Cat Aggression: Other Cats | Winnipeg Humane Society
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Cat Aggression: Other Cats

Cats with aggression problems may never be best friends, but can often learn to mutually tolerate each other with a minimum of conflict.

Inter-Cat Aggression

Aggression between cats happens when two or more cats have an unfriendly and hostile relationship with each other. It can happen between cats that are unfamiliar with each other. It can also occur between familiar cats that have been living together in an apparently good relationship. Two cats might have come upon each other in an outdoor environment, the cats could be challenging each other for status or territory, or there has been introduction of a new cat into an existing cat’s environment. Sometimes redirected aggression can happen between two familiar cats in the home.

It can be confusing when two cats who previously appeared to be getting along escalate to fighting. Cats generally do not want to engage in physical fighting, but rather prefer to communicate through posturing or intimidation. Posturing can include “puffing up” and intimidation can be activities such as pushing the other cat out of the food bowl or guarding the path to the litter box. These subtle signs and behaviours allow cats to avoid physical fights that could result in injury. But humans often miss these signs because there are no obvious signs of aggression.

Sometimes cats just have misunderstandings and temporary conflict, just like people. But if there is an ongoing pattern of intimidation or there are daily occurrences of growling, hissing, and/or physical fighting you will want to address the source of the conflict. You might need to enlist the assistance of a professional such as a veterinarian or behaviour specialist that is knowledgeable about cat behaviour. You cannot wait it out and hope it will get better. It won’t, it will only get worse.

We can’t predict how a pair or group of cats will tolerate each other. Cats are very territorial and there are cats that might never be able to share their house with another cat. Such cats would do best in a single cat situation. Other situations can be resolved with guidance, time, and patience.

The method of dealing with inter-cat aggression will depend on the underlying cause. Some common causes of inter-cat aggression are explained below.

Redirected aggression

Redirected aggression occurs when aggressive behaviour is directed toward an animal that didn’t initially provoke the aggression. The cat cannot get to the source of his upset and so turns to the closest target, which could be your other cat or even you. For example, if your cat sees another cat outside, the window will prevent him from attacking the outside cat. So he turns and attacks whatever animal or person is close by.

This type of aggression is not easily recognized because you may never see the actual source of the cat’s agitation. Once upset, a cat can stay reactive for quite a while. Depending on how severe the aggressive encounter was, the cats could remain hostile toward each other for some time after the episode.

Territorial aggression

Cats are more territorial than dogs and females can be as territorial as males. What your cat views as his or her territory can vary from a part of your house to an entire neighborhood. If a cat feels that his/her territory has been invaded, he/she will defend it.

Territorial aggression can occur when a new cat is brought into a household or when a kitten reaches maturity. A cat can be be territorially aggressive toward one cat in a family but friendly to another cat. If the aggressive cat chases and ambushes the other cat this could be territorial aggression. If there is contact between the cats there will be hissing and swatting.

Territorial aggression can occur when one cat returns from the veterinarian. Cats use scent for recognition and when a cat returns to the home and doesn’t smell like herself, she can become the victim of territorial aggression.

Defensive aggression

When a cat is not able to protect himself from what he considers an impending attack, he can become defensively aggressive. Defensive aggression can occur when a cat is being attacked or threatened with attack by another cat. It can also occur when a cat is punished. He feels threatened or afraid and so he defends himself.

You can recognize defensive aggression by the situation in which it occurs as described above, or by his posture. Defensive cats crouch with their legs under their bodies. The ears are back and the tail is tucked. The cat could be rolling to its side. This is not the same as a submissive dog rolling on its back. When a cat is on its back it has full use of its weapons – claws, especially on its hind feet, and his teeth. If you continue to approach a cat displaying these postures he will likely attack.

Inter-male aggression

Adult male cats will threaten and sometimes fight with other male cats. These behaviours occur as sexual challenges over a female or to achieve a higher position in the cats’ loosely organized social hierarchy. There is a lot of ritualized body posturing, stalking, staring, yowling, and howling during this type of aggression. Attacks can be avoided if one cat opts to walk away.

