Inter-Cat Aggression

Aggression is the number two feline behavior problem reported to behaviorists, second only to inappropriate elimination. Cats show several different types of aggression including status-related (dominance) aggression, fear aggression, territorial aggression, and redirected aggression.

Territorial Aggression

By nature, cats are solitary hunters, not pack animals. However, when food is plentiful, as it is in most of our homes, a group of cats can often live harmoniously, at least most of the time. But even well fed cats retain their instinct to define and defend a territory. Outdoor cats mark their territory with urine, feces, and various natural odors (so-called “pheromones“) from various scent glands. Scent marking serves to indicate that the territory is occupied and reduces encounters between cats.

In close quarters, though, cats often live by certain subtle territorial rules, respecting distinct territories within a single room, like access to a particular couch or favored window perch. Moreover, some feline housemates learn to “time share” these favored locations with one cat taking the front window in the morning and the other taking it over in the afternoon.

Unfortunately, anything that disturbs the established “rules” can lead to confrontation, and what starts as occasional minor spats of aggression may erupt into a full-blown feud unless precautions are taken. It is important to keep in mind that when cats are confined indoors they have little chance to avoid each other, and aggression, once it occurs, is often compounded.

Problems with territorial aggression are most common when a new cat is added to the household. If sudden introductions lead to aggression, this can set the stage for future battles and may not bode well for the future. The way to circumvent this problem is to gradually introduce unfamiliar cats to each other across a closed door. A gradual introduction of a new cat to the household may take two to three weeks. This said, if initial animosities are mild, they often resolve spontaneously over a period of four months, even without such precautionary measures.

Territorial aggression between cats in the same household tends to develop gradually. The more confident cat may begin to guard various resources and threaten its feline housemate over the slightest infraction. Gradually the threats may progress to attacks and the victim may become progressively more frightened. Depending on the victim’s temperament, he may choose to retaliate or hide, only making an appearance when the territorial cat is not around. Occasionally litter box problems may arise because the fearful cat is too afraid to leave his hiding place. Additional problems of spraying and other forms of marking may occur if both cats are of close to equal status.

Non-Recognition Aggression

This explosive type of aggression occurs between feline housemates that have previously had a reasonable relationship. It probably occurs through “failure of recognition.” Non-recognition is most often triggered when one cat in the family is brought back from the veterinarian’s office, or the groomer, and smells and behaves differently. If a fight ensues, it can damage irreparably the relationship between the cats and lead to the development of territorial aggression. It is best avoided by separating indoor cats after outside excursions until it can be established that they are friendly toward each other.

Redirected Aggression

Aggression intended for an outdoor intruder that is redirected onto a feline housemate can also severely damage the social bond between cats that have previously cohabited in harmony. A typical scenario is of one cat resting by a window when a second cat sees an intruder cat outside the window and rushes to attack it. A sudden conflagration ensues with both cats fighting with one another. Theories as to who first attacks whom vary. One theory is that the would-be attacker, behind the window, being unable to attack the unwelcome visitor on the other side of a window, turns and attacks the cat next to it instead. This is true “redirected aggression” and is analogous to an angry man who punches a wall.

A second possible scenario is that one of the inside cats becomes extremely frightened by its buddy’s aggressive display (intended for the cat outside) and adopts a defensive posture with its pupils dilated, claws unsheathed, crouched body posture, ears flattened, and perhaps hissing and swatting. The other cat observes this display, interprets that it is about to be attacked, and takes the offensive. A fight ensues.

A variation on the theme of redirected aggression occurs when two cats are resting in the same vicinity when a frightening incident occurs, such as an unusual and particularly loud noise. Both cats are startled and assume a defensive posture. When they see each other in this stance, they each assume the other is ready to launch an attack. Each cat responds defensively, a fight erupts, and they remain fearful and aggressive toward each other afterwards.

In cases of redirected aggression, the cats should be separated immediately. If this is done and they are given several hours, if not overnight, to cool off you may be able to reintroduce them the next day over a bowl of food.

General Recommendations

• Neuter all cats.
• Keep nails trimmed as short as possible to lessen the chance of injury.
• Set aside 10 to 15 minutes every day for each cat for interactive playtime. Encourage continuous aerobic play with laser pens, feather wands, or toys on strings to reduce anxiety and release energy.
• Place bells on the cats so you can locate them. The bells must be loud and have different tones allowing you to distinguish the cats. This will also allow the cats to know each other’s whereabouts so there will be less chance for a surprise attack.
• Rub each cat daily with a towel that has the other cat’s scent to familiarize each cat with the other’s scent.
• Treatment with facial pheromones may be helpful. These pheromones are thought to have a calming effect and are associated with pleasurable experiences and “friendly cats.” A product called Feliway that contains facial pheromones is marketed to discourage urine-spraying behavior in cats. While Feliway is not suitable for direct application to the cat (because it is in an alcohol base), a small amount may be sprayed on a cloth or tissue and then rubbed onto the cats once it has dried. Alternatively, you can gently rub the bald triangular areas between the cat’s eye and ear with a tissue and apply that to the other cat.

If cats end up in a fight, do not reach between them as you could be injured. Instead, separate them with a blanket, broom, or whatever is handy. Alternatively, make a loud noise to startle them by dropping a pan or book. Cats become extremely agitated after an aggressive event and respond best to isolation until they become calm. You should banish the aggressor to a less desirable area. Cats may need to be separated for as long as 12 hours before they calm down and it is safe to reintroduce them.

