If the behavior is directed to animals outside, then keeping the cat indoors is a solution. Predatory aggression may be part of play aggression in young cats. Pain-induced aggression is usually elicited by handling or contact that elicits pain or discomfort. Fear and anxiety further compound many of these cases. Once your cat learns that aggression is successful at removing the stimulus, aggression may recur when similar situations arise in the future, whether or not the pain is still present.
Treatment requires first that the medical or painful condition be resolved.
Next, identify the types of handling and situations that have led to aggression in the past. Once the cat learns that there is no further discomfort associated with the handling, and that there may be rewards, the problem should resolve. Maternal aggression is directed toward people or other animals that approach the queen with her kittens. With desensitization, counterconditioning, good control and highly motivating rewards, it may be possible to train your cat to accept handling of the kittens. Once the kittens are weaned, spaying should be considered to prevent recurrence.