Introducing another Adult Cat or Kitten to your Cat

It is always going to be potentially difficult to introduce a new cat to your resident cat. It is important to recognise that even when the introduction process is conducted as carefully as possible, this is not a guarantee that the cats will happily accept one another. Some cats simply do not want to live with other cats and it is important that you are able to recognise and act on this in order to ensure the cats in your care have the best welfare possible, both in terms of thinking about their physical health and their mental wellbeing.

Reading ‘Thinking of getting a cat?’ will help you decide whether your home and lifestyle are able to support another cat effectively.

Your cats may live with you for many years. Getting the introduction right and taking extra time if necessary to carry it out could make a huge difference to their perceptions of each other. Not only do owners feel much better if their cats get on rather than disliking each other, but also the cats’ stress is reduced considerably.

Setting up the home for your new cat

If you have made the decision to get a new cat, the first step when you bring it home is to confine the new cat to a single room. Ideally, pick a room that your resident cat does not use much and that you do not need constant access too, perhaps a spare bedroom or study.

Ensure the new cat’s room contains:

• Food
• Water
• Comfortable resting areas with bedding
• Hiding places
• Litter tray
• Toys
• Scratching post

These items should be those that came with the cat, or brand-new. It is not a good idea to use some of your resident cat’s belongings as these will smell of your resident cat, which may make your new cat uneasy at a time when you are trying to help it to feel relaxed in its new surroundings. Likewise, reducing the number of belongings your current cat has (eg, the loss of a litter tray) has the potential to cause it distress.

In addition, the use of synthetic feline facial pheromone Feliway Classic in both the new cat’s room and in the area where the resident cat spends the most time will help to create feelings of familiarity and security within the physical environment. For the new cat, this may help to speed up adaption to the new environment and, for the resident cat, it may help prevent any feelings that its territory is being threatened.

Give the new cat plenty of time to become accustomed to the routines of the new home and the people that live within it, and to allow your new cat’s scent to become part of its room. This will occur:

• Actively by your cat rubbing its scent gland areas on its face against furniture and the corners of the walls and by scratching its scratching post
• Passively by your cat sleeping and resting on bedding and playing with toys

Depending on the cat, this acclimatisation period could vary from several days to a week or two. Signs that your new cat is comfortable with its new environment include:

• Friendly behaviours when you enter the room such as approach, rubbing around your legs, chirruping, purring and meowing
• Resting on its side with belly exposed and rolling over
• Playing with its toys
• Facial rubbing on furniture, corners of walls and other items in its room
• Normal eating, drinking, grooming and toileting behaviours

If your new cat is showing any signs of being frustrated (see below) at being kept in a single room, you may wish to provide it with more space such as a corridor or additional room that your resident cat does not access. If this is not possible, it may be advisable to start the introduction process earlier.

Signs of frustration at being confined include:

• Scratching or pawing at the door and surrounding area, or at the windows
• Meowing for several minutes at a time
• Pacing by the door
• Rearing up at the door
• Swiping at you when you try to leave the room

Scent swapping

Once the cat is fully comfortable in its own part of the home, it is time to begin the process of introducing the cats to one another. Start by gradually introducing the scent of the other cat to each cat (without actually physically meeting). This is essential as cats use the scent of individual cats to recognise whether they are in the same social group or not. Our aim is for the cats to recognise one another as part of the same social group by creating a communal scent.

The idea behind scent swapping is that both cats become fully comfortable in the presence of the smell of the other cat before physically meeting. By ensuring this, there is a greater chance they will accept the physical presence of one another as they are more likely to consider each other as part of the same group. For more information on the way cats communicate with each other using pheromones and scents, click here.

Step 1: Exchange bedding

Begin scent swapping by taking one piece of each cat’s bedding (eg, a single blanket) and placing it in one of the other cat’s beds. There should be ample bedding for both cats so that this change in bedding does not leave either cat with limited sleeping/resting sites. It is hoped that each cat will rest upon the bedding of the other cat, thereby mixing their two scents to create a communal scent. Quietly observe both cats’ reactions to the bedding. A cat that shows negative behaviours towards the bedding such as actively avoiding it or even hissing at it may be less likely to accept a new cat into its home and therefore will need to progress through the steps at a much slower pace.

Once the cats are showing relaxed behaviour in the presence of the bedding, the bedding can then be replaced back into the original cat’s room to allow further mingling of scent. This process can be repeated for more than one piece of bedding.

Extra tip: It is always a good idea, if possible, to try and obtain some bedding from your new cat before you bring it home so that you can gauge your resident cat’s reaction to the new cat’s scent as early as possible. If the resident cat accepts the smell of the new cat before it is physically in the home, then it may have a better chance of coping with hearing, seeing and smelling (at a greater concentration) the new cat when it does come home.

If the cats enjoy being stroked, then a light cotton glove can be worn while stroking the cats (one glove for each cat) or a cloth wiped over each cats’ facial glands (under the chin, cheeks and areas in front of the ears) and then wiped onto the furniture in the part of the home the other cat lives in. This will allow further scent exchange and the opportunity for the cats to facial rub on top of the marks and create a communal scent.

