Q: I've recently introduced a new cat into our home but he doesn't get on at all with my other 3 cats. My house has now been divided into 'his' and 'them' territories. Should I re-home the new cat?
A: Probably the best solution for the cats would be to find a nice home for the newcomer. Cats form social groups and it's very difficult to introduce a new cat to an existing group without their being some friction. Sadly, some groups never work and it's always better for all the split them up.
There are techniques for gradual introductions but, if you have got to this stage and you don't want to give up just yet, you should consult a cat behaviour counsellor.
Q: What's the best way to introduce a new kitten to my existing cat?
A: A little bit of extra effort at the beginning can make the difference between good and a bad cat relationships in the future. Your cat is not necessarily going to welcome the new kitten with open paws! Start by placing a kitten pen* in a room that your existing cat doesn't particularly favour but allow the kitten to exercise within the room when the other cat is not around. A couple of times a day, open the door to the room whilst the kitten is eating in his pen and place a bowl of tasty food as near to the pen as you can for your existing cat to eat comfortably. Once this has happened comfortably, reduce the distance between the two cats when they are feeding by small amounts daily. It would also be useful to exchange bedding between the two to allow them to become familiar with the other's scent. After a week start to place the kitten pen in other rooms of increasing importance so that your existing cat will understand that the kitten has rights of access to all areas. Allow several weeks before opening the pen and letting the cats get to know each other. Keep a cushion or pillow handy to place between them just in case things do not go according to plan.
*A kitten pen is a large metal cage with a solid floor that is normally used for kittening queens. It is big enough for a bed, toys, food, water and a litter tray. They are often available for hire from veterinary practices or you can purchase one from any good pet shop.
Q: How do I introduce a new adult cat to my existing cat?
A: Confinement in a kitten pen can be quite distressing for an adult cat. I would recommend that the new cat is kept in a single room first rather than a cage. The existing cat should then be introduced gradually by scent, sight and touch in that order! Your cat's natural facial pheromones can be collected by stroking your cat around the head, cheeks and chin whilst wearing a pair of fine cotton gloves. Scent glands in these areas produce a pheromone that signals a positive message of security and familiarity. The gloves can then be scraped around the house at cat height against doorways and furniture. The new cat's scent can be collected and deposited in areas where the existing cat is housed and vice versa. Your cat should then be able to see the new cat before he is able to have physical contact. A wire frame to fit within the door surround can be useful for this purpose. Physical contact can then be established after a reasonable period of time and it may be useful to feed or play with both cats to distract them. It is often tempting to interfere in their initial cat interactions but, unless they risk injuring each other, it is usually best to let them sort it out in their own language.