Introducing a new cat to a home where one or more cats already live can typically have three outcomes: It goes off without a hitch; there is slight friction at first but everyone settles in; or the claws come out, the fur starts to fly and the cats look more like prizefighters than affectionate pets.
It's difficult to predict how well cats will share a house perceived as their territory. Some cats may be too territorial to ever adjust to sharing their home with another feline, but more often than not aggressive problems between cats can be resolved with a little time and commitment from their owners.
Even if they don't grow to become feline friends, most cats can learn to at least mutually tolerate each other and coexisting under one roof with a minimal amount of conflict often is acceptable to many cat owners.
Being successful takes some prior planning and a clear understanding of the four main types of feline aggression: territorial, defensive, inter-male and redirected.
Territorial aggression is the most common when introducing a new cat to a home where another cat, or group of cats, already are established.
Cats are territorial by nature, and established animals whether male of female often will view a new cat as an intruder and greet it with hostility.
Their behaviors may be mild, such as just hissing and spitting, or may range to stalking, chasing and full-blown attacks. However, it's important to remember that an introduction is a stressful time to both the new and established animals. An established cat isn't being aggressive just for the sake of doing so.
Also, a cat may not be overtly aggressive to a newcomer, but may still be intimidating it. Since it appears the cats aren't fighting, an owner may be lulled into a false sense that everything is fine. However, monitor the situation closely to ensure that all cats are getting access to food, water and the litter box.
Defensive aggression is at the opposite end of this dichotomy. This type of aggression is commonly displayed by the new cat, since it occurs as a response to a threat whether perceived or real that it feels it cannot escape from.
This type of aggression may be recognized by the typical body postures which accompany it: crouching with the legs tucked under the body, flattening the ears against the head, raising fur, hissing and spitting.
Inter-male aggression also is called male-on-male aggression. Although not as strict as some other animals, cats do maintain a dominance hierarchy known informally as a pecking order and fighting may be in response to cats vying for the top position.
Also, although it may not always be the cause of conflict, female cats being present in the home can escalate inter-male aggression.
Redirected aggression is the fourth form of aggression. It is the most Freudian form of hostility since it often involves displaced aggression on another cat that hasn't caused or provoked the problem.
One animal simply will blame another for some traumatic event, such as a popped bag or broomstick that crashed to the floor.
Redirected aggression can occur when one cat wants to attack another, but can't or won't. Bringing home a new feline can cause established cats to attack each other as a result of redirected fear and aggression they feel for the new animal.
For the same reason, viewing a neighbor's cat through a window often can serve as a catalyst for two housemates to start fighting.
Redirected aggression can be offensive or defensive in nature.
Many steps can be taken to increase the probability of a successful introduction. It's often better to try and prevent aggressive behavior, rather than cope with problems already in full swing.
It can't be overemphasized to take things slowly.
Initially, for the first five to seven days, introduce the new cat to just one room of the house that the other cats don't have access to. Be sure to provide all the necessary accouterments.
This can serve as a "safe area," allowing the new cat to feel secure and providing a way for the new and established cats to smell and hear each other.
During this period, try to further the olfactory exchange between animals. This can be done by taking a washcloth or small towel and rubbing down the new cat, and then putting the towel in a location frequented by the established cats. Do the same procedure in reverse, leaving a scented washcloth in with the new cat as well.
Some authorities recommend feeding the cats on both sides of a door as the next step, but proceed with caution. Cats may play by swiping at each other from under the door, but make certain that it doesn't escalate to aggression.
Dissuade any hostile acts by spraying cats with a water bottle or squirt gun, or by using a frightening noise such as a whistle or baby rattle. This begins to condition the animals that aggression will not be tolerated.
This also works better than direct human involvement, where punishment in the form of a spank from their care giver can lead to redirected or defensive aggression from all cats, or fear and mistrust on the part of the new cat.
Next, try switching locations for a few hours at a time, over a period of several days. This can be performed by putting the established cats in the safe room, while allowing the new cat to become familiar with the rest of the house.
If possible, try to allow a visual introduction between cats in a manner that prevents them from having full physical contact. This can be done by putting up baby gates, or by putting the new cat in a large kennel, or pet carrier, and allowing the other cats to approach.
Even if there hasn't been aggression with the previous stages, allow the cats full contact. Don't put them face to face, though. Allow the cats to find each other. Hissing and growling may occur, but this typical.
At least initially, food and water should be available in more than one location, as should litter boxes. Other recreation items such as toys, cat towers or scratching posts should be abundant enough that cats won't fight over them.
Supervise the situation closely and never leave the cats together without someone being there to monitor them. As with all of the aforementioned stages, slow down or take a step back if cats become aggressive.
Never allow cats to fight it out, or for one cat to bully another. Don't try to pull fighting cats apart, though. Use the water squirting or loud noise methods to separate them. If a cat stops eating or appears ill, discontinue the introduction and bring the animal to a veterinarian to ensure there isn't some stress-induced illness beginning to develop.
Also, contact a veterinarian if after several introduction attempts aggressive behavior persists. Not only can they give advice on how to proceed better, but they may be able to provide medication to aid introduction efforts. In general, spaying and neutering pets can reduce conflict, as well.
Joseph Robertia is a reporter for the Peninsula Clarion. He has worked with wildlife and domestic animals for more than 10 years as a veterinary technician, a zoo keeper, and most recently as a zoologist for the Wildlife Conservation Society. He welcomes any pet-related questions or story ideas, but please none of a veterinary nature. Ideas and questions can be sent to his attention by e-mail at firstname.lastname@example.org.
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