Step 2: Allow exploration of each cat’s area

If the cats show no adverse signs to the smell of one another on the bedding (and on the rubbed areas) then, as an additional step, the resident cat could be briefly confined (for example, during the night the resident cat could be confined to the owner’s bedroom) to allow the new cat to inspect the resident cat’s area of the home. Confinement should only occur, however, if it is unlikely to cause any distress such as frustration. Conversely, the new cat could be temporarily removed from its room (and confined elsewhere) to allow the resident cat to explore the room. It is recommended that the latter occurs only when the new cat is entirely relaxed and therefore this is unlikely to be advisable until several days after the introduction of the new cat.

Step 3: Allow visual contact

The cats should only be allowed to see one another once they are fully relaxed in the home in general and when encountering the scent of the other cat. Being able to see each other should happen through a physical barrier. This can be achieved in a number of ways including:

• a door held slightly ajar (so they can’t pass through)
• a mesh barrier – some people make a wooden door frame that fits within their existing door frame that is covered in mesh wire
• a children’s stair gate

Advice for using crates positively for kitten introductions only

• Crates such as those designed for dogs should never be used for adult cat introductions as the small space of a crate restricts their ability to escape from the other cat. However, if a kitten is accustomed to a crate during its early rearing or you have positively trained your kitten to enjoy being in a crate, then it may be possible to use it in introductions if your home does not have separate rooms or cannot be divided by other means. Never introduce a cat or kitten by confining one or both to a cat carrier – they do not provide any opportunity for retreat.
• For kitten introductions, a large crate can be used in a room, positioned in the corner and partially covered with a blanket to provide an area for the kitten to be out of sight.
• As well as a blanket concealing one area of the crate, the crate should also always contain a hiding place within for the cat to remove itself from visual view. This could be provided by placing a cardboard box or igloo bed in the crate. This allows the kitten somewhere to hide if they are anxious when the resident cat approaches.
• The door to the room can then be opened and the resident cat allowed to explore with the kitten in the crate. The kitten can be distracted with some treats or high value toys and the resident cat can be offered a high value food treat also to reinforce positive associations. These treats are best reserved for those times when the two cats are exposed to each other to maintain their value.
• Crates need to be large enough for the kitten to be able to move around easily and need to contain key resources such as food, water, a litter tray and a hiding place. These resources need to be positioned as far apart from each other as possible and thus the bigger the crate, the better.

Being in the visual presence of one another should be associated with pleasant feelings. Thus cats can be played with or fed food treats, both activities occurring separately. It should never be a staring contest. Instead, the cats should be happy going about their own activities while being able to glance at one another. If they wish to sniff each other through the barrier, allow this but any sign of negative behaviour to one another (eg, growling, hissing, flattening or rotating of ears with tense body posture) should be instantly distracted, for example by luring the instigator of the negative behaviour out of sight of the other cat using a toy such as a fishing rod toy. Cats should never be punished for showing negative behaviours to one another as this is only likely to frighten the cats more.

If there is more than one resident cat, visual contact should initially occur between just two cats (one resident each time and the new cat) and then progress to more cats (more residents and the new cat).

Keep the sessions short and finish while they are still doing well, that is, interested in the food/toy provided and showing no negative behaviours or signs of distress. If either cat shows any signs of distress or negativity towards each other, separate the cats physically and visually immediately.

Synthetic feline facial pheromone Feliway Friends (Feliway Multicat) can be used if any conflict arises between the cats during introductions or a breakdown in their relationship happens later on in the process. This can help the cats feel more comfortable around each other again. The diffuser should be plugged into the areas of the home where the cats spend most of their time or areas where the conflict or tension occurs most frequently (once the cats are spending more time together). Feliway Classic and Feliway Friends can be used together in these cases.

Step 4: Physical access but supervised contact

This next stage should only occur when cats are fully comfortable with seeing one another through a barrier. Removing or opening the barrier should happen quietly, ideally at a time when the cats are both engaged in a pleasurable activity such as play or feeding. Never force the cats together and try to observe passively. The main aim is that the cats are comfortable with the presence of one another; they do not need to be physically interacting. If the cats show any signs of negativity towards one another or any signs of distress, replace the barrier to separate the cats and go back a stage. If cats appear to be relaxed in the company of one another, then physical supervised access should be as frequent as possible.

Step 5: Free access without supervision for short periods

Free unsupervised access for short periods of time (a few minutes) can occur as long as there is no negative behaviour between the cats during the ‘physical access but supervised contact’ stage. Once commenced, free unsupervised access should be as frequent as possible. At other times the new cat is still kept separate. If friendly behaviours are seen between the new cat and the resident, they can be kept together for increasingly longer periods although always make sure they have access back to their own parts of the house. At this stage, it is particularly important that each cat has its own resources in separate locations from each other (ie, not all in one room) and from the resources of the other cat(s) in the household as this will help prevent the cats from feeling in competition with one another.

With time, if things are going well, the separate room can be kept permanently open and the new cat and resident cat(s) are free to come and go as they please. In some cases, however, where some conflict begins to show, a separate room or other restricted area (eg, accessed through microchip operated cat flaps) can be made available to a single individual or individuals that do get along well, allowing cats to access the whole environment but also to retreat to areas in the absence of the cats they show conflict with. Additional opportunities for utilising vertical space such as shelves, walkways and perches can help cats to maintain their own space. The key point is to continue to monitor, as relationships between cats can change over time and between different contexts and adapt according to the cats.

If you are struggling to successfully complete this introduction process or the cats experience a breakdown in an initially good introduction, it is a good idea to seek professional help. Contact your vet who will be able to provide you with advice or refer you to a qualified behaviourist.