In my practice, aggression trails only housesoiling as the principal behavior problem cat owners seek help in treating. The
seriousness of the problem can vary from a cat that hisses and avoids social interaction to one that attacks people or other
animals. To help such cats and the families that own them, veterinarians must rule out medical problems, take a complete history,
make a sound diagnosis, and provide sensible advice.
Although medical problems are not common causes of sudden, severe expressions of aggression, it is important to first rule
out medical reasons for any aggressive feline behavior by performing physical and neurologic examinations and laboratory tests,
such as a complete blood count, a serum chemistry profile, and thyroid function tests. Pain can lower the threshold for aggressive
behavior, so any type of physical discomfort should be noted during the examination. Bizarre manifestations of aggressive
behavior or unusual neurologic signs may warrant brain-imaging procedures.
BASIC RECOMMENDATIONS TO OWNERS
Keeping an aggressive pet in the home always presents some risk. Never suggest to clients that treatment will eliminate any
chance for future injuries. Make sure clients understand that rehoming (depending on the severity of the problem) or euthanizing
aggressive cats may be the most prudent choice and that they are not obligated to keep cats that may seriously injure someone.
Factors that should be considered when assessing danger include predictability (whether triggers for aggression are known
or warning signs are present), bite inhibition (degree of bite pressure, intensity of aggressive behavior), and the family
makeup (ages of family members and their cognitive capability, complexity of the home environment).
You can usually help make the situation safer without getting into complicated treatment recommendations by giving owners
some simple, common sense guidelines:
- Stop petting the cat on the head, belly, back, or any other area that triggers an aggressive response.
- Confine the pet when visitors are in the home, when children are playing, when the dog is awake, or in other situations that
lead to aggression.
- Don't touch the cat when it sits in the windowsill and watches outdoor cats.
- Separate fighting cats in different areas of the home.
- Stop hitting or yelling at the cat.
SPECIFIC TYPES OF FELINE AGGRESSION
Several types of feline aggression exist (Table 1), caused by many stimuli. It's important to identify an individual cat's aggression stimulus because treatment varies depending
on the aggression type.
Table 1. Types of Feline Aggression
Fear-induced aggression (defensive aggression)
When a cat encounters someone or something it perceives to be a threat and its escape is impeded, the cat may exhibit defensive
behavior and attack until escape is possible.1 The less familiar the cat is with the stimulus, the more heightened the cat's fear response is likely to be. Signs of
fear-induced aggression include dilated pupils, ears flattened against the head, limbs tucked under the body, low body position,
leaning away from the stimulus, batting with the paws, hissing, spitting, and growling. If the cat's aggressive displays drive
away the fear-eliciting stimulus, its behavior is negatively reinforced.2
Genetic and environmental influences can contribute to this problem. Some cats are born with timid personalities, and kittens
that have not been adequately socialized during the first two or three months of life are also likely to be fearful of people
and aggressive when approached or handled.3 Cats that have aversive experiences associated with people or animals may become fearful and may exhibit avoidance and aggressive