How to Solve Aggression Between Household Cats

Aggressive house cats
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Are your cats having trouble getting along? It's possible that sometimes good feline buddies in the past can change their minds about each other. One minute, two cats are engaged in mutual grooming, and the next, they're locked in a tooth-and-claw battle.

Aggression can be scary to witness and downright dangerous for your cats. You can restore calm to your home by learning how to identify what type of aggression your cats are displaying and employing techniques to stop it.

Illustrations of the different ways to break up fighting cats
Illustration: Kelly Leigh Miller. © The Spruce, 2018 

Why Do Household Cats Get Aggressive?

Aggression between cohabitating cats can come in several forms with different causes. It may be a playful exchange, sexual tension, a territory dispute, displaced anger, or just a simple female catfight. If you can determine the type or cause of aggression, you have a better chance of solving the issue with an appropriate technique.

Play Aggression

Also called "play fighting," play aggression starts at an early age with littermates or with nonrelated kittens sharing a household. Cats have a natural instinct for survival, whether in the wild or in a cushy home and early on are taught predator-prey behavior by their mothers. One kitten may "stalk" the other, then pounce on its unsuspecting prey, and the fun is on. Kittens often trade off roles with the victim chasing its former predator. The "chase me" game is often a favorite in multi-cat homes among cats of all ages. 

Play aggression is also a natural (and normal) step toward establishing a permanent hierarchy or "pecking order" among feline housemates and is usually harmless fun. Intervention is only necessary if it appears that a cat is being hurt, if the fighting continues for too long, or if it turns into sexual aggression. To protect your cats from scratching injuries, trim their claws regularly, which is generally a good practice for regular kitty maintenance.

Sexual Aggression

Even neutered cats occasionally partake in mounting and humping behaviors, especially if they were neutered after sexual maturity. In some cases, cats' sexual aggression toward each other borders on what's called dominance or territorial aggression. This type of aggression is easy to identify. The aggressor bites the nape of the neck of the victim cat and attempts to mount it using the thrusting hip movements as in mating.

Territorial Aggression

Territorial or dominance aggression can sometimes arise suddenly between two relatively evenly matched cats. It may take place between males, females, or one of each sex. Territorial aggression is the form of fighting that's often accompanied by marking with urine. If you notice urine spraying during a fight, then it's clearly a territorial dispute.

The aggressor cat may not necessarily be an older cat or the one that's been in the household the longest. The aggressor usually prefaces its attack with posturings such as a raised back, laid-back ears, and growling and hissing and is then likely to try to leap on its victim and attempt to bite the back of its neck. In many cases, the "victim" cat may back down, turn, and walk slowly away. This is a sign that a social hierarchy power struggle has begun. Most kitty housemates eventually resolve their disputes. One will reign as the alpha cat, and the other will be satisfied with its lesser role in the hierarchy.

Displaced Aggression

Displaced aggression has to do with a trigger that bothers one cat, who then takes its aggression out on another cat (or human). This is also known as redirected aggression. Redirected aggression is usually a temporary situation unless you allow it to escalate. If the two cats get along, for the most part, you can reset the relationship by keeping the cats separated for a day or two until they both forget the incident.

Female Cat Fights

Female cats have their own playbook and are prone to fighting. They're often very territorial and resent other females intruding into their space. Female-on-female aggression most often takes on the characteristics of territorial aggression, and you handle it much the same way.

Another form of aggression unique to female cats is that of aggression toward an adolescent male kitten whom they may have "adopted" and cared for when it was younger. One day (much to the young cat's surprise and dismay), his previously loving surrogate mother suddenly turns on him, growling, hissing, and attacking. This form of aggression may take place whether or not the female is spayed and or whether or not she has borne kittens herself. It may be described as "get out of the nest" aggression.

This kind of behavior is also observed in big cats in the wild. It's not unusual for a pride of lions to chase off the adolescent males, forcing them to move on elsewhere to establish their own pride.

How to Stop Cat Aggression

Just as there are many forms of cat-to-cat aggression, there are several ways to settle aggressive disputes. Don't attempt to physically separate two fighting cats. In the heat of the fight, they won't recognize you and could injure you severely. Provide regular physical and mental exercise with interactive toys. If you do this consistently, your cats are likely to enjoy peaceful companionship for years.

Distraction

Overly zealous play aggression, sexual aggression, and most territorial and dominance aggression can be dealt with effectively by distracting the cats and redirecting their attention. You can also throw a pillow at the fighting cats, spray them with water, or try to distract them with food. If that doesn't work, try some other distractions:

  • Loud sounds: Clap your hands, then say "No!" or "Time Out!" in a loud voice. Or blow a whistle or sound an air horn or another loud instrument.
  • Give the cat a toy: Provide the aggressor cat with a large stuffed toy such as a teddy bear. Keep it aside as its own personal "surrogate victim," and throw it to the cat to redirect its attention away from the actual feline victim. You can also bring out an interactive toy, such as Da Bird, to redirect all the kitty's pent-up aggressive energy.

Scruff Them

Never physically intervene between two cats locked in combat. If you find a moment (during pauses between attacks with less violent fighting or during sexual aggression) try scruffing the cats. This is a close approximation of the action a mother cat would take with an unruly kitten. Scruffing is done by grasping the loose skin at the scruff of the neck of the aggressor cat, then gently, but firmly, pushing him down toward the floor. Sexual aggression between cats can also be discouraged by scruffing.

You can accompany scruffing with loud hissing to reinforce a cat's memory of its mother from kittenhood. The aggressor cat will likely relax into a subservient posture and may even roll over slightly. You may also be able to stop sexual aggression by redirecting your cat to another activity such as playing or eating.

Usually, the victim cat flees the scene as soon as the other cat is distracted. Once you're sure the aggressor has calmed down, release the cat and talk to it quietly. Give the cat a few gentle strokes, much like how a mother cat would lick and groom a kitten she had just disciplined.

Physically Separate Them

Another form of physical intervention is segregation. This may be necessary when several fights have occurred between two cats or in the case of redirected aggression. Assign a "time out" room for the aggressor cat, and allow the victim to have the rest of the house. This type of separation may last for only an hour or two or as long as a day or two. Some cats might even need several months, but most eventually develop their own peace accord.

Remove Stressors

When possible, remove the stressor. If you notice that there's something bothering one cat, and this leads it to launch an attack at another nonantagonistic cat just sitting idly by, manage the scene. For example, if the cat becomes agitated by seeing a neighborhood cat walk by outside the window, you can draw the blinds.

Professional Treatment

There are some cases in which you may be faced with the dilemma of two cats that will never get along and may need to be permanently separated. But, before resorting to that, seek the help of a cat behaviorist or your veterinarian to come up with more advanced solutions.

If all else fails, you may have to resort to medication for the aggressor cat or the victim. Be sure to talk to your veterinarian or a specialist in cat behavioral problems about your concerns. It's important to rule out a medical problem with one or both cats before moving on to treatments. There are a few medical therapies to explore:

  • Prescription medications: Fluoxetine, alprazolam, trazodone, and other anti-depressant and anti-anxiety medications may be recommended for one or both cats. Some are prescribed for the aggressor cat to calm its aggressive tendencies.
  • Nutraceuticals/supplements: Calming agents in the form of treats may be helpful to minimize stress and anxiety in one or both cats. A common type recommended by many vets is Solliquin, which helps balance behavior and encourages relaxation.
  • Holistic remedies and other natural remedies for stress, like essential oils or herbal treatments, are available to counter the stress or fear that accompanies aggression by another cat.
If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.