Cat fight or inter-cat aggression is a common thing in aggressive cats as well as calm and nice kittens. When they start fighting, they begin yowling and hissing. You need to understand the behavior of cats before you judge why they are mocking. There might be numerous reasons of their clash but learning the signals you can minimize the chance of their wrangle occurring.
Mostly same gender of cats fight each other specially in mating season. That’s why neutering and spaying is the most recommended solution to reduce their conflict. It reduces aggression about 90%. Still this is not enough, you may face their fight still.Source: i.ytimg.com