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Feline Social Structure & Aggression

July 2019





Cats have excellent peripheral vision and are extremely good at perceiving movement.  They are capable of some limited short-range binocular vision but, in general, don’t see too well close up.  Because of the wide dilation of their pupils, reflecting tapetum, and high density of rods in the retina, they have excellent night vision.  They also have cones (as do all mammals) and, therefore, have color vision.  They see best at the blue/green end of the visible light spec­trum.  Vision is a primary sense in a cat and is used in communication.  They are able to inter­pret different facial expressions, tail position, and body posture of other cats and, thus, to pick up on their affect. 




Cats can hear frequencies in the ultra-sound range and use this hearing range to detect itiner­ant kittens and small prey animals.  There are a number of sounds used in auditory communica­tion.  These are generally divided into two categories, the so-called pure sounds and the complex calls.

Pure sounds include:

  • murmur

  • purr

  • growl

  • squeak

  • shriek

  • hiss

  • spit


Complex calls include:

  • mew

  • moan

  • meow




This sense is much more important to cats than was formerly thought and maybe as important as vision.  Cats investigate odors several hundred times per hour and are as avid in this respect as dogs.  Areas of communication in which olfaction plays a role are:


  • scent marking with facial pheromones

  • scent marking with urine

  • fecal marking

  • anal gland secretions

  • clawing/scratching

  • gape response (c.f. vomeronasal organ)


Behavior problems related to olfaction include house soiling and furniture scratching. 







Social Behavior


Cats are generally solitary animals that only come together during courtship and mating or in the situation of a mother with kittens.  That said, it is quite possible for cats to develop strong bonds with each other and people.  The full complexity of feline social life is still not properly understood.  For example, it is not really understood why neighborhood cats gather together on opposite sides of an alley and sit there looking at each other.  Distances are very important to cats.  Distances that have been defined include:  personal space (within a very small radius or touching), social space (a distance inside which social exchanges are permitted, though per­sonal space may not necessarily be violated), territory (that area that the cat actively defends), and home range (that area that the cat traverses in the course of its outside excursions).  Home ranges are much larger for males (620 hectares) than for females (170 hectares) and are also less for neutered animals versus intact animals.


If two outside-living cats meet on one or other cat's territory, a social confrontation will ensue.  The aggressor will approach, walking on tiptoe with its tail lashing, making direct eye contact with the usurper.  Its head may be moving slowly from side to side as it approaches the other cat.  The approached cat may try to intimidate its adversary by hissing, spitting, and hunkering down whilst arching its back and pilo-erecting.  Most often the more subordinate cat will defer and run away without physical contact, however, sometimes the aggressor jumps at the usurper and a wrestling, biting match ensues. 

Social Structure of Cats:


Although I've already alluded to the solitary nature of cats, the fact is that they can exist in gen­uine social structures depending on the availability of food resources.  Japanese dockyard cats and British farm cats provided the first examples of community living in cats.  The community breaks down into smaller living groups comprised of two to seven females per group.  The males tend to wander far and wide, often visiting various groups in hopes of finding a receptive mating partner or for some other social reason.  The reason why social structure was not ap­preciated before so many years is that communication between the cats is often very subtle, taking the form of occasional touching of noses or flank glances.  Relationships between fe­males in a group are amicable, and they develop preferred associates while other cats they may actively avoid.  A group of female cats living together will repel borders against visiting females and young males and will positively attack adult males straying into the central area.  The rea­son for this is that adult males frequently kill kittens that they have not sired.  The true test of communal cooperation between individuals in breeding nests is the observation of “aunting”, cross-suckling, and cooperative hunting.  In the domestic situation, a despotic hierarchy some­times forms with one dominant leader and all the other cats subordinate, perhaps operating at an equal level through time sharing and other compromised gestures.  Some household com­munities contain a pariah cat that other cats pick on.  In nature, the pariah cat would be driven away or killed.  Very often, close bonds form between cats in household communities.  These bonds are most likely between relatives (e.g., mother and daughter).


