PROBLEMS OF AGGRESSION
Before trying to treat a problem of aggression in a cat, it is important first to identify it correctly. The contexts in which it occurs, when it first occurred and the cat's body postures and vocalizations at the time are crucial. The cat's age and sex are also relevant, as are the characteristics of the victims including, if they are cats, their age and sex. It should be borne in mind, however, that what started out as one type of aggression can, over time, change into another.
Predatory behaviour differs from other forms of aggression in that it tends to be silent and consists of sequences of behaviour, such as stalk, pounce, grasp, bite etc., which are not found in the same sequence or expressed in the same manner as in social encounters with other cats or people. In such social encounters, aggression is part of a system of communication between the two parties involved. When hunting, the object is not to communicate with the prey, but simply to capture, kill and eat it.
If they have the opportunity, most cats will hunt and kill small animals such as birds and mice, although some are more enthusiastic and skilful hunters than others. Although most owners are philosophical and learn to live with this aspect of a cat's instinctive behavioral repertoire, some are upset by it. It may be some comfort to them to reflect that cats evolved into predators over millions of years, long before they were domesticated.
Certainly owners should not be encouraged to believe that they can abolish their cats' hunting behaviour, although they might be able to reduce its effectiveness. Cats are predominantly crepuscular hunters: keeping them indoors at dawn and dusk, when rodents tend to be active, may reduce the carnage to some extent. Protecting fledglings during the nesting season of garden birds may prove more difficult. Feeding a cat before favorite hunting times may reduce its eagerness a little. Feeding fresh gristly meat still attached to the bone may increase the effect somewhat, although a full stomach probably reduces the number of animals killed because it makes the cat sleepy or slower, rather than because it directly affects the cat's motivation to hunt. Attaching a bell to the cat's collar may allow more alert and agile victims to escape. It is usually best, however, to encourage clients to tolerate and manage this aspect of their cats' behaviour, rather than trying to alter it. Owners may be less upset by their cat's hunting if it does not bring the results into the house. They may be able to deter the cat from doing this by hissing at it when it comes indoors with its prey. They may solve the problem by simply keeping the cat indoors where it is safest as well as protecting other creatures.
Play aggression may contain components of intra-species aggression, but often most closely resembles predatory behaviour. It differs from it in that the components may appear jumbled up and out of sequence and the attack is, to some extent, inhibited. Thus the victim may be stalked and pounced on but not "killed," the force of the bite being reduced and claws retracted. However, as with true predatory behaviour, the attacks are seldom accompanied by any vocalization.
Cats may play with toys and with each other; they may also show play aggression towards their owners. Studies have found play aggression to be the most common form of aggression directed at people. Although this type of aggression is most common in kittens and young cats, mature cats may continue to try to play in this way. Owners may find this alarming, especially if they do not understand their cat's behaviour. Even an inhibited attack can cause some injury, particularly to young children, the elderly or the infirm.
Such attacks are almost always triggered by movement of the victim. The cat may lie in wait, perhaps in a favorite place, to ambush people as they go by. He may also have a favorite victim/playmate target. Owners should not try to deter the cat from this behaviour by counterattacking with attempts to strike it or push it away. There is a danger that, even if the cat is not alarmed by these actions, it may interpret them as reciprocal play. If it is alarmed, it may show defensive aggression, thus making the problem worse.
Confining or isolating the cat is unlikely to improve matters. Playful cats need to be played with. Inexperienced owners may need advice on suitable toys and how to move them erratically in order to elicit and sustain play behaviour. Owners of these cats should be encouraged to play with them more frequently. More specifically, they should use toys to deflect attacks directed towards themselves. The more accurately the time and place of these attacks can be predicted, the greater is the chance that they can be prevented. Owners might, for example, throw a toy ahead of them as they pass the cat's favorite spot for an ambush. They might also throw a toy to divert the cat's attention if it becomes overexcited.
Typically entire tom cats engage in instinctive competitive behaviour. However, Hart (Hart and Cooper, 1984; Hart and Barrett, 1973) has found that 44% of castrated male cats fight with other cats at least occasionally and 10% engage in serious fighting. The proportions engaging in intermale aggression must be less than these, however, as the same study found that 30% of female cats also fight at least occasionally.
