Aggression toward another cat when disturbed while sleeping can be a normal startle or even survival response. However, always take any aggressive episodes seriously. Being surprised or disturbed by a familiar or unfamiliar cat can lead to aggression and serious fights. Some fights can lead to serious injury to either cat. If you notice any aggressive or stress signs in your cat, address it immediately.
Pay attention to your cat's body language. If you don't know how your cat will respond when disturbed while resting or sleeping, pay close attention to how easily your cat startles. Aggressive behavior when startled or surprised while resting can be seen in cats of any breed, size, age, or gender. The most common reason for aggression is fear. Defense, territoriality or status may also a consideration and so is pain or discomfort. A fearful cat may exhibit dilated pupils, ears turning back, or a twitching tail. In this situation, your cat may growl, hiss or swat at the other cat. Your cat may appear nervous, frightened and startle easily when awake and try to run and hide in the presence of the other cat.
Even mild forms of aggression, when not properly addressed, can evolve into serious aggression or fear and anxiety. Assess and tackle any change in your cats' interactions and behavior right away. Work with a professional who can look at the context in which it happens. Never use punishment as a training technique. It will not work and will only hurt your relationship with your cats.
Always give each cat a safe place to rest. Safely confine your cats to their own separate areas. Make multiple elevated areas available for your cats, so each cat can rest safely in the presence of the other. If you must separate your two cats to prevent serious fighting, take time to re-introduce them. Some cat-to-cat introductions go very smoothly. Others may take weeks or months before your cats learn to co-exist with each other. The best thing to do is to go as slowly as necessary-don't rush the introduction if you are working towards a positive long-term relationship. Being patient will pay off!
This document created by the San Francisco SPCA with a grant from Maddie's Fund®.