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Integrating Cats

How to Integrate Cats

by Margaret Schill

joliesumnerhugTwo cats cuddling together is such a sweet thing, and the kind of relationship many people hope will be the case when a new cat is introduced to a current cat. While actual hugging sessions are not all that common, slowly and carefully introducing cats leads to most cats learning to get along.

Integrating cats can be a challenge. Adult cats are territorial and do not usually take well to unknown cats suddenly appearing in their territory. The inclination of many adult cats is to act aggressively, (with some outright attacking a stranger cat), to try to make it go away, or to run away from it in fear. Some cats are more aggressive than others. Other cats might be cautious but curious, seemingly open to accepting the other cat.

Various factors can impact how a particular pair of cats will respond to one another. But until the two cats are actually confronting one another, one can't really know ahead of time how it will be. Each pairing is going to be different, since cats are all individuals, with various personalities, histories, and temperaments. The ages of the cats are a factor as well.

Cats need some help from humans to adjust to each other peacefully and less stressfully. Therefore, a slow, carefully managed introduction over many days, or even weeks, sometimes months, is needed to give the best possible outcome. To just plop a new cat in with a resident cat can lead to a disaster.

See the steps for introducing cats below.

Introducing young kittens (under 5 months) to adult cats requires some special considerations, primarily for the safety of the kitten. See Integrating Kittens with Cats for detailed information. Many of the same techniques used to introduce two adult cats are used, but there are also some important differences.

Do note that occasionally, some two cats just won't get along, despite your implementing a slow, careful introduction over a period of months. One cat just might be so overly territorial, or it just might be the wrong pairing for a variety of factors. Sometimes one cat will not abide a certain other cat at all, going to attack it at any chance, but, that same aggressive cat might accept a certain other cat. If after 6 months of carefully trying to get two cats to at least live and let live by following a slow, gradual integration approach, and they still don't, they likely never will. In that case, rehoming one of the cats or having the cats live in separate areas of the home might be the best thing to do. This is referring to aggressive behavior between the cats, not just that they ignore each other or hiss at each other once in a while.


Integration Steps

Take each step slowly, holding onto one step for as many days as it takes for the cats to be ok at that step before moving on to the next step. (A few hisses are ok, but not prolonged hissing, growling or yowling, nor fights.) Rushing things will not make the cats accept each other faster, but will likely wind up making them not get along.

Once things go badly between cats new to each other, it is difficult to get them to go well. If you thought it would be fine to move on to the next step, but the cats turned out not to be ready, simply back track to the previous step for a few more days. Click on the names for each step below to get more details about that step and the reasons for doing those steps.

  1. Isolation: Isolate the new cat completely for a few days, and especially until the new cat has been examined by a vet to be checked for any illnesses, diseases and parasites. The new cat also needs time to calm down and get used to being in a strange place, as well as getting used to the new people, before he or she is in a good frame of mind to meet other cats.
  2. Scent Familiarization: Scent familiarization with items, such as towels, rubbed on each cat, then left in the area of the other cat, while the cats are being kept separately. Petting one cat and then letting the other cat smell the scent on your hand is also helpful.
  3. Visual Familiarization: Seeing each other with no physical contact, such as from a slightly cracked opened door, or in a large carrier, a few times a day for a short time period (stopping if there is prolonged hissing, growling or other aggressive behaviors). This is done along with Scent Familiarization.
  4. Room Swapping: Switching the cats' places for a while every day, with no physical contact between them. This is added to doing Scent Familiarization and Visual Familiarization. Room swapping lets the new cat get used to other areas of the home without worry about the other cat, but it also winds up resulting in better scent familiarization, as each cat will smell the scent of the other cat more through out the rooms, and in a natural way (as opposed to the towel left lying around as done at first).
  5. Developing Positive Associations: Start developing positive associations with no physical contact, such as by feeding the cats tastly canned food or treats on opposite sides of a door when cracked opened and even when it is shut. Continue with the above steps as well.
  6. Short Supervised Visits: Brief, highly supervised visits paired with food or treats to allow the cats to pair something postive with the other cat while the other cat is in view in the same area. Do not place the cats next to one another, but rather merely in the same room a somewhat far distance apart so they can freely, or not, approach one another. Do not allow any fights or one cat to chase the other. Calmly separate the cats when things start to go badly. These short visits need to be kept positive in order for positive feelings to have a chance to develop between the cats. Continue with Room Swapping, but Scent Familiarization and Visual Familiarization can be discontinued.
  7. Separation Signs of Hostilities: Separate the cats at signs of hostilities, or great fear. Learn cat body language to tell when a problem is starting. Click on the name of this step to read about cat body language and to see some pictures.
  8. Longer, Carefully Supervised Visits: Mingling under very careful supervision for up to a few hours, before total separation again. Adjust the length of time depending upon whether there are any signs of hostilities or stress, but no matter how well things seem, do not yet permit 24/7 free mingling. Continue with Room Swapping.
  9. Limited Free Mingling: When the above have gone well, free mingling except when the people are not home or asleep, so quick intervention can be done if needed.
  10. Free Mingling Full Time: The cats are let together freely all the time when all the above steps have gone well. Backtrack to the limited mingling if the cats weren't quite ready to be together all the time.

