Exactly what drives cats to be aggressive towards each other or towards people? It is very important to assess the circumstances leading to this aggressive cat behavior so we can explain which the triggers are.
Never rule out a medical condition. Your cat may seem normal but he may be suffering from a number of diseases that cause aggressive behavior, especially those that cause pain for example, an abscess in the mouth or tooth, trauma, even arthritis. It is very important to consult with a vet if this aggressive behavior suddenly appeared.
Some cats are not well socialized. Socialization is an important cat behavior. It will be much easier to introduce a new cat to the household if your cat has been socialized since a very young age. Cats that have not been well socialized lack the necessary skills to interact with other felines, and when confronted with a new situation such as the arrival of another cat they will become defensive and aggressive. The best way to deal with this situation is to leave the cat alone until he calms down. Leave the new arrival in a separate room. Introduction should be done slowly.
Cats are territorial. At home each cat has his own space or territory. This becomes evident when you bring home a new kitten or cat. It also occurs when another housemate tries to take over a space “own” by the other cat. To avoid confrontation make sure each feline has its own space, toys, utensils, litter box, cat tree, etc.
Another form of aggressive behavior it is the “redirected” aggression. It happens when something disturbs one of the cats or there is a sudden change on his environment. For example, if a cat is disturbed by the presence of a stranger, person or animal he can’t get to, he will redirect his aggression towards whoever is closer to him. The redirected aggression inhibits the bites therefore the cat becomes very dangerous. This type of aggressive cat behavior is spontaneous; it is virtually an impulse the cat cannot control.
Sometimes even petting your kitty can provoke aggression. Experts in cat behavior believe that repetitive petting may arouse some cats to the point it gets unpleasant and even painful. Your cat then becomes irritable and aggressive. Signs that your cat is bothered by the petting are flattened ears, tense body, twitching tail, and growling,
Play aggression is normal between kittens and young cats and it is the most common aggressive behavior directed towards people. Some felines never learned to inhibit this rough play and may become overly aggressive when playing with their owners. Some elements that promote this cat behavior are letting your cat “attack” your hands or feet and leaving him alone for long periods of time. You can teach your cat to play with his toys instead of your hands or feet. Use compressed air or spray water to deter rough play.
Whole male or female cats tend to show more aggression than cats that have been fixed, so the first step to avoid having an aggressive feline is to spay or neuter all your cats.