Behavior Counseling Aggression - Introduction

What is aggression?

Aggression is defined as threats or harmful actions directed toward another individual and can include threat displays, lunging, growling, snarling, snapping, and biting.

"In animals, aggressive behaviors are a means of communication."

In animals, aggressive behaviors are a means of communication. Cats use aggressive displays, threats and attacks to resolve competitive disputes over resources (territory, food) or to increase their reproductive potential, or to escape threatening situations. "Aggression" describes the behavior, but does not give any information about underlying motives or causes. Aggression can have multiple motivations.

How is aggression classified?

Aggression can be subdivided into type based on intended victim, body postures during aggression, the pet's health, and other factors such as the resource the animal may want, estrus status of animals involved, and location of the aggressive encounter. When classifying aggression, it is important to consider the factors surrounding the initial aggressive event, since over time the effects of learning (consequences), including the actions of the owner and the stimulus (e.g. how the person or other pet retaliates or retreats), will affect how the aggression is displayed.

"In cats, the function of the aggression is most commonly used as the basis of classification."

Ethologists, persons who study animal behavior, use the term agonistic to refer to the behavior of animals (usually of the same species) that involves conflict or contest. These encounters can involve fighting, escape, dominant, and submissive gestures and posturing. Aggressive behavior can also be divided into offensive (going after the other individual) and defensive (defending yourself from a perceived threat) aggression.

In cats, the function of the aggression is commonly used as the basis of classification. Common diagnostic categories used in veterinary behavioral medicine include fear-induced, conflict aggression, possessive, protective and territorial, predatory, social/conflict/dominance (status-related) related, pain-induced, parental, redirected, play, intermale, interfemale, and pathophysiologic (medical) aggression. Aggression can also be classified by target: aggression toward familiar people, aggression toward unfamiliar people, aggression toward familiar animals, and aggression toward unfamiliar animals.

Note that there is no one single cause of aggression. In addition, an individual pet can display one or more forms of aggression and multiple factors and stimuli may combine to push the cat to a point where aggression is displayed.

Are aggressive cats abnormal?

"Aggressive behaviors may be "normal", but when they result in human or animal injury, the behavior is dangerous and unacceptable."

Aggressive behaviors may be “normal,” but when they result in human or animal injury, the behavior is dangerous and unacceptable. Human safety must always be a primary consideration when discussing aggression. It is estimated that from 2 to 5 million human bite wounds occur annually across North America. Most people are bitten by animals they own or that are familiar to them.

Some aggression in cats may have abnormal components to it, especially when the pet is excessively anxious or unable to control the initiation, termination, or intensity of its response. These problems may arise from genetics, lack of sufficient socialization, insufficient maternal care, or exposure to excessively fearful events, particularly during early development. Although in some cases, medical health problems and degenerative changes may be present in an aggressive animal, they may or may not contribute to the aggressive behavior.

What does an aggressive cat look like?

Often, the first sign is a dilation of the pupils (the dark part of the eye) and rapid side-to-side movements of the tail. This may be accompanied by putting the ears back or to the side and hissing or growling. In addition, the cat may "swipe" at the intruder with a front paw, either with the claws sheathed or exposed. Sometimes the cat will gather its legs under itself and appear ready to pounce. If the intruder is not too close or begins to leave, the aggressive encounter may end.

Cats have other more dramatic body postures that signal "go away." Cats frequently try to enhance their size and ferocity to make the threat more menacing. They will do this by turning sideways to the intruder, arching their back, holding the tail upright or straight down, and having their fur stand up. They may hiss, growl, and yowl at the same time. In other situations, a cat may crouch down, tail switching back and forth with the ears tight against the head, again with accompanying vocalization. A cat anticipating a fight may roll onto its back with claws extended, ready to fend off a foe.

How should I respond to these behaviors?

The distance between the animal and the intruder can be influential in determining the appropriate response. This is often called the "flight" distance. If the intrusion is far away, the animal may choose to flee; if the intrusion is very close, the animal may choose to fight, assuming flight would be unsuccessful. If flight is inhibited, such as when a cat is cornered or tied up, aggressive responses become more likely.

"When approached rapidly, a cat may go through the stages of aggressive behavior very quickly and bite without the intruder being able to react."

On their own territory, some cats are more likely to fight than retreat. When approached rapidly, a dog or cat may go through the stages of aggressive behavior very quickly and bite without the intruder being able to react. Cats that are mildly fearful may calm down if the intruder shows no fear, waits until the pet settles, and then offers a food reward. Reaching for a cat while continuing to advance is likely to provoke further aggression.

Most cats will flee if given the opportunity. However, some cats will stand their ground and will scratch or bite if reached for. Bites are most likely if the cat is cornered or restrained and cannot escape, but some bold, confident cats will exhibit territorial displays toward intruders on their property in much the same manner as they might chase another cat out of the territory.

In some cases, despite standing still, avoiding further advance or retreating, the aggression continues. Because aggression depends on the situation, the pet’s level of motivation, previous experiences, and the type of aggression, it will be necessary for you to provide a detailed history to your veterinarian so that an accurate diagnosis and appropriate treatment plan can be established in these cases. Details on the diagnosis and types of aggression in  cats can be found in separate handouts.