Cat - Reintroduction following Hostile Interactions

What is the best way to safely reintroduce a cat into the household?  

If problems of aggression have broken out between cats in the same household it may be necessary to use an active programme of reintroduction.  In order to maximise the success of the programme it can be helpful to install Feliway diffusers in the house as part of the treatment approach.  These diffusers should continue to be used throughout the reintroduction and should be left in situ (being replaced once a month) for at least a month after you consider the process to have been successful.

Will temporary segregation be required?

If active hostility exists between cats it is usually advisable to temporarily segregate them prior to attempting a reintroduction process.  Confine your cats to different parts of the house with their own essential resources.  This allows both cats an opportunity to adapt to the smell and sounds of each other, without the possibility of direct contact or physical confrontation.  If it is possible to house them in rooms with a glass door between them, it may be possible to allow your cats to see each other through a safe partition.  When your cats show no fear, anxiety, nor threat towards each other, you can progress to controlled exposure exercises.  However, if hostility has been pronounced the use of a glass partition in the early stages of segregation may not be advisable as it could allow rehearsal of hostility which will then limit progress later.

Will it be necessary to confine one of my cats during reintroduction?

Depending on the level of hostility prior to the reintroduction it may be advisable to confine one of your cats to an indoor pen or to restrain him on a body harness (which needs to be introduced appropriately in the absence of the other cat) and lead before attempting any increase in proximity to one another.  In some cases it may be necessary to restrain or confine both cats as this will ensure that neither can escape, and thereby set off a cycle of run and chase, nor injure each other.  However, it is best to keep restriction to a minimum.  If both the cats have been in indoor pens during the first training session, you can go on to switch them around and place them in each other's pens at the next session (so that they are exposed to each other's scent).

Is scent transfer between the cats or other products helpful?

As well as using Feliway diffusers in the home it can be helpful to rub the cats with towels that have been rubbed over the other cat and switch from one to the other to further mix their scents.  Felifriend is a product which is advocated for use in the introduction of cats but clinical experience suggests that it is more likely to be successful in initial introductions between total strangers or in introductions of cats which have been temporarily separated but were in a positive relationship prior to that separation.  The use of Felifriend in situations of trying to reintroduce cats where hostility has already occurred is generally not advisable.

What can I realistically hope to achieve?

The aim of this introduction is not to bring your cats into close proximity or to persuade them to like each other but rather to reach a situation of neutral tolerance where both cats can co-exist under the same roof.  Do not attempt to move the pens progressively closer as this defeats the purpose of the introduction.  Instead work to the point where both cats can be loose in the same room, with the pens present at a reasonable distance from one another so that they can act as a retreat location for each cat should that be needed.  Do not work toward bringing your cats together to eat next to each other as cats are solitary feeders and being made to eat in close proximity to each other can be stressful.  Cats should be fed alone and food should only be used as a distractor when the other cat is at some considerable distance from it.

How can I develop positive associations?

A rewarding activity such as eating treats can be used to establish more positive associations but your cats need to be far enough apart that they are relaxed and will take food while in the presence of the other cat.  It is really important that the distance between your cats is significant during this process since the idea is not to get your cats to eat together or to move their food bowls nearer to one another.  The food is simply used as a focus for your cats to concentrate on, rather than taking notice of each other.  If your cats will not eat then they are probably too anxious and too close together so try moving the cats further apart.

Another way to integrate cats is with play therapy.  Some cats are more interested in play, toys or catnip than they are in food.  One of the best toys is a wand type or fishing rod type handle with a stimulating play toy such as a catnip mouse or feathers on the end for chasing and pouncing.  Begin by having both cats play at a significant distance from each other.  Once again the aim is not to bring your cats closer together and get them to play together but to help them to relax in the presence of each other so that they can develop a tolerance that is workable within the same household.

What territorial space is required for each cat during reintroduction?

Whilst carrying out the active reintroduction procedure it is also important to ensure that each cat has access to a distinct safe zone in which to eat, drink, sleep and play.  In addition the availability of safe and secure toileting locations needs to be considered and this is particularly relevant if your cats are not able to access outdoor latrines.  Each cat should be able to access their essential resources whenever they need them and therefore the provision of distinctly separate feeding stations, watering holes, resting locations, play areas and latrines is an essential part of the treatment plan.

What if aggression persists between the cats?

Despite slow and careful progression with the introduction process and the provision of separate living quarters, or core territories, some cats may continue to display aggression. If your cats get along at certain times of the day, you may consider providing limited exposure and interaction at these times and using a lead and harness to enable you to safely separate the cats should any aggressive displays emerge.  If the problem is too severe, it may be helpful to medicate one or both cats on a short-term basis and this option should be discussed with your veterinary surgeon.  If longer term treatment is being considered the welfare implications of this approach must be taken into account.  If everything has been done to try to establish separate territories for your cats under the same roof but without success then it may be necessary to accept that the cats will never be compatible housemates and that the only way to avoid hostility is to find a new home for one of them.