How to Solve Aggression Between Household Cats

Fighting between cats that live in the same household can be upsetting and frustrating. In many cases, it can be prevented and resolved with the help of a cat behavior professional and a veterinarian. Cat behavior is complex, and there are a variety of reasons aggression can occur.

Why Do Household Cats Get Aggressive?

Aggression is not a diagnosis; it is part of normal feline behavior and is strongly influenced by early social history, exposure to humans and other animals, gender, social context, handling, personality, and many other variables. Aggression between cohabiting cats can arise in several forms with different causes. Fear, anxiety, medical issues, improper introduction of a new cat, and lack of resources can all contribute to aggression between cats within a household.

Lack of Socialization

Socialization is the process of preparing a cat to enjoy interactions and feel comfortable with other animals, people, places, and activities. Ideally, socialization should begin during the "sensitive period," which is between 2 and 7 weeks of age for kittens.

Many cats do not receive adequate socialization, and as a result, problems are more likely to arise when one or more adult cats that have not been socialized with their own species are involved. Without appropriate experiences, these cats do not understand normal feline communication and etiquette and are likely to have intense and inappropriate responses to seeing another cat. They may run away and hide in fear, or they may attack in an attempt to drive the other cat away from their personal space.

During adequate socialization, the animal should develop appropriate social behavior toward their species and others with which they have been properly socialized. This will positively influence social behavior expressed later in life.

Introducing a New Cat

Properly introducing your new cat to your existing cats is essential, as introductions often lay the groundwork for their relationship. If your current cat has lived with other cats and was always friendly, it can be tempting to let your new cat into the same space right away. You may assume they will just work it out, but cats don't always get along initially, and a negative first meeting can set a poor foundation for their relationship.

Cat-to-cat introductions should be done slowly, keeping the needs of each cat in mind. It can be hard to resist the urge to let the cats meet immediately to start a wonderful friendship, but if you let your new cat loose in the home, several things can happen with poor consequences.

Your existing cat may feel their territory has been invaded if the newcomer is just let loose to explore. This could lead to your established cat feeling unsafe in their home, causing behavior changes or aggression toward the new cat. That helps neither of them!

From the new cat's perspective, they may be unsure of where they are. Every scent and sound is unfamiliar, and a possible threat lurks around every corner. If you have adopted your new cat, they have likely encountered a controlled number of sounds and smells. They may also be used to living in a small space, and while you want them to experience 'freedom,' rushing this process can leave them feeling overwhelmed and stressed.

Competition for Resources

In multi-cat households, it is not uncommon for one or more cats to block access to important resources, such as food, water, and litter boxes. It is crucial to provide multiple and separate key environmental resources such as litter boxes, water, food, hiding spaces, places to perch, resting/sleeping areas, play areas, scratching areas, and toys. Doing so helps decrease social tension and competition, reduces territorial behaviors, and provides choices that help prevent aggression among cats.

Cats generally prefer not to fight. They would rather flee or avoid each other, as fighting can lead to injury. However, if these options are unavailable, aggression becomes the last resort. In multi-cat households, the cats are often unrelated, yet they must share resources and have limited opportunities to hide or avoid potential conflict situations.

Medical Issues

If you notice your cat has sudden changes in behavior toward another cat in the home, it should be examined, and diagnostics should be performed to rule out underlying medical issues. Cats in pain can uncharacteristically exhibit aggression. A cat may begin to growl or hiss when other pets in the household approach them, displaying increased irritability. Medical conditions such as hyperthyroidism, dental disease, osteoarthritis, and cognitive dysfunction can also cause increased irritability and aggression between cats.

Lack of Predatory Outlets

Cats have natural behaviors and needs, and they must have opportunities to express them. It's important to provide your cat with predatory outlets, including a variety of toys, scheduled playtimes with cats separately once or twice daily, and puzzle food toys.

How to Treat Aggression Between Cats

Aggression encompasses a wide variety of complex behaviors that occur for different reasons under various circumstances. Early intervention is crucial�contact your veterinarian and a credentialed cat behavior professional as soon as you notice tension or aggression between cats.

• Identify any triggers that upset your cats, such as seeing outdoor cats or loud noises, and adjust the environment to minimize or remove these triggers.
• Create an enriched feline environment that allows for natural coping strategies. This includes multiple elevated single cat-sized resting perches throughout the environment, multiple litter boxes (the number of litter boxes should equal the number of cats plus one) located in different areas of the home, several feeding and watering stations, and multiple scratching posts or pads.
• Make sure cats have plenty of appropriate outlets for play and enrichment.
• Keep cats separated when not supervised or if aggression ranges from mild to severe, or keep them separated at all times to prevent further negative associations with each other.
• Gradually reintroduce the cats using counterconditioning and desensitization, closely monitoring for signs of stress and anxiety.
• Learn and monitor body language. At the first sign of aggression, stalking, or bullying, positively redirect the aggressor cat with a toy or treat away from the other cat.
• Avoid punishment, including yelling, spraying with water, loud noises (shaking cans of pennies, clapping), or hitting. Punishment can cause the cat to associate negative feelings with the other cat, escalating fear and anxiety and damaging the human-animal bond.