Inter-male aggression can normally be distinguished from other types of fighting by the characteristic threat ritual which precedes it. Typically the aggressor assumes a confident stance. The tail may be held stiffly up, turning down at the end and twitching. The ears face forward and the head may be slightly tilted from side to side. There is usually a good deal of growling, spitting and meowing. This threat ritual may last for some time, with the cats moving slowly towards or away from each other. The fight, if it occurs, though often dramatic and accompanied by screaming, is usually comparatively brief. There may be several rounds of threat and fight before the encounter is over. The fights seldom result in serious injuries, except when the back feet are employed to rake at the stomach of the opponent. More often, the chief danger to the fighting cat's health is from subsequent infection of the puncture wounds and transmission of fatal viral diseases (FIV, FIP, FeLV) arising from bites.Behavioral treatment is unlikely to be effective in reducing this type of aggression. Overall, synthetic progestagens have been found to reduce fighting in 75% of cases. Though it is likely that they are particularly effective in reducing inter-male aggression, they will only be effective for the period of prescription. As soon as-such drugs are withdrawn, the cat's original competitiveness towards other toms will return. Given the potentially serious side effects of these drugs, a fighting cat's interests might be better served by keeping him indoors where he is safest.
SOCIAL AGGRESSION BETWEEN CATS SHARING A HOUSE
Sometimes, in multi-cat households, one cat may take a dislike to one or more of the others. It will growl or hiss at its victims on sight. It may even mount, attack or pursue them aggressively out of the room or the house at nearly every encounter. Such aggression is commonly referred to as "territorial" aggression, but this term makes a questionable assumption about the aggressor's motivation. The aggressor may attack only one cat in a multi-cat household and, while the victim is usually a newcomer, it may, on occasion, be a cat with which the aggressor has previously lived on good terms. Such disputes most commonly arise when either cat reaches maturity, at about 8 - 18 months of age. The victim may become withdrawn and fearful, taking refuge outdoors or in inaccessible corners of the house. Alternatively, it may develop a strategy of defensive aggression to deal with the threat and serious fights may occur, resulting in injury.
It is important to distinguish this type of aggression from either defensive aggression or redirected aggression. Aggression which builds up between two cats slowly over time, rather than erupting suddenly, is not redirected aggression. The same usually applies to attacks which, though they have a sudden onset, are directed towards a new arrival in the household. Attacks which involve chasing the victim even when it is in retreat are not defensive aggression.This type of aggression is apparently prompted by intolerance of an individual cat. Providing the victim with a safe haven in the house is vital to protect it from injury and to maintain a good relationship with the owner and with any other friendly house cats. The aggressor can then sometimes be systematically desensitized to his victim. The two cats should be kept apart except for supervised treatment sessions where they are exposed to each other in conditions which do not provoke hostility. Thus, to begin with, the rooms in which they are kept might be interchanged, so that the aggressor is desensitized to the smell of his victim. They then might be allowed to see each other while separated by a glass or mesh door or window. Alternatively, the cats may be placed in separate wire mesh cages where they can see each other. The cages may then be gradually brought nearer to each other as mutual tolerance increases. Feeding both cats during this exposure may improve their tolerance: the effect may be enhanced by withholding or delaying a meal to ensure that both cats are hungry before controlled introduction sessions. DEFENSIVE AGGRESSION
Defensive aggression occurs when the cat perceives itself to be under a threat from which it cannot escape. This threat may come from dogs, people or from other cats. This type of aggression may be recognised by the typical body postures which accompany it.. Also, the defensively aggressive cat only attacks when approached: it does not seek out the source of the threat nor pursue it if it withdraws.
Sometimes the nature of the perceived threat is obvious, as when the cat is attacked by a dog or another cat. Sometimes the object of the attack is harmless (e.g. a startling noise) and the aggression is a phobic reaction (see phobias). As mentioned above, defensive aggression can complicate other problems of aggression. Complex problems can also arise with, for example, two cats becoming defensively aggressive towards each other. This may begin when one cat inadvertently startles another or when both are exposed to the same external threat which both perceive as originating from the other. Defensive aggression should be treated in the same way as phobias, with systematic desensitization and supportive drug therapy if required.
Defensive aggression is probably the commonest type of aggression observed in the veterinary consulting room, and most likely to be encountered when the practitioner tries to approach or restrain the cat or to carry out some uncomfortable procedure. While most investigations are relatively quick and carry little risk of long term behavioral impact on the cat, the risk to the veterinary surgeon and nursing staff can be high. Any attempt to "dominate" the defensively aggressive cat is entirely inappropriate and will only exacerbate the problem on the cat's next visit to the surgery. Instead, the cat should be approached in as non-threatening and slow a manner as possible and restrained gently but firmly. Specialised muzzles which hood the cat can have a calming effect. These should be fitted by the owner in the waiting room or even at home before setting off for the surgery. In addition, placing the cat on a piece of carpet on the examination table and pulling it slightly backwards will encourage it to take hold of it with its claws and keep them safely occupied during dorsal or facial examinations. Two people are usually required for speed of treatment, however.