Cat Personalities:


Like people, cats have different personalities.  Scientifically, these are categorized as either:


  • Alert:How active and curious is the cat?

  • Sociable:How amenable is the cat to interactions with other cats and people?

  • Equable:How even-tempered is the cat?


A cat that is very alert, sociable, and equable might be something like the classical Maine Coon.  A cat with a low score on alertness, sociability, and equability would be a real problem cat to have in a home, especially with other cats. 



Aggression is the number two feline behavior problem reported to behaviorists, second only to inappropriate elimination.  As with canine aggression, there are several different types, and the treatment depends on what is causing the aggression.  Aggression in cats (as in other animals) has been variously classified, although a system, analogous to that used in dogs, permits some comparisons to be made.  Therefore, classification of aggression into dominance-related, fear, or redirected aggression, etc. is quite reasonable.  An alternative classification, which is helpful when it comes to planning pharmacologic treatment, is the so-called Reis classification, in which aggression is considered as two main types:  a) Affective (offensive or defensive) and b) Predatory aggression.  All types of aggression where emotions are evident and there is associ­ated autonomic activation fall into the affective category, whereas predatory aggression is non-affective and sometimes referred to as the “quiet biting attack” type of aggression.


Dominance Aggression (Status-related Aggression, Alpha Cat Syndrome):


In the past, people have not really regarded cats as evidencing dominance aggression.  This is because cats do not have dominance hierarchies like dogs but are thought of more as an anti-social, solitary species.  Lately, this concept of cat society has been changing, and it is now known that cats will live in large dynamic groups with a loose social structure as long as there is an abundant food supply.  Two social structures have been described—one being a sort of des­potic hierarchy with one dominant leader and everybody else equal second in command (with occasional pariah cats) and the other being far more dynamic and interactive.  This latter hier­archy involves dominant actions by leader cats to assert their position, time sharing, and some prioritization.  Also, within the social group there are preferred associates and cats who actively avoid each other.  The whole social dynamic is similar to what occurs in humans, where group leadership may not initially be apparent. 


As it turns out, cats do have the same sorts of requirements as dogs and more dominant ones will protect food, objects, or territory and will repel unwanted gestures made towards them, reacting in a hostile way to admonishments or punishments.  Cats of this disposition may be less common than the equivalent type of dog, but they do seem to occur.  In the past, there was a type of aggression in cats, known as “petting-induced aggression,” which was reported to occur between cats and their owners.  The very orientation of this aggression is suggestive of dominance, and it has parallels in the canine world.  Cats that exhibit this type of aggression may show other signs of pushiness, too, such as insisting on being fed, waking the owner up in the morning, preventing the owner from resting in a chair, or meowing excessively for attention. 


Key Points:


  • Dominant cats have a pushy nature

  • Petting-induced aggression may be the presenting sign

  • First appears in kittenhood but persists throughout life

  • Affected cats may resist grooming, nail clipping, and discipline

  • Affected cats may be possessive/protective of food and toys

  • Owners are often kindly individuals who have “spoiled” their cat


Treatment for Owner-Directed “Dominance” Aggression:


1) Train the cat to perform “tricks”, e.g., to sit to receive food or assume a certain position.This can be accomplished quite easily by “click and treat training”.For information on this training method, a video is available by Karen Pryor (it can be purchased from 1-800-47CLICK).

2) Train the cat to perform one new “trick” per month.

3) Use the training acquired as above to insist on certain behavior prior to the cat receiving food or attention from the owner (e.g., train the cat to sit to receive food or petting).

4) Exercise the cat daily with moving toys (e.g., cat dancer, laser mouse, objects on a string).At least twenty minutes of playing per day will help the cat blow off steam and reduce its level of aggression.

5) If the owner is really intimidated by the cat, a water pistol, SSScat, or an air horn can be used as self-defense.

6) If aggression occurs during petting:

  • The owners should stand and let the cat fall to the ground.

  • For severe cases, suggest that cats do not need to be petted.

