As an owner of multiple cats (four, to say), there have been several occasions wherein one cat acts aggressively towards the others. Sometimes, she lashes out for no particular reason. This may be a common problem for cat owners who own several cats at once.
Let’s take a look at the aggression between cats, as Paws.org gives us more details on why this occurs.
If you think dogs are territorial, cats will surprise you. Cats are much more territorial than dogs. Thus, territorial aggression occurs when a cat feels that his territory has been invaded by an intruder. His territory depends on where he spends most of his time. He may view your whole neighborhood as his territory.
You’ll know if your cat has territorial aggression if he chases and ambushes the “intruder”, as well as hisses and swats when contact occurs. This is common when a new cat is brought into the household, or when a young kitten reaches maturity, or when a cat encounters neighborhood cats outside. It is not uncommon for a cat to be territorially aggressive towards one cat in a family, and friendly and tolerant to another.
This usually happens between adult male cats when they are fighting over a female, or when males want to achieve a relatively high position in the cats’ loosely organized social dominance hierarchy. Adult male cats normally tend to threaten, and sometimes fight with, other males.
This type of aggression involves much-ritualized body posturing, stalking, staring, yowling, and howling. Attacks are usually avoided if one cat backs down and walks away. If an attack occurs, the attacker will usually jump forward, directing a bite to the nape of the neck, while the opponent falls to the ground on his back and attempts to bite and scratch the attacker’s belly with his hind legs. This may be a scary sight, but cats don’t usually severely injure one another this way. However, you should always check for puncture wounds that are prone to infection. Intact males are much more likely to fight in this way than neutered males.
Read the full article here for more details on aggression between cats.