I received this from a Feline Care site: (It's Long)
Suzanne Hetts, Ph.D., CAAB,
The Basics of Feline Social Behavior
The domestic cat is somewhat of an enigma. The cat is a relatively recent domesticate, having been domesticated for only about 4,000 years. In many respects, the domestic cat has changed little from his wild ancestors, especially in comparison to the dog. Shamefully few studies have been done to better understand the cat’s social behavior, and the gaps in our knowledge about normal cat behavior affect our ability to understand, prevent, and modify problem behaviors.
Cats are not small dogs. Their domestication history, social behavior and social structure are very different from canids. Before discussing how we can best help cats in a multi-cat household live as peaceably as possible, we must be familiar with some basic feline social behavior.
Cats have been described as solitary, a term that describes animals who form no lasting groups or pair bonds, but live most of their lives alone. Males and females only come together for mating. Many species of wild felids do indeed fit this description. However, more recent research on the social behavior of domestic cats seems to indicate that "flexible" is a more accurate way to describe their social system.
Cats Have Flexible Social Systems
Some cats likely do prefer to live mostly solitary lives. They do best in single cat homes, and while they may be affectionate to their owners, still retain the stereotypical ‘aloof’ personality. Other individuals seem to be much more social and display evidence of strong social bond formation with other family cats. These cats seem to be ‘best buddies’ – playing together, sleeping together, and spending much of their time in proximity to each other without conflict. However, within the same household, an individual cat may form a friendly relationship with another individual, and an adversarial one with yet another. Unfortunately, it is difficult to predict what will happen when a new cat brought into a family with resident cats. The factors that go into determining feline relationships are complex and poorly understood.
Helpful Hint #1 – Is Another Cat a Good Idea?
Assess the social tendencies of your resident cat. What is the cat’s socialization history with other cats? Does the cat have a prior history of living peaceably with another cat? In general, how social does the cat seem to be? Does he enjoy interactive play? Is he friendly toward human visitors? How does he react if he encounters another cat outside, or sees one through the window? How resilient does the cat seem to be in response to changes in his environment? If the cat seems to be easily stressed, has no history of being socialized to other cats, and doesn’t exhibit tendencies for social interaction, a second cat may not be a good idea. Such a cat may be perfectly content to remain the sole cat in the family.
Structuring the Environment for A Multiple Cat Household
There are a number of important considerations when it comes to meeting the behavioral needs of multiple cats that can help minimize stress and help cats live peaceably together.
Helpful Hint # 3 – Minimize Competition
Structure the environment to decrease competition among the cats. No cat should have to face harassment and threats from another cat while attempting to meet his basic physical needs.
There should be multiple locations, or stations, for all the important things in life. Multiple feeding stations should be provided, so that the cats don’t have to jockey for position at one food bowl.
Lining up several food bowls right next to each other isn’t sufficient – food bowls should be at several different spatial locations, depending on the number of cats and the degree of conflict between them.
Similarly, multiple litterboxes should be provided, in numbers at least equal to the number of cats, perhaps even a one or two more. These boxes should be in different rooms, and even different floors in a multi-level house.
Multiple objects for scratching are also important. Each cat may have individual preferences as to the location and texture of the object she likes to scratch, and these factors should also be taken into consideration. Scratching objects need to be easily accessible, and in areas where cats prefer to scratch. Locating one in the corner of the basement is probably not going to be helpful.
You should also provide multiple cat perches, which allow the cats to use the vertical space to their advantage. Multiple resting places at different heights in various locations should be provided, in numbers relevant to the number of cats in the household.
Cats also need hiding places. Some are provided naturally, such as under the bed, but some rooms may lack them. Putting an upside down cardboard box with one side cut away behind the couch, a small decorative cat screen across the corner of a room, are examples of ways to create hiding places in rooms which have few, or none.
