Cats demonstrating aggression against their owners or other cats can be a force to be reckoned with. If the aggression is addressed and reversed early on, when the cat is still just a kitten, it's possible to eliminate the behavior altogether with a little patience. But not all aggressive cats can be rehabilitated. A lot is determined by what is causing the aggression, or even if it's true aggression to begin with.
It May Not Be Aggression
A cat who suddenly turns and bites your hand after you've been quietly petting him is not aggressive. The scenario goes something like this: you're lovingly petting your cat who is lying on your lap, quietly purring. Suddenly, and seemingly without warning, your cat turns and bites your hand. Your first reaction is shock, then maybe anger or bewilderment. Feline expert and best-selling author Pam Johnson-Bennett surmises that this behavior is due to your kitty simply having had enough. After her subtle warnings fail to get you to stop petting her, she bites out of frustration. Learn to understand and decipher subtle changes in your cat's demeanor, such as a slight lashing of the tail, termination of purring, twitching, growling or looking back at your hand.
If your cat is attacking people or other pets without warning or provocation, you may be rehabilitating either a feral cat or a long-time stray. Feral cats have never had a loving home -- they're wild animals, just like raccoons or opossums. Feral cats usually cannot be rehabilitated since they were never habituated to people in the first place.
A stray cat, on the other hand, once had a home and has some experience with people. He was lost or abandoned and may have reverted to a semi-feral state to survive. Eventually he was found and adopted, but if he was away from people for a long time, he may still be somewhat wild. He won't be very trusting and may react to perceived threats of danger. This cat may be rehabilitated, but it will take time and patience, and he may never truly become the sweet pussycat you hoped for. He may tolerate being around humans, but will remain aloof and cautious.
Aggression Toward Other Cats
Cats are predators and, as such, they learn to stalk and pounce on anything that moves when they are still very young. If your cat has ever been ambushed while using the litter box or hasn't come to a truce with another resident cat, there may be tension and even outright aggression between them. While these cats may never become best friends, they may learn to tolerate each other's presence. Never let them "work it out," as cats, unlike dogs, are not just trying to establish a hierarchy, they are truly trying to hurt each other, which can result in serious injuries. Keep them separated when you can't supervise, and break up any cat fights with a loud distraction or spray bottle. Time is the remedy for any hope of rehabilitation in such a case.
The techniques you use for managing aggression will depend upon what's causing it, but some tips for rehabilitating aggression cats are universal. For example, don't pet in an effort to calm him after he's bitten or attacked someone, as you're only reinforcing the bad behavior. If a cat is stalking or provoking a fight with another cat, redirect his attention with food, toys or catnip. Never hit your cat -- it will only cause him to act more aggressive. Phermones such as Feliway or herbal remedies such as Rescue Remedy may be helpful in calming down an aggressive cat. For a serious anxiety or aggression problem, seek advice from a certified cat behaviorist or consult a vet who may want to prescribe anti-anxiety medication.