There are numerous types of feline aggression:

• Maternal
• Pain Induced
• Petting Induced
• Play
• Redirected
• Territorial
• Fear Induced 
• Idiopathic

This article shall serve to provide information on each type of aggression and how some might be avoided and to some degree, handled.

Maternal 

Maternal aggression, as you might expect, originates from a queen if provoked after she has given birth to kittens. Generally she is acting to protect her kittens. Mother cats can be quite ferocious and will not hesitate to scratch and/or bite if pushed beyond their limits. Unless you have an excellent relationship with the queen, it is best to leave her and the kittens alone.

Pain Induced 

Pain Induced aggression results from cats that are suffering from pain, usually related to a medical condition, but not always. These cats try to give signals that they do not want to be touched or handled, but the signals can be quite subtle and easily missed by those who are not familiar with feline body language. Pain can be caused by a very visible injury such as a bite wound or broken bone. However, like people, cats can suffer from unseen, many times chronic, maladies such as feline stomatitis and arthritis. Cats with hyperthyroidism sometimes exhibit aggression, although it is not related to pain. If a person does not pick up on the signals that a cat doesn't want to be petted/touched, the cat's behavior can escalate to aggression involving spitting, scratching, biting, even attack. If your cat has always been gentle and kind and suddenly is aggressive, it's best to get kitty to a veterinarian for examination and treatment.

Petting Induced

Petting Induced aggression stems from petting a cat in an area the kitty doesn't like, possibly from being startled if petted while asleep or receiving too much petting in one area. Many cats enjoy petting to their heads and cheeks, but cannot tolerate petting down their backs, on their feet and certainly not their abdomens. Cats will bite if they continue to receive petting in such uncomfortable areas. If a cat is sleeping, even gentle petting could startle them and cause an attack to your hand. Wait till kitty is fully awake to offer attention. Like people, over stimulation by petting or rubbing can be very uncomfortable, even painful. While petting, be mindful that the cat is exhibiting relaxed postures and is truly enjoying the attention.

Play 

Play aggression arises in two ways. One occurs when play has become rough; the second is more of a predator-play aggression. In the first instance, We find that the cat is playing with a human or another animal. It starts out fun and mild, but the cat gets over stimulated, becomes very rough, possibly escalating to attack on the other party. While interactive play with cats is definitely encouraged, one very important rule for people is..DO NOT PLAY WITH A CAT USING YOUR HANDS!!! This is so easy to do with kittens because they can cause so little harm. However, the kitten grows to adulthood and won't understand why it's no longer ok to play that way. JUST DON'T DO IT!! When playing with kittens and cats, use toys such a feathers, etc., on wands or "fishing pole" toys. No one gets hurt if kitty becomes over stimulated. Secondly is predator-prey aggression.  This form of aggression results when cats are not receiving enough play time. Play is so very important, particularly hunting games. It's great "training" for cats, but also is a fantastic way to let out the physical energy they need to release. Cats are hunters and they will find prey where they can in order to play this game. Unfortunately, sometimes this includes ambushing and jumping on other pets or even people. These "ankle attackers" must have play incorporated into their routine to keep them happy and fulfilled.

Redirected

Redirected aggression generally occurs between pets, usually between two cats, but can also occur with to people. The usual scenario is where two animals are viewing something of interest, but something that could be threatening. They become so involved in the object they are watching, that if they look away and the other party is directly in their path or the other party moves, they perceive a threat to themselves and attack the other party. It doesn't seem fair, but it's a natural instinct for many cats to protect themselves this way. Basically the cat is deeply engaged, becomes startled and takes that energy and emotion out on another party. These cases can last only moments, but sometimes the ill will or fear of the other party that arises can last and will need to be resolved through behavior modification. In some cases, medication is required to calm the cat(s) for behavior modification to be effective.

Territorial 

Territorial aggression arises when a cat's territory has been violated. Usually the perpetrator is another cat, but can be other animals or people. The typical case scenario is where a male cat has entered another male cat's territory and a fight ensues. However, this same type of aggression occurs when a family brings another pet, sometimes even another person, into a household. The previous cat has claimed the home as its own territory and is not willing to share. If the issue is outside, there is a chance that fencing, even cat fencing, will keep intruders out. If this occurs in the home when a new member arrives, it will be necessary to provide slow introductions and add resources for the new member.

Fear Induced

Fear Induced aggression, as its name implies, occurs when a cat is afraid. Veterinarians, vet techs, shelter staff, etc., can all relate stories of fear aggression in their lines of work. It can also happen in the home, particularly with strangers. Cats would prefer the "flight" response as opposed to fighting and will generally only attack if they have been pushed to the point they feel they have no escape alternative and must protect themselves. It doesn't matter that we might actually be trying to help a cat. If the cat perceives an inescapable threat, aggression in the form of spitting, scratching, grabbing hold and biting could all result. It's best to move slowly and speak reassuringly in a low voice to try and avoid pushing a cat to this level of excitement. Giving the cat some space and time to calm down will also help.

Idiopathic 

Idiopathic aggression, as the term indicates, seems to have no clear genesis. The cat is aggressive, lashing out and fighting for no apparent reason. There is always a reason; although finding it might be a challenge. There could possibly be brain disease or a neurological reason. If no plausible reason can be determined for the aggression, it's best to have a veterinarian examine the cat. This may require blood work and x-rays for a proper diagnosis.