It is not typical behavior of Maine Coon cats to be aggressive, and most breeders do not have this issue. If your cat is a rescue, the cat could have been previously abused or neglected or become stressed from the adoption process. However, it can be socialized. On the other hand, if your cat is suddenly being aggressive, it could be an underlying health issue, overstimulation, a perceived threat from other pets or territory, boredom, family tensions, or protective maternal instinct.