the other cat's feeding spot. Swap blankets and toys between them. When a cat sniffs without growling, praise it and give a treat.
3. Meals on either side of the door. Place the two cats' food bowls on either side of the closed door. Start with them far from the door, then gradually move them closer.
4. Swap spaces. Let the new cat explore the house while the resident cat stays in another room for a while. Each cat gets used to the other's scent throughout the home.
5. Seeing each other. Use a pet gate or a door opened slightly and secured. Feed or play while the two cats can see each other, keeping sessions short.
6. Supervised meetings. Once both are relaxed through the barrier, let them share a room for short periods with you present. End each session while things are still going well.

Some growling and soft hissing in the early stages is normal. If either cat raises its fur, flattens its ears or tenses up, go back a step and slow down.

When your current pet is a dog

The steps are similar, but a few extra points apply.

• Your dog should know basic commands such as sit, down and stay. Keep the dog on a leash during the first meetings.
• Exercise and walk your dog before a meeting so it is calmer.
• Never let the dog chase the cat, even if you think it is only playing. The cat will be frightened and future introductions will be harder.
• Cats always need high escape routes such as shelves or cat trees that the dog cannot reach.
• Place the cat's litter box and food bowl where the dog cannot get to them.

Some dog breeds have a strong chase instinct. If your dog keeps staring, trembling or lunging even after lots of practice, ask your veterinarian or an experienced trainer for advice.

With small pets such as birds, hamsters and rabbits

Cats are predators. However gentle your cat seems, never leave it alone with birds, pet rodents, rabbits or fish. Cages and tanks must be sturdy, have lids and be kept in a room the cat cannot enter when you are out.

Keeping the peace long term

Most conflict between cats comes from competing over resources. Give each cat enough of everything so they don't have to compete.

• Have one more litter box than the number of cats, placed in different locations.
• Spread food bowls, water bowls, beds and high perches around several areas.
• Spend individual play and cuddle time with each cat, especially the resident cat.
• Keep a stable routine, without big changes to feeding and play times.

If the cats get into a real fight, don't separate them with your hands, as you can easily be bitten or scratched. Make a loud noise, put a cushion or a piece of cardboard between them, then put them in separate rooms. After that, go back to the early steps and move more slowly.

When to see a vet

Prolonged stress can affect a cat's health. Take your cat to the vet if:

• It has not eaten for more than a day, or hides constantly and won't come out.
• It urinates or defecates outside the litter box, strains to urinate or has blood in its urine.
• It overgrooms to the point of losing fur in patches.
• It has bite or scratch wounds that become swollen or ooze pus after a fight. Cat bites get infected easily even when they look small.
• The cats are still fighting fiercely after several weeks. Your veterinarian can check for underlying medical causes and advise on managing the behavior.