Introducing Cats to One Another
It is never, ever a good idea to just put cats together and "let them fight it out". Because of their lack of submissive behavior, flexible social systems, long arousal times, territorial nature and great individual variation in sociability, such a strategy presents serious initial risks for injury and sets the stage for prolonged, if not permanent social conflicts among the cats. First impressions are extremely important for cats, and an overly ambitious introduction can sometimes require months of behavior modification to recover from.
Introductions cannot progress too slowly. It is always better to error on the side of caution, and assume that the cats may require as much as several months before they can freely be in each other’s presence. Certainly many introductions are successfully accomplished much more quickly, but when owners have an expectation of a more prolonged time frame, they may be less likely to rush things.
In addition to understanding that introductions can be a slow process, you should be prepared for a variety of outcomes. The cats may become best of friends, they may exist with mutual tolerance, they may actively avoid one another with occasional skirmishes, or one or both may be so intolerant of the other that fights are frequent. There are some cases in which the quality of life of one cat is being so negatively impacted by constant harassment from another cat, that finding one of the cats another home may have to be considered. Hopefully, appropriate introductions can help prevent this unfortunate outcome. A protocol for a cat to cat introduction follows.
Helpful Hint # 4 – Cat Introductions
At first, the cats should only be allowed to smell and hear each other, not see or touch each other.
This can be done by confining the new cat to a small section or one room of the house with all the necessities (litterbox, food, water, toys, bed, etc.).
Place towels with the scent of the other cat underneath each cat’s food dish, and on resting places. Rub the cat toys with the scent of the new cat. The goal is to have this scent be associated with ‘good things’.
After the new addition is comfortable in her room (anywhere from several hours to several days), confine the resident cat in this area and allow the new animal to explore the house, under supervision. This allows each cat to become more familiar with each other’s scent.
Feed, or offer both cats treats close to the door to this room (one on each side). This helps each to associate "good things" with the other’s presence. Use "to die for" treats, such as small pieces of tuna, chicken or salmon.
Try slipping one end of a toy underneath the door to encourage the cats to paw at it or each other in a playful way.
Repeat these procedures until there are no aggressive or fearful responses, and both cats begin to show some curiosity about the cat who is on the other side of the door.
Next, wedge the door open, from both sides, about an inch, with doorstops. This allows the cats to peek at each other, paw if they want to, but not have complete access to each other for things to go wrong. Do not progress past this step until the cats can see each other without fearful or aggressive responses. Continue to use toys, food and petting as long as the cats aren’t threatening. Touching an agitated cat may result in a bite.
Next, wedge the door open a little farther, but not so much that the cats can get to one another. Repeat the previous step.
An ideal next step is to give the cats full view of one another behind a screen or glass door before being allowed together.
When the cats are first together, keep the session brief, and continue to offer enjoyable things – food, toys, petting.
If the cats are threatening or fearful when close to either side of the door to the confinement room, offer the tidbits at a greater distance from the door, where both cats can be calm.
Do not move the introduction along too quickly. The cats should be tolerating each other well at each step before progressing to the next. One bout of fighting may set the introduction back for months.
During initial time together, if any hissing or conflicts occur, try to distract the cats into another activity – dangle a toy, get the resident cat into the kitchen with the sound of food preparations, etc. If these reactions continue, back up a few steps in the introduction process.
Avoid having the cats together in a small space, such as a car, until they have become comfortable with each other.
Supervise interactions at home, and do not allow the cats to be alone together until they are consistently demonstrating friendly behaviors with each other for at least a week.
Punishment is rarely helpful with cat introductions as it is counter productive in creating the association of "good things" with each other’s presence.
If a fight does occur, try a loud noise such as an airhorn or ultrasonic device, or a water gun to break it up before either cat is injured. This should be used to interrupt the current interaction, not as a repeated procedure.
Don’t try to pull the cats apart or use interactive punishment. If interactions consistently result in fearful, threatening or aggressive behavior, either the introduction was too abrupt, or this is not a problem prevention situation but instead requires problem resolution.
Keep the resident cat(s)' routine as much the same as possible by keeping feeding, play, and sleeping times and locations the same as before the new cat arrived.