Stay on each step for as many days, weeks, or even months, as necessary for your particular combination of cats. Some cats take longer to adjust to a new cat than some other cats will.

You may come across advice saying to ignore the new cat in the presence of the resident cat so that the resident cat doesn't get upset. Do not do that. If you ignore a new cat in front of the resident cat, it can make the resident cat feel you don't really care for or want the new cat there either. It also makes the new cat feel unwanted and uncared for. It is good to show some attention to the new cat in the presence of the resident cat, but don't go overboard. When you take in a new cat, you need to feel as much loyalty and concern for that cat, and worry just as much about how the new cat feels as you do your first cat.

The whole of this article goes into more detail than many others do. This greater detail is especially helpful if one cat that you are trying to integrate is on the more territorial, aggressive side; if one of the cats is on the more fearful, defensive side; or if there is a large disparity in age range. And, simply, if you want all the nitty gritty details not usually included in articles on introducing cats.

Step #1 Isolation

To start with, the new cat should be set up in a separate room, often referred to as a "safe room". No other animals should be allowed in that room at first. The safe room needs a litter box, food and water bowls, scratching post and flat scratching mat, toys, a comfy sleeping spot, and some place the cat can hide behind or under. If there is a bed in the room, put things under it in the center so that the cat can be reached if need be, (such as an emergency or vet appointment), but also so that if the cat is a timid, fearful cat, it doesn't develop the habit of mostly staying hidden away unseen and unseeing what is happening in the room. A cat carrier, with the door of it wedged open, or a small box on it's side can be used as a "hidy spot". A window view in the room is preferred, but only open it a crack as cats can push out or rip some types of window screens.

If one has taken in a tame stray from the streets, the first day and night in the house can be a bathroom or other room with no carpet, so any spraying or urinating on the floor can be easily cleaned, and so that if the cat has fleas, there won't be a problem with flea eggs being embedded in carpet. Once the cat is using the litterbox, and has had a flea treatment applied if necessary, a more suitable and comfortable room should be used for the "safe room". (Note: If after a full 24 hours the cat has not urinated anywhere, take him or her to the vet as the cat might have a urinary blockage, which can kill the cat in as little as 24 hours from the time you realize something is wrong. If the cat is seen trying to urinate but nothing or almost nothing comes out, or just drops of blood, get the cat to the vet immediately.) Homeless cats who never used a litter box will hold it for a long time, not wanting to soil the area. It can take them up to 24 hours before they decide to use the litter box, which they were not sure was the correct place to eliminate.

If the new cat has not yet been neutered, that should be done during the isolation period so that hormonal influences are out of the equation of the meeting of the cats. Since the cat isn't used to free roaming the house yet, he/she won't be as upset about being confined to one room during the recovery time after surgery as a cat used to free roaming the house would tend to be. One would also want a male cat's hormones to have some time to lessen to reduce the chances of territorial spraying and lessen aggression responses due to high testerone levels.