If there is an attack, the attacking cat will jump forward and direct a bite to the nape of the neck of the other cat. The other cat might fall to the ground on his back and attempt to scratch the attacker’s belly with his hind legs. The cats will roll around scratching, biting and screaming, but then suddenly stop and go back to posturing. The fight could resume or the two cats could walk away from each other. Cats don’t usually severely injure each other during these fights, but it is a good idea to check for puncture wounds. Intact males are much more likely to engage in inter-male aggression than neutered males.

How to address the aggression

Provide an environment in which the cats feel safe and secure. If the relationship between the cats is tense but not dangerous you can implement behaviour modification to make them feel more comfortable with each other. You can create positive associations to work toward the cats getting along, but this will require some management and changes in the environment. Your attitude and behaviour will have an effect on your cats’ attitudes and behaviour toward each other. If you anticipate something bad happening your cats can pick up on it.

What not to do:

  • Don’t let them fight it out. Cats don’t work things out and the more often they fight, the more difficult it will be to resolve the situation.
  • Don’t punish one cat for its actions toward the other. You can interrupt the behaviour but if you use punishment you only reinforce that the other presence of the other cat is bad.
  • If your cats are engaged in a fight, don’t try to pull them apart and risk injury to yourself. Even though cats are smaller than many dogs, they can severely injure you with their teeth and claws. It is better to startle the pair by making a loud noise, clanging metal pans, blowing a whistle or horn, or throwing something soft such as a pillow or blanket.

What you can do:

  • If any of your cats are intact, spay/neuter them. Even if one of your cats is intact it can affect all of your cats.
  • If you notice a sudden change in behaviour and your cat has not recently seen a veterinarian, make an appointment. Behaviour changes can be an indication of medical problems.
  • Separate your cats and reintroduce them again, slowly. The cats might have to be separated for several days in order for a successful re-introduction. Introduce them as though they have never met. You want your cats to enjoy years in each others’ company so don’t rush the process. Please refer to the article on Cat Introductions.
  • If the case is extreme you might need to consult your veterinarian about medication and work through a behaviour modification program. Medication is meant to be a temporary and not permanent solution and should be used along with behaviour modification.
  • If there have been changes in your household that could be causing anxiety, there are pheromone sprays and diffusers available. Many veterinarians carry these for sale.
  • Make note of resources that could be causing competition or conflict. If the cats are sharing the same food dish, they could be competing for food. Give each his own bowl. If you have two cats, you should have at least two litter boxes. Ideally you have one box per cat, plus one more. In different locations. Are there multiple scratching posts? There should be more than one.
  • Provide vertical space. Cats need a safe place to perch and view their world. For a confident cat a high perch provides an opportunity to display high status so he doesn’t resort to aggression. A vertical perch is important for a fearful cat as he can see a threat approaching. He will feel safer.
  • Build positive associations by making good things happen when your cats are together. Feed special treats when they are together. Feed their meals in the same room but from separate bowls. Provide play opportunities when they are together. You don’t want them to compete for the same toy so ideally there will be a person and a toy for each cat. If there isn’t a second person available, you can use two similar wand type toys, one for each cat.
  • Be equally attentive to each cat. They both need your love and attention.
  • Provide an enriched environment with lots of interesting things to do. They love to hunt and explore and be active. If they are happy in general they are more likely to be happy with each other.
  • Try clicker training. Yes, cats can be trained! A clicker makes a noise like a cricket and the sound is used to mark (identify) behaviours that you want to reward. When you pair a “click” with a treat, the cat learns to associate the sound of the clicker with the treat. You can use this to reward the cat for calm and positive behaviours toward the other cat.

Changes don’t happen overnight

It has probably taken some time for this relationship to deteriorate, so expect that it will be necessary to invest time and effort into repairing it. It takes time to rebuild trust and it can’t be rushed. It has to happen on your cats’ schedule and not yours. Celebrate small positive changes, they will begin to add up.

If the relationship has deteriorated and the cats can’t be in the same room at all and there is a risk that someone could get hurt you will need to try a reintroduction. If what you are doing isn’t working try separating the cats and introduce them again – as though they haven’t met before.

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