Aggression toward another cat when outdoors can be a normal survival behavior or it can be a symptom of an underlying problem. Always take it seriously. Aggression towards another cat when outdoors can lead to serious fights and possibly injuries to either cat. It can also lead to disease transmission and should be avoided. Other forms of aggression might be more subtle and you may not immediately notice them. Nonetheless, it may result in stress signs, such as not eating, not using the litter box appropriately, hiding or over grooming. If you notice these signs in your cat, don’t let your cat go outside unless they are protected and safe from other cats.
Even the presence of another cat can evolve into serious aggression towards the cat, other animals or even humans, if not properly addressed. Redirected aggression can occur and is very dangerous to deal with. Assess and tackle any change in your cats’ behavior when in the presence of another cat 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.
Pay attention to your cat’s body language. Aggressive behavior can occur when a cat is being approached by another cat of any breed, size, age, or gender. It can stem from many different types of stressors. The most common include fear, defense, territorial, redirected, status, play, pain, and 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 cats. Your cat may appear nervous, frightened and startle easily, trying to run and hide. A more offensive aggressive cat may have their ears back, constricted pupils, and the tail may be up or down with fur standing on end.
It may be safer to keep your cat indoors.