The Mind of Your Cat: 12/03

Question: I have two sweet female cats – one Ive had for three years, the other for one year. Normally they get along pretty well, but for the past three days, theyve been literally at each others throats. Every time they get around each other they start hissing and yowling, and then the older one goes after the younger one. The younger one is so scared that she just crawls low on the floor. I have been keeping them in separate rooms. I wanted your opinion on the matter because I am sure it will happen again.

Answer: You may be right: It could happen again. The scenario you describe most likely represents a case of redirected aggression. The term redirected aggression is used to describe a situation in which aggression is directed not toward the original stimulus but toward a nearby person, animal or object. There are two points in your history that cause me to suspect that redirected aggression may be occurring.

First, you mentioned that your cats get along fairly well most of the time. That would indicate that they are comfortable in one anothers presence and that the occasional hiss or growl does not result in sustained aggression. The second point that supports redirected aggression is that you described the typical bout of problem behavior as lasting several hours. That would indicate a more sustained level of discomfort, but not enough to impact the day-to-day relationship between the two.

Unfortunately, as you have noticed, the situation does not always resolve so quickly. In some severe cases, it may take weeks or months before the cats return to their previous level of comfort with one another. How can that be? Cats that exhibit redirected aggression seem to be easily aroused. Once frightened, they often exhibit fight rather than flight behavior. When an animal is frightened, it may not pay appropriate attention to the details of the situation.

Heres an example: Imagine your easily-stimulated cat is sitting on the window ledge, and she spots a stray cat gazing up at her window. Were it not for the pane of glass, she might leap toward the intruder. Meanwhile, her companion house cat might innocently approach to investigate the reason for her housemates excitement. Suddenly, the aroused cat turns from the window and attacks her housemate. Because of her high level of arousal, she would not pause to check the identity of her victim.

What happens next? If neither cat is terribly fearful, then the victim cat might run away, but recover quickly, and exhibit no concern the next time she sees her attacker. And the aggressor cat might be able to recover enough to determine that her housemate is no longer a threat. Healing can occur in minutes to hours.

But, there are other possible outcomes, as you have learned. First, the victim – particularly if she is a bit fearful herself – may hiss and flee upon subsequent encounters with her attacker. Second, the attacker – particularly if very fearful – may have formed an association between the original threat and her housemate. Thus, seeing her housemate now becomes as scary as seeing the original stray outside the window, and further attacks will occur.

Of course, in the absence of a complete behavioral history, it is not possible to determine a diagnosis with certainty. Other types of aggression, including fear-based or status-based, could result in a change in the household dynamics. Be sure to have both cats examined carefully to rule out any underlying medical problems.

Illness may increase aggression, as a sick cat may be less tolerant of fear-inducing stimuli. In addition, certain disease processes can change the scent and or the behavior of a cat, eliciting fear-based aggression in a companion cat.

A diagnosis of redirected aggression would be supported if you were able to identify a potential trigger for one or more of the episodes. Stray cats are often spotted just prior to bouts of redirected aggression. Other environmental triggers may include nearby construction or even fireworks.

Redirected aggression can be treated. Behavior modification can be used to reduce reactivity, particularly if a trigger can be identified. In many situations, the cats need to be gradually and system- atically reintroduced just as if they had never met one another. And in certain cases, anxiolytic medication may reduce the intensity of fear, improving the response to behavior modification.

You did the right thing. Always separate the cats at once, and do not rush to reintroduce them. It is better for them to spend a day or two apart than to allow the cats to encounter one another only to repeat the hiss/chase/flee cycle. And of course, if the situation does not resolve uneventfully, your veterinarian should be contacted so that a behavior consultation can be arranged.