Counter-conditioning and Desensitization

A systematic desensitization and counter-conditioning program can reintroduce feuding cats. Systematic desensitization gradually accustoms a cat to something he fears or is uncertain about. Counter-conditioning rewards the cat when he is in the presence of his “enemy,” with something he needs or wants, such as food or attention. Over time, these techniques work together to make a formerly stressful experience pleasant and rewarding.

Time is the key word here. Desensitization can take months and will require considerable persistence and patience. Throughout the process, owners must be prepared to return to the previous stage at the first sign of hostile behavior before advancing to the next stage of exposure.

Neither cat should show anxiety or aggression during the reintroduction process. If they do, go back to a distance (or level of exposure) at which both cats are comfortable. Look for signs of anxiety from the victim and aggression by the aggressor. Signs of anxiety may include not finishing the food, eating quickly and leaving, avoiding eye contact, hiding, or trembling. Warning signs of impending aggression include staring, tail switching, flattening of the ears, growling, hissing, and stiff body posture. Banish the aggressor to another room if this behavior is observed.

Reward the cats for ignoring each other. If the aggressive cat averts his gaze, he should be rewarded immediately. If the cat that has been attacked makes direct eye contact with the aggressor, reward that response. Do not give food treats or praise to either cat for showing fear or aggression; Reward only positive interactions between the cats.

Steps to Follow

Step I

• Completely separate the cats in two divided environments within your house. Perhaps one cat could have the upstairs (environment A) and the other could have the downstairs (environment B). A closed solid door should separate the two areas so the cats cannot see each other. Water and litter boxes should be accessible to all cats at all times. Make sure each cat is aware of the other’s presence on the other side of the closed door, but confuse their tendency for territoriality by switching environments on a daily basis. In other words, the cat that was relegated to environment A should be put in environment B, and vice versa.
• As an alternative strategy, based on the floor plan of your household, you may decide to isolate the aggressive cat in a specific room and allow the other cat to have free range of the house. Select two or more rooms with doors that you can close securely. Relocate the aggressive cat between the rooms on alternate days, leaving the door to the currently unused room open. The cat(s) with the run of the house will investigate the unused room and smell the scent of their feline housemate. Likewise, when the cat in custody returns to one of these rooms on the following day, he will smell his estranged companion’s scent. The daily exchange of scents maintains cat-to-cat familiarity in a non-threatening environment and prevents either cat from becoming territorially protective toward a particular environment.

Step II

Now begins the process of desensitization and counter-conditioning. If you are accustomed to feeding your cats “free-choice,” you will have to abandon this practice for more controlled feeding practices. One approach is that during the retraining period, all cats should be “meal fed” in the morning and at night so they will be hungry enough to want to participate in across-the-door socialization at mealtimes. The one thing the cats shouldn’t be able to do is eat wherever and whenever they want.

• Feed the cats simultaneously on either side of a closed door so they can hear and smell each other while they are eating. The food should be highly palatable. You may also choose to feed small bits of tuna, chicken, or other delectable treats.
• When the cats are able to eat next to each other on opposite sides of a closed door, the door should be cracked open one to two inches and secured with a doorstop or hook and eye. Once the cats are happy getting occasional glimpses of each other through the crack, the opening should be widened to a four to six inches. A newspaper-covered screen with a four-inch wide strip torn off will provide an appropriate physical barrier to prevent actual physical contact between the cats. The opening can gradually be enlarged to afford the cats increased visual access until eventually the whole screen is free of newspaper. The cats should always have enough time to get used to each other at each stage of exposure before proceeding to the next step.

Step III

• Once the cats are able to eat near each other across the screen, the next step is to reintroduce them to each other for a short while in the same room. At first they should be restrained on harnesses and supervised closely, one person for each cat, or be confined in separate cat carriers. They should be positioned at opposite sides of the same room and be kept there for up to 15 minutes, as long as they remain relaxed. During this time, they can be fed a meal and/or given treats, attention, or toys, whatever they prefer, to make the experience an enjoyable one. Each day, assuming things remain peaceful, they should be brought a little closer to each other and the time that they are together can be extended. The goal is to have them eating side-by-side and ignoring each other.
• Once the cats are eating peacefully side-by-side on harnesses or in their carriers, the next step is to free the more passive cat from the harness or carrier. If all goes well, the more aggressive cat can be released during the next feeding while the more passive cat remains confined in its carrier.
• If no signs of trouble are seen when each cat is freed individually, the next step is to try releasing both cats at the same time for side by side feeding. Next they can be left together for progressively increasing periods of time. One feeding station and one litter box should be available for each cat and should be located in open areas so the cats can always see each other and therefore not be surprised by each others’ approach.
• Once the cats can be together peacefully for extended periods of time, the owner should make sure to praise them or give them food treats whenever they are seen together. If the more timid cat begins to avoid the other one or if the aggressor starts intimidating the other cat, and attempting to control its movements or access to resources, it’s time to return to an earlier phase of the reintroduction program.

Finale

The process described above is tedious and it may take several months to achieve acceptable results. However, no matter how frustrating it may be, do not rush the reintroduction process.

Be advised that the above techniques work well in some, but not all cases. Some cats will never be able to be left alone together but they may be perfectly happy living separately in the same household.