Reasons for cats fighting:

1. Playing. Some cat fights are not really fighting, they may be playing games. It is usually more common in kittens or more active cats.

2. Vent your emotions. If a cat has just experienced something unpleasant, it may vent its anger on another cat.

3. Estrus. When cats are in estrus, two cats of the same sex will also fight for the cat of the opposite sex.

4. Defensive attack. When some cats are frightened or faced with danger, the bolder cats will choose to attack.

5. Occupy territory. Cats have a strong sense of territory and are never allowed to share their own toys, food, nests, water, litter boxes, etc. If other cats come to snatch it, they will have to fight to determine the outcome.

6. Indicate the level. There is a clear social hierarchy among cats. Therefore, cats will fight to prove their status.