Aggression Between Family Cats

If the battles between your feline family members are anything like the struggle between Cain and Abel, there are a few things you can do to prevent the "sibling rivalry" from reaching biblical proportions. Of course, it's almost impossible to guess how well any particular pair or group of cats will ultimately tolerate each other; some unusually territorial cats may never adjust to sharing their house, and may do best in a one-cat family. But many aggression problems between cats can be successfully resolved, even if the two don't end up best friends when all is said and done. You'll need to commit time and effort to solve aggression problems between cats, and don't give up without consulting the appropriate experts.

Common Types of Aggressive Behaviors between Cats:

Territorial Aggression: Territorial aggression occurs when a cat feels that his territory has been invaded by an intruder. Cats are very territorial—much more so than dogs—and female cats can be just as territorial as males. The behavior patterns in this type of aggression include chasing and ambushing the intruder, as well as hissing and swatting when contact occurs. Territorial problems often occur when a new cat is brought into a household, when a young kitten reaches maturity, or when a cat sees or encounters neighborhood cats outside. It's not uncommon for a cat to be territorially aggressive toward one cat in a family yet friendly and tolerant to another.

Inter-male Aggression: Adult male cats normally tend to threaten, and sometimes fight with, other males. These behaviors can occur as sexual challenges over a female, or to achieve a relatively high position in the cats' loosely organized social hierarchy. This type of aggression involves much ritualized body posturing, stalking, staring, yowling, and howling. Attacks are usually avoided if one cat "backs down" and walks away. If an attack occurs, the attacker will usually jump forward, directing a bite to the nape of the neck, while the opponent falls to the ground on his back and attempts to bite and scratch the attacker's belly with his hind legs. The cats may roll around biting and screaming, suddenly stop, resume posturing, fight again, or walk away. Cats don't often injure one another this way, but you should always check for puncture wounds, which are prone to infection. Neutered males are much less likely to fight in this way—yet another great argument for having your animal sterilized.

Defensive Aggression: Defensive aggression occurs when a cat is attempting to protect himself from an attack he believes he cannot escape. This can occur in response to punishment or the threat of punishment from a person, an attack or attempted attack from another cat, or any incident that makes the animal feel threatened or afraid. Defensive postures include crouching with the legs pulled in under the body, laying the ears back, tucking the tail, and rolling slightly to the side. These responses are not the same as the submissive postures dogs show because they're not intended to "turn off" an attack from another cat. Continuing to approach a cat in this posture is likely to precipitate an attack.

Redirected Aggression: This type of aggression is directed toward another animal, or even a person, who didn't initially provoke the behavior. For example, a household cat sitting in the window may see an outdoor cat walk across the front yard. Because he can't attack the outdoor cat, he may instead turn and attack the family cat sitting next to him in the window.

What You Can Do

• If your cat's behavior changes suddenly, your first step should always be to contact your veterinarian for a thorough health examination. Cats often hide symptoms of illness until they're seriously ill, and any change in behavior may be an early indication of a medical problem.

• Spay or neuter any intact pets in your home. The behavior of one intact animal can affect all of your pets.

• Start the slow introduction process over from the beginning. You may want to talk to an animal behavior specialist for help implementing these techniques.

• In extreme cases, consult with your veterinarian about medicating your cats while you're working on a behavior-modification program. Your veterinarian is the only person who is licensed and qualified to prescribe medication for your cat, so don't attempt to give your cat any over-the-counter or prescription medication without some guidance. Animals don't respond to drugs the same way people do, and a medication that may be safe for a human could be fatal to an animal. Also keep in mind that medication, by itself, isn't a permanent solution, and should only be used in conjunction with behavior modification.

What NOT to Do

• If your cats are fighting, don't allow the fights to continue. Because cats are so territorial, and because they don't establish firm dominance hierarchies, they won't be able to "work things out" as dogs sometimes do. The more often cats fight, the worse the problem is likely to become. To stop a fight in progress, make a loud noise (like blowing a whistle), squirt the cats with water, or throw something soft at them. Don't try to pull them apart.

• Prevent future fights. This may mean keeping the cats totally separated from each other while you're working on the problem, or at least preventing contact between them during situations likely to trigger a fight.

• Don't try to punish the cats involved. Punishment is likely to elicit further aggression and fearful responses, which will only make the problem worse. If you attempt to punish either combatant, you may even become a target for redirected aggression.

Because their social organization is somewhat flexible, some cats are relatively willing to share their house and territory with multiple cats. It's not uncommon for a cat to tolerate some cats, but not get along with others in the house. But the more cats who share the same territory, the more likely it is that some of your cats will begin fighting with each other.

When you introduce cats to each other, one of them may send "play" signals that can be misinterpreted by the other cat. If those signals are interpreted as aggression by one of the cats, then you should handle the situation as "aggression" and seek professional help right away.

There are many factors that determine how well cats will get along with one another, but even animal behavior experts don't fully understand them. What we do know is that cats who are well-socialized (those who had pleasant experiences with other cats during kittenhood) will likely be more sociable than those who haven't been around many other cats. On the other hand, "street cats," who are in the habit of fighting with other cats to defend their territory and food resources, may not do well in a multi-cat household.


© 2002 The Humane Society of the United States. Adapted from material originally developed by applied animal behaviorists at the Dumb Friends League, Denver, Co. All rights reserved.