Best Practices Include:
• Don't let unvetted pets interact. If you're adopting a new kitten or stray who still needs to be tested for diseases, and get vaccines, flea & tick meds, and spay or neuter, keep them separated until they're all clear. That way if they're ill, your existing pets are more protected.
• Do introduce new cat to your other cat slowly and carefully. As soon as you bring home your new cat, keep the new cat isolated from your other cat in a small room behind a closed door at all times. Let your other pet sniff and paw at the door. There may be hissing and growling, but don't worry. If you follow these tips, they could become friends — or at least peacefully tolerate each other.
Use the "smell before see, see before touch" method. Right away, swap items like blankets and beds between your new cat and your existing cat, so they can get used to each other's scent.
Hopefully your existing cat already enjoys scheduled mealtimes. It's important they do. After a couple days of scent swapping and getting used to each other, once anxiety turns to curiosity, begin slowly moving each cats' food bowls closer to the closed door. Yes, keep the door closed. This is why feeding everyone together only at scheduled mealtimes is so important. Be sure to stand nearby, observe, adjust, and be ready to intervene if needed. The goal is for the cats to ignore each other and just eat. With each meal, move the bowls a little closer to the door until they're directly on opposite sides.
Once your fuzzy buddies peacefully share a few meals directly on opposite sides of the door, try implementing the "see before touch" part of the method. This is when you begin feeding meals while the door is open but blocked by very sturdy, tall, see-through barricade such as a baby gate that the pets can't jump, but where they can see each other. Again, be sure you're supervising. The goal is for them to ignore each other and just eat. If there's hissing or growling instead of eating, close the door and let them eat alone with bowls still close to the door, then try again at the next mealtime. It will likely take a few tries before they accept each other. If they successfully eat together, then after the meal, close the door and go back to isolating.
After a day or two of happy baby gate meals, try removing the gate and supervising feedings with the door open and unblocked. Remember, the goal is still for the cats to ignore each other and just eat. See if and how they interact after the meal. If they smell, gently touch and interact peacefully, you're well on your way to a happy home. If there's hissing, growling or swatting, revert back to baby gate feedings and try again in a day or two.
You may need to repeat some of these steps a few times until everyone accepts each other. Once all pets successfully share a few meals together while they can see each other, you can try letting them physically touch and interact. Be sure to supervise and reinstate isolation if needed.
• Don't forget to show your other pets plenty of extra love. Sure, there will be much to do for your new cat, but don't forget about your other pets. They'll likely feel jealous and/or territorial. Keep their routine as much as possible, praise their good behavior (treats, anyone?) play with them, and show them extra love and affection.
Mara Robinson is a professional pet photographer in Akron, Ohio who loves creating beautiful animal portraits for her clients. She's also a longtime pet parent who knows the importance of having beautiful photos to help keep our fuzzy buddies safe; help them be returned if they escape; celebrate their growth and personalities; and remember them fondly decades from now.