Aside from the need to keep a new cat separate at first from the resident cats due to cats needing a slow pace for the best chance for peaceful integration, it is very important health wise. The new cat needs to be tested by a vet for Feline Immunodeficiency Virus (FIV), Feline Leukemia Virus (FeLV) and checked for any other illness and parasites, including intestinal parasites, before being allowed to have contact with the resident cats or sharing of food and water bowls, and litter boxes. There are no cures for FIV or FeLV, so one really needs to know the status of all new cats before allowing any contact with other cats. (However, cats testing positive for FIV and FeLV do not need to be euthanized if they are not suffering. Cats with FIV and FeLV can live symptom free for many years as only cats or with other cats who have the same condition.)

Even if the cat was examined by a vet as soon as you got him/her and tested negative for FIV and FeLV, an incubating illness would not be able to be diagnosed yet. The new cat should remain isolated for several days to allow you to notice any signs of a respiratory or other illness that might take a few days to manifest if the cat acquired it just before you took it in or adopted it from a shelter, or other person.

The time spent in the safe room away from the other cats is important also to allow the new cat to settle down and start to relax. It is very frightening for cats to be uprooted from their territory and all they have known, to then be placed somewhere new, especially when the scent of other cats is present. Territory is highly important to cats, and new territories can be potentially dangerous. The new cat needs time to get his/her bearings and feel a degree of safety, as well as feeling the new home is now his/her home, before he or she is in a state of mind to take on meeting other cats who could possibly be hostile.

The new cat also needs to start to feel safe about the new people to where they allow handling before being allowed to mingle with the other cats. During the introduction process, there may be times when it is necessary to pick up and put the new cat back in his or her "safe room". The new cat will feel more secure meeting the resident cats in your presence if you and the new cat have bonded.

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Why have more than one cat?

It can be better for many cats to not be the only cat.

In nature, cats are not the total loners it is sometimes thought they are. Although they are territorial, they do have some friendly social interactions with certain other cats.

Indoor only cats often get bored and lonely in homes where the humans are gone for many hours a day. A companion cat can help relieve those feelings - provided they get along!

The younger the cat is, the more important it is for there to be another cat, preferably one near the same age. Cats under a year old especially benefit from having a companion cat. Not only do young cats like to play with other cats, but they learn social skills and comfort one another.

Of course, one needs to introduce cats slowly, as per the guidelines in the article on this page, for the best outcome. If both cats are under a year old, the free mingling point is reached sooner than when the cats are older.

Try to avoid pairing kittens with older cats. Older cats do NOT want to play all the time like kittens do, and you will more likely wind up with a frustrated kitten and an irritated, stressed older cat.

Litter box Needs

A new cat needs a new litter box. See a wide selection of litter boxes by clicking here.

Click here to read about litter box guidelines especially for homes with more than one cat.

Multi-cat introductions

In the case of multi-cat homes, EACH cat needs to have gone through the introduction steps with the new cat.

It is sometimes erroneously thought that when the resident "alpha" cat accepts the new cat, the other cats will "fall in line" with acceptance.  This is NOT true

Cats are not pack animals like dogs and do not follow a strict hierarchy, following the leader.  Cats are independent individuals, and each decides to accept or not another cat.

Often, it turns out that the "non-alpha" cats are the ones to quickly and relatively easily get along with the new cat, since they are not very concerned with being the "alpha cat". So therefore, they don't feel a newcomer is much of a threat to their position.

What are often termed "alpha" cats are frequently more high strung, territorial cats who really have some fear behind their aggressiveness towards other cats.  When such a cat sees all his other housemates feeling fine and content with the new cat, that can help make the "alpha" cat feel it's ok.  Not always, though.

Cat in Isolation tested positive for FIV

This cat, Bruce, tested positive for FIV while still in comfortable isolation, before introduction attempts with our other cats were made. Keeping new cats isolated until they get checked by a vet is important.

Read about Bruce here.

Read about FIV here.