  • With systematic desensitization and counter-conditioning, these cats can be taught to accept petting.Start petting the cat at the level of the shoulder and reward with a small food treat.Over a period of weeks the owner should expect to pet the cat more and more for the treat.


Fear Aggression:


Like dogs, cats can become fearful of people or other animals and under these circumstances may choose to slink away and hide.  However, some cats are more proactive in dealing with their fears and will attack when frightened.  The concept here is that a good offense offers the best defense.  Fear aggressive cats are more likely to attack when cornered and unable to escape. 


Important facts about fear aggression:


  • Usually acquired, although there may be genetic influences.

  • Cats have been shown to inherit about 50% of their disposition from their sires.Inappropri­ate experiences in an early period of learning are particularly important when it comes to generating fear-based conditions.The critical period of development in cats is from 2 until 7 weeks of age.Adverse experiences, particularly towards the end of this period (and to some extent beyond), will have permanent adverse effects.Cats that have not been socialized to people before 7 weeks rarely become fully accepting of people’s company (especially feral cats).

  • Fearful cats display typical signs of fear including dilated pupils, flattening of the ears, open mouth threats, hissing, batting with paws, piloerection (especially bushy tail). This is called “feline affective defense response”.

  • Cats that have been exposed to a fear-inducing stimulus and have become riled can remain in that state for several hours and can be dangerous to handle.


Treatment for Fear Aggression to People:


As with all other fears, the essence of behavioral treatment is systematic desensitization with counter-conditioning.  The cat should be exposed gradually to the fearful stimulus while it is being engaged in some distracting/pleasant activity (e.g., receiving food treats).  If the cat is re­fractory to desensitization techniques, then pharmacological desensitization can be attempted.  Drugs that are useful for this purpose include the anti-anxiety drug, buspirone, and the seroto­nin re-uptake inhibitors, such as clomipramine and fluoxetine.  Beta-blockers (like propranolol) may also be helpful. 


Inter-Cat Aggression:


Cats show several different types of aggression toward other cats including:  fear aggression, territorial aggression, redirected aggression, non-recognition, and sexual.  We will discuss a few of the more important ones below.


1)  Territorial Aggression


Cats are solitary hunters, not pack animals by nature.  However, when food is plentiful, as it is in most of our homes, multiple cats can live harmoniously most of the time.  Nevertheless, even well-fed cats retain their instinct to define and defend a territory.  Outdoor cats mark their ter­ritory with urine, feces, and pheromones from scent glands.  Scent-marking serves to indicate the territory is occupied and reduces encounters between cats.  In close quarters, though, cats often negotiate subtle territorial rules including respecting distinct territories within a single room such as a couch or window perch.  Moreover, some feline housemates learn to “time share” favored locations, with one cat taking the front window in the morning and the other taking it over in the afternoon.  Unfortunately, anything that disturbs the “agreed upon” rules can lead to a confrontation, and what occasionally starts as a minor feline spat can erupt into a full-blown feud unless you can intervene.   It is important to keep in mind that when cats are confined indoors, they have little chance to avoid each other, and aggression is all too fre­quently the end result. 


Problems with territorial aggression are most common when a new cat is added to the house­hold.  If sudden introductions lead to aggression, this can set the stage for battles and does not bode well for the future.  The way to avoid this problem is to gradually introduce the cats to each other across a closed door.  A gradual introduction of a new cat to the household may take 2-3 weeks.


Territorial aggression between cats already living in the same household tends to develop grad­ually.  The more confident cat may begin to guard various resources and threaten its feline housemate over the slightest infraction.  Gradually the threats may progress to attacks and the victim may become progressively more frightened.  Depending on the “victim’s” temperament, it may choose to retaliate or hide, only making an appearance when the territorial cat is not around.  Occasionally, litter box problems may arise because the fearful cat is too afraid to leave its hiding place.  Additional problems of spraying/marking may occur because of the terri­torial stress.