Many instances in which a cat is reported to attack a person or other cat for no reason turn out to be cases of redirected aggression i.e. the cat, aroused to aggression by one stimulus, attacks another irrelevant person or cat. It does so because the original stimulus is no longer present or because it cannot be attacked. In a study of cases of aggression redirected onto people, the commonest arousing stimulus was the sight of another cat. The owner might be attacked when he approached his cat while it watched another cat through a window or if he tried to intervene in a fight between two cats. In four cases the arousing stimulus was a highpitched noise and, in four other cases, attacks were due to the arrival of a visitor to the house. The state of arousal which gives rise to a cat's redirected aggression may persist for some time after the disappearance of the arousing stimulus (for 30 minutes or more).
Several factors may further complicate the clinical picture. Redirected aggression may become classically conditioned to the victim. It may then be elicited repeatedly by the presence of the victim and in the absence of any arousing stimulus. If a cat is the victim, it may, in turn, develop a fear of the attacking cat and become defensively aggressive towards it. If the victim is the owner or other person, he or she may retaliate so strongly that the attacking cat develops a fear of him and becomes defensively aggressive towards him.
To treat this type of aggression, the arousing stimulus must be identified so that, in some cases, it can be eliminated. For example, if the cat becomes aroused by the sight of other cats looking in at the window, it may be possible to prevent them from passing close to the window by blocking access; it may be possible to deter them from jumping on the window sill by putting unstable objects on it. Alternatively the resident cat might be prevented from seeing outdoors by screening part of the window. If the arousing stimulus cannot be removed, the cat should be systematically desensitized to it: for example, the cat might be habituated to the arrival and presence of visitors using an indoor pen. Secondary problems in the form of phobias or defensive aggression should also be treated.Even when the problem is successfully treated, the owner should be on the alert for a similar reaction to another arousing stimulus in the future. In this event, she should keep people and other cats away from the aggressive cat until it has calmed down. This may take some hours.
AGGRESSION DURING PETTING Some cats, while being petted or stroked, will suddenly attack their owners, usually biting a hand or a wrist. Because the attack is not anticipated, often at a time when the owner is relaxing with the cat, he may feel shocked and upset out of proportion to the degree of injury inflicted.
For most cats, there isa limit to the amount of physical contact that they will tolerate in the form of being hugged, picked up, or petted. When the limits of this tolerance are reached, the cat usually reacts by attempting to escape, but occasionally reacts with aggression. Certain types of handling elicit such defensive aggression more quickly than others, for example tickling the abdomen or chest, especially if the cat is upside down. Such handling is best avoided in favor of stroking the head and back of an upright cat. Owners should also be encouraged to find other ways of interacting with their cats, for example, by playing with them. Most show some warning signs of impending attack, typically by restlessness or tail twitching. An owner who has been surprised by these attacks may be able to avoid them by detecting these signs if he is alerted to them. Ideally, however, he should always stop petting the cat before this point is reached so that it may then be possible to systematically desensitize it to the aspects of petting which it finds threatening and gradually raise its, threshold of tolerance. For cats with particularly low thresholds of aggression when petted, it is advisable to cease all attempts to pick them up. Instead they should be to accustomed to being touched while feeding, standing on a firm surface such as a table. The cat can then be stroked along the back and up the tail, if this is raised in greeting. It can then be gently and slowly lifted to the floor once it has finished eating. Eventually it should come to tolerate being lifted and held off the ground, and then being cradled in an upright position while the stroking continues.
IDIOPATHIC (MOTIVELESS) AGGRESSION
Occasionally a cat will mount a severe attack on its owners for no identifiable reason. However, the veterinarian should be reluctant to accept at face value an owner's account of motiveless aggression. Before diagnosing it as such, he should look for an environmental cause or trigger. Many cases of seemingly unpredictable aggression are, in reality, cases of defensive or redirected aggression. He should also, of course, investigate possible physical pathology. However, where aggression is a symptom of physical disorders (e.g. neurological or endocrinological conditions, idiosyncratic dietary intolerance), additional signs will usually be evident.
The lack of opportunity to engage in much play or any real predatory behaviour may so increase the motivation for this type of activity that a minimal stimulus will trigger it. In such cases, it is worth trying to reduce the aggression by enriching the indoor environment through frequent provision of novel objects and increased opportunity for play.