There are many different reasons why cats can be aggressive towards their owner or other people. To be able to successfully treat the problem, it’s essential to work out what the underlying cause, or trigger, is. To do this, we highly recommend that you consult with a qualified veterinary behaviourist (your local vet can refer you). They will ask you lots of questions and may also visit you in your house so they can observe the cat in its own environment and its interactions with you and any other members of the household.

Medical conditions can cause aggression so it is important to rule out any underlying medical causes prior to addressing behavioural causes for aggression. Neurological disease, liver disease, pain-inducing disease e.g. arthritis and hormone imbalances can cause aggression.

This article provides some basic advice about seven common types of aggression in cats and how to deal with them:

1. Patting aggression
2. Fear aggression
3. Redirected aggression
4. Pain-induced aggression
5. Play aggression
6. Noise-induced aggression
7. Sexual aggression

1. Patting aggression

In patting-induced aggression, the cat will not approach the victim to attack, and does not generally actively avoid people, as the ‘fear aggressive’ cat does. Instead, it becomes aggressive at some point after it has been patted for a while. Typically, aggression occurs sooner and is more intense if the person has initiated the patting, e.g. by picking the cat up and putting them in their lap, than if the cat initiated the petting. However, petting-induced aggression can occur in both situations.

Some cats do not tolerate being patted for a long period. In these cases the cat tends to be very content while being patted initially, then suddenly it attacks the person, jumps down, runs a short distance, sits, grooms, with pupils dilated.

Prevention

• Don’t pat the cat for a prolonged period
• Wait for the cat to initiate patting – and then keep it short
• Look out for any signals that the cat sends when they do not wish to be patted anymore and use these as your cue to stop patting
• Desensitise the cat by patting for at first very short and then increasingly longer times, while rewarding the cat with food treats for tolerating the patting.

2. Fear aggression

Cats usually display fear aggression when they feel threatened, especially when cornered. Initially the cat tends to show defensive body language and will attempt to avoid the person they are afraid of, but when cornered they may become quite aggressive. Ears will generally be turned back, and the tail and body lowered, but the teeth will be displayed and hissing or growling may occur. Cats with fear aggression generally do not approach the victim. This problem can occur at any age.

Causes of fear aggression include a lack of socialisation, genetic predisposition and a cat’s general personality. Inappropriate human-cat interactions, such as a history of punishment, can also influence the development of fear aggression.

Prevention

• Avoid potential triggering situations
• Systematically desensitise the cat by gradual exposure to the fearful stimulus
• Give the cat a food treat while it is calm during the trigger situation. Rewarding with a food treat whilst calm reinforces relaxation during exposure to the fearful event. This is known as ‘counter-conditioning’ (associating a fear-evoking situation with a pleasant experience)
• Teach the cat to perform an alternative behaviour in situations in which fear was shown. This is known as ‘response substitution’
• Sometimes medication can be used in combination with behavioural modification (your vet will advise)
• Synthetic pheromones can also have a calming effect (e.g. Feliway® spray/diffuser – available at vet clinics).

3. Redirected aggression

Redirected aggression occurs when a human attempts to handle a cat that is aroused by something unrelated to the person, e.g. the dog has been chasing the cat or the cat is fighting with another cat. Typically, redirected aggression starts when a cat sees another cat outside or smells another cat and becomes aggressive (territorial aggression), but can’t directly interact with the outside cat. She will then redirect the aggression to another cat in the household or a person.

If the aggression is directed to another cat in the household, this can result in inter-cat aggression whenever the cats meet again, and will not resolve without specific treatment. In either case (when directed towards cats or towards humans), redirected aggression is likely to occur repeatedly unless the trigger can be removed.

Prevention

Take steps to avoid the trigger situation from occurring, e.g. by preventing access to window sills, covering windows or keeping stray cats away

Avoid handling the cat if they appear aroused by something

Alternatively, systematically desensitise the cat by gradual exposure to the fearful stimulus, or

Give the cat a food treat while they are calm during the trigger situation. Rewarding with a food treat whilst calm reinforces relaxation during exposure to the fearful event

Medication may also be used in combination with behavioural modification (your vet will advise).

4. Pain-induced aggression

This form of aggression may be shown in response to a painful procedure, or the anticipation of a painful procedure. Chronic pain may also increase irritability and make the cat more aggressive (e.g. arthritis).

