Feline Aggression

Preventing aggression towards humans
When we talk of aggression we never associate it with our domestic cats, however, feline aggression is a serious problem that can result in injury to other animals and people. In addition, zoonotic diseases can be spread from cats to people through aggressive acts. Aggression is commonly seen in the form of play behaviour in kittens.

Aggression caused by lack of socialization
There is increased risk of aggression towards humans if cats did not have human contact during the critical periods. Cats that are not handled until 14 weeks of age are more fearful and aggressive toward people, regardless of the circumstances. Such cats do not voluntarily approach humans and are aggressive if they cannot escape. In contrast, cats handled for as little as 5 minutes per day from the day they are born until they are 7 weeks of age are quicker to approach and solicit people for interaction and gentle play, quicker to approach inanimate objects, and quicker to play with toys.
Socializing cats to a variety of people, including men, women, and children, may prevent some forms of human-directed aggression. If possible, expose kittens to humans before the kitten is 7 weeks old. Handling by people should be frequent, pleasant, and gentle. Include handling that mimics basic health care procedures, including grooming, clipping claws, checking ears, and brushing teeth. If an adult cat has not been exposed to such handling as a kitten, start with very brief sessions. Reward the cat for cooperation.

Play aggression
Kittens often play roughly with other cats or kittens. The queen and other kittens teach the kitten to temper their play. Cats that as kittens never learn to moderate their responses may play too aggressively with people. Use interactive toys (eg, a fishing pole-type toy with fabric or feathers at the
end of it) instead of letting the kitten play directly with their hands or feet. Adult supervision is needed when allowing children to play with and handle kittens and cats; this supervision will prevent injury to all involved and make the kittens/cats have a happy association with the child.

Aggression associated with petting
Some cats become less tolerant of petting as they become socially mature. Cats with this condition actually solicit attention from people, but tend to bite if petted for more than a few seconds. Those cats may have a form of impulse control aggression. Such aggression can be avoided if you learn to give those cats attention in other ways and pet the cat for very short periods only

Redirected aggression 
If a cat is highly stressed by an outdoor cat or another animal, the cat may redirect that aggression toward anyone nearby. This victim could be another household cat with which there had been no previous problems or an unsuspecting family member. Never attempt to handle a cat in this state, because serious injury may result. If one cat is attacking another, a noise can distract or startle the attacker and interrupt the event. Another way to separate them is by squirting water directly at the cats. However, some cats will be rendered more aggressive by these stimuli, so caution is urged in using any disruptive stimulus. If cats must be handled while in this reactive state, throwing a blanket over them can allow safe handling to occur.

Pain-associated aggression
Pain can cause aggression. A cat may attack an individual who causes pain (eg, a person combing over arthritic hips or brushing a painful tooth) or have lower tolerance because of pre-existing
pain. Because painful conditions such as arthritis, dental disease, intervertebral disk disease, meningioma, or injury often induce aggression, clients are strongly encouraged to immediately take a cat that becomes aggressive to a veterinarian for them to check for an underlying cause.

Predatory behaviour
Cats are hunters and will go after prey even if not hungry. The best way to prevent predatory behaviour is to raise kittens with potential prey animals (eg, pocket pets or birds). Even if cats are not
aggressive, you should ALWAYS supervise them whenever they have access to potential prey. To prevent predation of wildlife you should keep cats indoors, confine them to outdoor cat enclosures, or leash-walk them. Placing bells on the collars of free roaming cats does not always prevent predation because cats can learn to stalk without the bell ringing.

Inter-cat aggression
This is one of the most common aggressive problems that people are most concerned about, aggression between cats within the same household. However, unless there is evidence of wounds, they often miss subtle aggression. Aggressors can control access to food, litter boxes, resting and perching spots, and attention, and the victim usually becomes withdrawn. Both the aggressor and the victim may have undesirable elimination and other behaviours.
Inter-cat aggression is most likely to occur when a new cat is introduced to a household, a resident cat has been absent and returns to the home (eg, after a veterinary visit), and when there is competition for resources (eg, litter boxes, food, and resting areas). Multiple resources should be easily accessible.
To prevent inter-cat aggression, gradual introductions should be made if adopting another cat
If aggression occurs after the return to the household of a resident cat, the cats should also be reintroduced gradually. You can purchase pheromone products like Feliway that can help reduce aggression when unfamiliar cats are introduced to existing residents. Although these products may be helpful as part of a complete behaviour treatment plan, they are not a substitute for social interaction and exposure.