A cat may become fearful, anxious or highly aroused in situations that are unpredictable, those that have been previously
fear evoking, or when there is a perceived threat. The cat's response can be to freeze and posture, attack, or flee. In addition,
when there are competing motivations (conflict) or if the cat is frustrated from achieving its goal, the aggression may be
redirected toward another individual who is more immediately accessible or is more vulnerable than the stimulus. Highly fearful
or aroused cats can take hours to days to return to a normal baseline level.
Fear and anxiety in cats may arise as a result of genetics, inadequate early exposure, and unpleasant events or experiences.
There may also be other factors influencing the pet's aggression including illness, pain and irritability, territorial behavior,
and hierarchal relationships. When exposed to a fear evoking stimulus, the consequences of the pet's actions further aggravates
the problem in that if aggression is successful at chasing away the threat it has been reinforced (negatively). On the other
hand if the aggressive display leads to fear, retaliation or punishment, the pet's fear and aggression with each further exposure
is likely to be heightened. Therefore, in order to successfully treat aggression, the pet's level of fear, anxiety or arousal
will need to be reduced (e.g. with desensitization and or drugs) so that learning can occur.
Aggression can occur toward cats that live in the same household, especially new cats coming in to the territory. Cats recognize
colony vs. non-colony members. In fact, aggression is typically exhibited by members of a cat "colony" toward unfamiliar cats
that are not members of the colony. With persistence some cats may be integrated into an existing colony but this is a gradual
process that takes many interactions. The same is likely to hold true therefore, when introducing a new cat into a household
where one or more cats is already present. Another situation is when one cat is away from home (perhaps for routine surgery,
boarding or being lost) and aggression is exhibited when the cat is brought back into the home. This aggression may be induced
by fear or unfamiliarity (perhaps due to a change in odor, visual appearance or behavior).
In the wild, colony size is determined primarily by food resources which are, of course not likely to be an issue in a family
home, if sufficient food and feeding stations are provided. However, within a home there are physical restrictions on space
and dispersal. Therefore providing sufficient resources such as food, resting areas and litter boxes can help to insure a
more harmonious relationship. If a cat is fearful of being disturbed when entering the litter box, housesoiling may arise.
In addition, cats may attack others in the household that act fearful or more vulnerable. Since appeasement behaviors and
postures are generally not part of the cats repertoire, when aggression begins there may be no way for it to naturally dissipate.
In a recent study of 128 households with multiple cats and 124 households with a single cat, about 50% reported fighting when
a new cat was introduced into the home. Number of cats, age and sex were not associated with fighting. Ongoing fighting was
associated with aggressive or unfriendly behavior by either the new or resident cat at the first meeting (e.g. scratching
and biting), and outdoor access. In most cases it was the new cat that initially displayed fear or aggression, while the resident
cat was more likely to try and initiate play.
Fear and aggression might be prevented or minimized if cats have received early socialization. Although cats may be born with
the capacity to learn social skills, experience with their own and other species is necessary during early socialization (first
2 months). Therefore, adopting multiple cats of different ages or insuring contact with other cats during kittenhood and the
juvenile period, can help prevent the cat from having dysfunctional relationships with other cats, which might include aggression,
fear, and failure to understand intraspecific signaling. Kitten socialization classes are another option.