Prevention

• Avoidance of the trigger
• Systematic and gradual desensitisation to situations that were previously associated with pain
• Give cat a food treat while it tolerates/is relaxed during the trigger situation
• Provision of pain relief for conditions resulting in acute or chronic pain (your vet will be able to assist).

5. Play aggression

One of the most common types of aggression is play aggression. Vigorous play in cats is part of normal cat behaviour. These cats are usually young, energetic cats living as single cats in a household and sometimes have a history of being taken early from their mother and siblings. Often, owners contribute to the problem by playing roughly with the cat when it is a little kitten, rewarding it for biting and clawing by continuing the play.

Play aggression typically involves the cat approaching the target (stalking) and then leaping onto the target. There is usually no warning growl or hiss. The attacker may hide in wait behind a barrier, intensely focused, and with their tail twitching. The cat does not exhibit dominance posturing toward the victim, and does not retreat from or avoid the victim with characteristic signs of fear. In fact, the cat often hides behind some furniture and waits until a person walks by, and then dashes out and attacks the person’s ankles. Hands dangling over the armrest of a chair are also favourite targets.

Prevention

• Avoid trigger situations where possible
• Do not encourage aggressive play: this involves ignoring unwanted behaviour (not reinforcing it with your attention). If your cat tries to play aggressively move away from the situation, preferably into another room, shut the door and do not react. No reaction means that your cat receives no attention for the unwanted behaviour (and thus they are less likely to continue that behaviour if they learn that they won’t get any attention when they do it)
• Positive reinforcement training also involves rewarding ‘good’ behaviour. So when the cat is playing with her cat toy or when he is calm and relaxed, you can reward him with a food treat
• Confrontational reactions such as physical punishment, or reacting to the aggression with fast movements or high-pitched vocalizations, may simply reinforce the aggression (via negative reinforcement). This is because any reaction by the owner (even negative) is still attention and some cats would prefer to have negative attention than to have no attention at all
• Protect yourself – put bells on your cat, so that you can hear where she is
• Redirect the behaviour – once you have interrupted an attack by ignoring and moving away, toss a toy for the cat to initiate appropriate play. You can then reward her for ‘good’ behaviour. Learn how to predict an attack and redirect the behaviour before it occurs
• Provide interesting toys, and rotate their use  (avoid string toys as these can become intestinal obstructions if swallowed)
• Interact in appropriate play. To teach your cat to interact appropriately with you, and to satisfy their need for social contact, have daily play periods. In these play periods, interact with your cat using toys. The idea is to allow for playful interaction and expression of predatory behaviour but without giving the cat the possibility to bite/scratch you directly
• Teach bite and claw-inhibition using positive reinforcement training. Do this initially when the cat is calm, NOT when it is motivated to play. Gently pat or play with the cat. Don’t get her excited, because then rough play is likely to escalate and she won’t learn that this is undesirable.
• As long as the cat remains gentle, let her nibble and hold your hand. As soon as she puts any pressure on your skin, immediately stop playing and ignore her for some time. This will teach your cat to play very gently, just as one kitten would learn from another (positive reinforcement training). As time goes by, you reduce the amount of pressure that you tolerate more and more. You can teach even an adult cat not to grab you with their mouth, and to never use their claws when interacting with you.

6. Noise-induced aggression

Cats may respond to certain sound frequencies with aggression. Examples include a baby crying, another cat crying, high-frequency whistling or squeaking sounds. A possible explanation might be the elicitation of predatory behaviour by high-frequency sounds.

Prevention

• Avoid trigger sound frequencies (where possible)
• Where appropriate you can attempt desensitisation and counter-conditioning. Desensitisation to noise means playing the ‘trigger’ sound at a very low volume and if the cat remains calm/relaxed she can then be rewarded with a food treat (counter-conditioning). The volume is then very slowly increased over time and the cat continues to be rewarded as long as they remain calm and relaxed during the sound.

7. Sexual aggression

Only male cats exhibit sexual aggression. The cat will mount a person’s arm or ankle, grab the skin with its teeth, and initiate pelvic thrusting. Attempts to dislodge the cat at this point will result in increased aggression. While a female cat’s thick scruff generally protects her from actual harm due to the male's nape-bite (back of neck), human skin is not so well protected and can result in injury. This may occur as a result of incorrect sexual imprinting.

Prevention

• Learn to recognise the triggers for an aggressive sexual mount and then avoid the situation (e.g. leave the room).
• When this behaviour starts, distract the cat with a toy instead or food (food treats should not be given if the cat is already showing aggression as this may negatively reinforce the behaviour).