EVEN though they are solitary by nature, most cats eventually learn to accept newcomers. Because they are very territorial, the way you go about introducing the new cat can make the difference between success or ‘cat-astrophe.’ The introduction process can take as little as 10-12 days for kittens and very young cats, to as long as 12 weeks for older cats. It all depends on each cat’s personality.
Be sure to give your “first” cat plenty of attention. This will help him feel secure. Confine the new cat to a “safe” room that your current cat rarely visits. Furnish it with a bed, food, water and litter box.
In the beginning, your first cat may hiss and yowl at the cat on the other side of the door. Just ignore him and walk away.
Never punish him, it will only cause trouble between the two cats. Be sure to praise and pet your first cat when he acts calmly when near the new cat’s room.
After a few days, take a cloth and rub it over your new cat as you play with it.
Use a different cloth to do the same thing with your first cat. At feeding time, put each cat’s scented rag under the other cat’s bowl.
This will help them associate the other cat’s scent with something positive. Lots of little feedings each day will help them get used to the smell more quickly. Be sure to renew the scent on the rags each day.