Introductions between cats can be simple, complex, or in some cases impossible. Often when cats are young they are not properly socialized with other cats making them less familiar with the idea of sharing, playing, smelling, or even seeing other cats. The other issue is that cats are not pack animals. Cats establish a hierarchy; there is an order from top cat to lowest cat. If a household cat feels they can move up the hierarchy, they will challenge other cats in attempt to become top cat. This could be behaviours like stealing preferred sleeping spots, trying to steal food from each other, or occasional very short swatting when passing each other. However for some cats this behaviour escalates to an inappropriate, dangerous amount of fighting. Household cats should never be allowed to “fight it out”. Fighting will worsen the bonds between the cats, making it harder or impossible for them to get along again.
Introducing A New Cat (From the American Association of Feline Practitioners – Cat Friendly Practice)
Introducing a new cat into a household, especially when there are existing cats, can seem like an overwhelming task. Patience is the key. The transition can take several weeks but planning ahead can reduce the stress, allow for an easier transition, and build a positive relationship between your feline companions.
The first few days you should isolate your new cat in a separate room with its own food, water, litter box, bedding and toys. Bring familiar items from the adoption location in order to make it smell comforting and “homey” for them. Keep the carrier open in the room as well so the cat has a place to hide and also becomes familiar with it for future veterinary visits. This is important as we know that many cat owners become stressed because it is often difficult to get cats into carriers if they are not habituated to it. If there are other cats in the home, this allows both cats to first get used to the scent and sounds of the other cat without risk of confrontation. Be sure to spend a lot of time with each cat or group of cats individually.
Once all cats in the home seem relaxed, gradually start to move the food dishes closer to the door that separates them. If any stress is noted, go back to the step where they were comfortable and work more slowly. You can also use a toy for them to play with under the door when they are calm and hopefully curious. If cats are calm, take a cloth/blanket to wipe one cat and then put that cloth in the room with the other cats. Do the same for new and existing cats, so that the other can smell the cat in their area. If this is comfortable to all cats, you can also mix the scents on one cloth, wiping first one cat, then the other. Reward all calm behaviours with treats and praise in a soft voice.
When the cats are comfortable with the above, it is time to try a brief and safe interaction. This can be done by opening the crack of the door an inch so that both cats are safe, but can start to see each other. If one cat hisses or tries to attack, close the door and back up the process, and restart more gradually. Sometimes it can be helpful to distract the cats with food. An eye and hook latch or doorstops on each side of the door work well.
When all is going well, place the new cat inside a carrier and allow the other cat(s) to explore by seeing and smelling the new cat more closely in a safe environment. Continue to reward calm behaviors with treats and praise in a soft voice. If the cats are harness and leash trained, this is another option.
If the cats seem comfortable in this environment the next step is to try placing them in the same room with direct supervision. Start introductions for brief periods making it more likely that the experiences will be positive. Remember to be patient and go back a few steps if necessary and gradually re-introduce. If you have any concerns, contact your veterinarian. If your cats have been successfully acclimated, remember that each cat still needs their own resources, often in different locations, such as food, water, bedding and litter boxes.
It can still be overwhelming to introduce a cat into a home without other cats. As your companion becomes more comfortable, he or she will be more likely to explore and test the boundaries. You should always check for potential hazards such as poisonous plants, full-length curtains, fireplaces, breakable objects, etc. The more prepared you are, the smoother the transition can be.
Development of Aggression Between Housemates
As cats mature their relationships with each other can change. This could cause previously friendly cats to become aggressive towards each other. Other household changes can affect cats at any age such as; people coming or going, moving, renovations, changes in preferred sleeping, perching and eating areas, medical changes, redirected aggression, and territorial aggression.
When household cats start fighting it can take a few hours or several weeks for them to “recognize” each other and re-establish a compatible relationship. During this time each cat should be provided with lots of space, perches, litter boxes, as well as water and food bowls out of sight of each other. If fighting is intense then the cats will need to be separated and a formal re-introduction the same way as you would introduce a new cat to the house should be performed.
It is important to figure out why the cats started fighting, and confirm there is not an underlying medical condition that will need to be treated before re-introduction can be successful. In some cases behavioural medications will be needed to help decrease defensive posturing, vocalization, fear and anxiety.
During times of aggression it is important not reward unruly behaviours. If the dominant cat is stealing food from the other cat it needs to be taken away immediately. Swatting and fighting is not acceptable and should be disrupted immediately. Loud noise such as coins in a pop can, a firm “no”, or even a horn can be used to startle and stop the fight. In the case a severe fight, use extreme caution as cats often mistakenly hurt their owners while trying to get each other. These cases it is best to throw a thick blanket over the cats and separate them to other areas to calm down.
Fighting between household cats can be scary and your veterinary team is always available to help. Any fighting should not be taken lightly and a behaviour consultation with your veterinarian is the best place to start.
Products Available to Help Multi-Cat Households
Medi-Cal Royal Canin Calm Diet – Calm Diet is a veterinary specially formulated to assist in the management of stress and anxiety in cats. It is formulated with milk protein, tryptophan, and nicotinamide to help create a calming effect. It also promotes skin health to help cats look healthy. A poor coat quality can sign of weakness between cats, such as they are no longer able to groom or have an underlying medication condition making them an easier target.
Zylkene – This veterinary supplement can be given daily to cats to help reduce stress and anxiety. Zylkene contains casein, a milk protein that is known to promote relaxation in newborns after breastfeeding. Cats can be difficult to give medications to, however this medication can be opened and sprinkled over food or mixed with water or tuna juice to aid in administration.
Feliway – Feliway helps comfort and reassure cats by mimicking the natural feline facial pheromone that happy cats use to mark their territory as safe and familiar. It is an innovative, non-drug option for stress-related problems in cats. When cats feel comfortable in their environment they run their cheeks up against walls, furniture, and even their owners. This leaves a message, undetectable to humans known as feline facial pheromone. This pheromone reminds cats that their environment is safe and familiar. This product is available in a spray that you can use on their favourite areas (litter box, sleeping areas), or a diffuser that work like a plug in air freshener to disperse the product in common areas. The diffuser lasts a month, then you can replace the Feliway liquid without repurchasing the plug in part of the diffuser.