CVC Highlight: Why are my cats fighting?

A sudden onset of aggression between cats in the home can be shocking to cat owners. A traumatic event can trigger aggressive behavior between previously compatible companions. When aggression develops suddenly, the first course of action is to carefully question the owners about any recent changes in routine or any stressful events. A house guest, a small painting project, or a new puppy next door may all seem innocuous yet can trigger serious aggression between resident cats.

When cats present for sudden onset of aggression, examine both the aggressor and victim for an underlying medical cause. Relevant laboratory work may be indicated before concluding that the diagnosis is behavioral.

DEFINING THE PROBLEM

Several types of aggression occur between household cats.

Status-based and territorial aggression

Status-based and territorial aggression may first appear as one of the household cats approaches social maturity. A mature cat can be threatening to the original resident cat. The up-and-coming cat may pursue access to valuable resources or may behave aggressively in an apparent attempt to establish an exclusive territory.

Fear-based aggression

A fearful cat quickly becomes a victim, triggering a pursuit. Once the flee-chase-flee cycle is established, it can be difficult to interrupt. Owners should ensure ample safe access to all resources such as food, water, and litter boxes.

Redirected aggression

Redirected aggression occurs when a cat cannot gain access to the primary trigger. Sometimes an external trigger can be identified, such as a stray cat just outside the window. Trapped inside, the house cat cannot access the stray and, instead, directs its aggression toward the companion cat.

Redirected aggression can progress to fear-based aggression. A cat that is the recipient of an unexpected attack is likely to become fearful. When a victim runs away in fear, a flee-chase-flee cycle ensues. On the other hand, some frightened cats assume a more assertive posture, initiating a chase rather than running away.

TREATMENT STRATEGIES

Environmental modification and management

If the level of aggression or fear is relatively low, environmental modification alone can be therapeutic. Owners should ensure that both cats have easy access to all resources including food, water, and litter boxes. Cat trees and shelves should be available to provide comfortable resting places on all levels.

For most cases, it is important to physically separate the cats when they cannot be supervised until treatment has been completed. This not only reduces the risk of injury but prevents reinforcement of aggression and fear. Be aware that for some cats confinement is stressful and cannot be accomplished without either desensitization or pharmacologic intervention.

It is important to allow each cat plenty of time to explore the entire home. While one cat is confined, the other should be free to roam, and vice versa. Since cats in tight social groups routinely rub against each other, thereby distributing “friendly” pheromones, instruct owners to rub their cats' cheeks with a common towel.

When there is a known inciting event, as is common with redirected aggression, the owners should separate the cats for several days before attempting any reintroduction.

Behavior modification

Systematic desensitization and counterconditioning. For safety during reintroduction, the cats should be exposed to each other through a barrier such as a screen or tall gate. If the cats begin to exhibit friendly posturing, perhaps attempting to gently bat at one another or rub faces, then they are likely to remain friendly. If they hiss or growl or become piloerect, they need to be separated again, and a systematic desensitization and counterconditioning (DSCC) should be started.

Additional behavioral issues as clues to diagnosis

While treating intercat aggression, you should identify and manage concurrent behavioral concerns. Examples include anxiety or aggression that may be exhibited in other contexts. Urine marking is a common consequence of intercat aggression. Sometimes, urine marking is the first or even the only sign that suggests there might be friction between household cats.

To accomplish DSCC, the owners should offer each cat attention and special food initially far from the barrier until the cats appear comfortable. After a few successful sessions, they can move a bit closer together. When a session is over, the cats should go back to their respective confinement areas.

Over time, the cats can be desensitized to each other's activities. For instance, owners can play with the cats to increase activity. DSCC can also be used to reduce the fear of known triggers for aggressive events.

Remind owners to be prepared for an emergency. They may be able to interrupt a fight with a large water gun or a heavy blanket. The plan should be to end all sessions on a positive note.

Response substitution. For social cats with a low level of arousal, response substitution can be used. A cat can learn to exhibit a new response to replace chasing. For example, owners can use clicker training to teach a cat to jump up onto a cat tree. Once this skill has been mastered, the owner can prevent a chase by sending the cat to the tree for a treat.

Pharmacologic intervention

Cats with abnormal levels of anxiety or aggression and cats that exhibit multiple problematic behaviors may benefit from anxiolytic medication. The selective serotonin reuptake inhibitor fluoxetine is well-tolerated and can reduce both anxiety and aggression in many cats. Before prescribing any medication, consider and discuss the risks as well as benefits with the owners. Client understanding and consent are essential since most psychotropic medications are not labeled for use in cats.

FOLLOW THROUGH TO RECONCILIATION

Encourage clients to work slowly but steadily. Many owners are overwhelmed with the task of supervising cats and studying cat postures. Regular follow-up support will encourage them to persevere. Ask owners to return in seven to 10 days for a recheck appointment. This visit will offer an opportunity to address any difficulties with the implementation of either the safety protocol or the behavior modification plan. In many cases, the prognosis for controlling intercat aggression can be good. However, some cats are not compatible and owners should be prepared to enforce a permanent separation if necessary.