Cats are territorial creatures and usually don’t take fondly to another of their kind encroaching into their space. This can make it difficult for people who want to introduce a new kitten into a home where another cat already lives, especially if that other cat is an adult. It is likely that the adult cat will be hostile towards your new little interloper; but there are steps you can take to make sure the moving-in stage goes as smoothly as possible.
1. Isolate your new kitten. When you bring your kitten home for the first time, it will feel a little fearful. Keep the kitten in a room of its own where your other cat cannot go. This will help your kitten to become accustomed to its new surroundings without feeling threatened.
2. Carry out some cat scent swapping. Give your adult cat a piece of fabric that the kitten has been sleeping on to smell, and vice versa. This will let each cat become familiarized with the other’s scent.
3. Make the introduction. Once the kitten has settled, let the two cats see one another, but keep a physical barrier between them. For example, place the kitten in its carrier and then place this in a room with the adult cat. This way, both cats can see one another without putting the kitten in danger. The kitten may become fretful in the enclosed space of the carrier, so keep this introduction short, less than 10 minutes.
4. Remove the barriers. After a few days, start physically introducing the cats to one another, but only under supervision. Sit with your cats as they meet and ensure that there is an escape route for them both. Your cats will only become afraid and defensive if they think there is no way out of the other’s company. It will be natural for the kitten to approach the older cat, perhaps thinking it might be its mother, just as it will be natural for the older cat to hiss or spit at the youngster. This can be disconcerting for the kitten and you may want to separate them at this stage. Learn cat body language and if your adult cat shows signs of preparing for an attack on the kitten, separate them immediately.
5. Supervised meetings. Until your kitten is old enough to look after itself – around 4 or 5 months old and dependent upon its size – always supervise meetings between your cats. Until a kitten can defend itself, it is vulnerable, and an adult cat can severely injure, or even kill, a small kitten.
These steps will take time and effort on your part, but following them will help you to achieve a home life in which your adult cat and kitten, even if they do not exactly get along with each other, will at least tolerate the other’s presence.