Intercat aggression is more a description of what is happening rather than a diagnosis. There are many reasons why cats interact aggressively. They may include:
- Fear of the Other Cat in the Household
- Dominance Struggle
- Play Aggression
Treatment of intercat aggression really depends on which of these situations exists in the household. For example:
Fear of another cat may be dealt with by simply confining the cats away from one another when unsupervised. Use of a bell on the aggressor's collar may help signal the victim when the aggressor is approaching. Interrupting inappropriate aggression with spray bottle of water and vinegar. Rewarding with treats or play any observation of calm, relaxed behavior when the cats are in each other's presence. Use of multiple litter boxes distributed throughout the house may give the victim more options to eliminate without increased risk of facing off with the aggressor.
A couple notes here. 1)The rule of thumb for litter boxes is 1 box per cat in the household plus one additional. These should be spread out throughout the house on multiple levels to increase three dimensional space for the cats. Do not group boxes in one area. You are essentially just creating one LARGE litter box t=rather than multiple ones. 2)In a situation in which one cat is stalking another, often the use of a covered box is not indicated. The aggressor many times will wait outside the box and pounce on the unsuspecting victim as he/she emerges from the covered box. For this reason, it is advised to use only open litter boxes in this circumstance.
Dominance Struggles are dealt with by again providing an appropriate litter box environment. Using aversive sprays and rewarding appropriate behavior as noted above. Use of food desensitization trials in which the cats are fed at a great enough distance apart then gradually (a few inches per day) the food bowls are brought closer together. A word of caution here. You should begin with each cat in a carrier and bring the carriers closer together. Then repeat the process but now with the doors of the carriers open. Then, finally, with the cats out of the carriers. It is wise here to fit both cats with harnesses and leashes during the steps in which they can gain access to one another. Holding the leashes or securing them to an immovable object will help prevent injury. In order to increase the motivation of the food, only feed the cats during the trials and feed something very palatable (ex. canned diets). Keep cats separated when unsupervised. If all else fails, placement of one of the cats may be indicated.
Play Aggression is merely the normal "ruff and tumble" activity that occurs with kittens. Kittens must learn predatory and hunting behavior and the best learn this through pseudo hunting activities with each other. To the uninitiated, this can seem to be the real thing with hissing, spitting and pouncing. The key is that the posture is different than real fighting. Ears are up and relaxed, tails are swishing in a non-chalant manner, and the kittens readily re-engage their activity with each other rather than run off and hide. There is rarely a "stand offish" display by one kitten with the other leaving the scene. Do not interfere unless there is a history of injury occurring.
Territoriality is merely the establishing of defined, protected territories within a living space. This is seen in the outdoors by males establishing "harems" of females in various areas and regularly visiting these sites to protect them against intruding males. In the home environment, the resourses guarded include food, elimination areas and access to attention from the humans in the household. Again, attention to litter box placement is critical, appropriate punishment and reward, and belling the aggressor are all helpful strategies. In severe cases, placement of one of the cats may be necessary.