2)  Redirected Aggression


Aggression intended for an outdoor intruder that is redirected onto a feline housemate can also severely damage the social bond between cats that have previously cohabited in harmony.  A typical scenario involves one cat resting by a window.  A second cat sees an intruder cat outside the window and rushes to attack it.  The first cat sees its housemate rushing toward it in an ag­gressive manner and becomes defensive.  The second cat redirects its attack on its housemate.  Theories as to why cats redirect aggression:


  • One theory is that one cat adopts an offensive strategy but being unable to attack the unwel­come visitor who is on the other side of a window turns around and attacks the cat next to it instead.

  • The second theory argues that one of the two cats becomes extremely frightened and as­sumes a defensive posture, pupils dilated, claws unsheathed, crouched body posture, ears flattened accompanied by hissing and swatting.The other cat observes this and believes it is about to be attacked and takes the offensive and a fight ensues.

  • Another scenario is when two cats are resting in the same vicinity when a frightening incident occurs such as an unusual and particularly loud noise.Both cats are startled and assume a defensive posture.When they see each other in this stance, they assume the other is ready to launch an attack.Each cat responds defensively, a fight erupts, and they remain fearful and aggressive toward each other afterwards.


In cases of redirected aggression, the cats should be separated immediately.  If this is done, and they are given several hours—if not overnight to cool off—they may be able to be reintroduced over a bowl of food.


3)  Non-Recognition Aggression


In other instances, feline housemates have a good relationship until something occurs, and they do not recognize one another.  For example, non-recognition can be triggered when one cat in the family returns from the veterinarian’s office or the groomer and smells and behaves differ­ently.  The cat that has been away may also release a scent from its anal sacs that signals fear and may cause the other cat to respond aggressively.  If a fight ensues, it can sometimes irrepa­rably damage the relationship.


4)  Sexual Aggression


Un-neutered male cats will fight.  Intermale aggression is reduced by about 90% by castration.  Neutered male cats are not “its”.  They are neutered males and will still show some residual male behavior.  One way this can be expressed is by aggression from a (usually) younger male cat toward an older female.  The aggression manifests as the male chasing the female and, when he catches her, biting her in the scruff of the neck (as in mating).  This behavior can some­times be eliminated by applying a male pheromone (androstenedione, Boarmate™) to the female’s rump daily.  Alternatively the male can be compelled to wear a large bell (audible warn­ing), and the female can be provided with many safe house retreats (hidey holes).  Medication can help, too, but is rarely necessary.


General Treatment for Inter-Cat Aggression:


1) Neuter all cats.


2) Keep nails trimmed as short as possible to lessen the chance of injury when cats are reintro­duced.


3) Set aside 10-15 minutes every day for each cat for interactive playtime.Encourage continu­ous aerobic play with laser pens, feather wands, or toys on strings to reduce anxiety and release energy.


4) Place bells on the cats.The bells must be loud and have different tones allowing them to be individually distinguished.This will also allow the cats to know each other’s whereabouts so there will be less chance for a surprise attack.


5) On a daily basis, rub each cat with a towel that has the other cat’s scent to familiarize each cat with the other’s scent.


6) If the cats end up in a fight, owners should not reach between them as they could be seri­ously injured.Instead, they should separate them with a blanket, broom, or whatever is handy. Alternatively, a loud noise could be made to startle them by dropping a pan or book. Cats become extremely agitated after an aggressive event and respond best to isola­tion until they become calm.Banish the aggressor to a less desirable area. The cats may need to be separated for as long as 12 hours.


7) Reintroduction:  Counterconditioning & Desensitization. We recommend two related tech­niques—systematic desensitization and counterconditioning.  Systematic desensitization accustoms a cat to the thing it fears.  Counterconditioning rewards the cat with something it needs or wants, such as food or attention, when it remains calm in the presence of the thing it fears.  Over time, these techniques work together to make a formerly stressful expe­rience pleasant and rewarding.  Time is the key word here.  This three-step program can take months and will require considerable persistence and patience on the owner’s part.  Throughout this process, be prepared to go back to the previous stage at any sign of hostile behavior, and then advance to the next stage again.  Neither cat should show anxiety or ag­gression during the reintroduction process.  If they do, go back to the distance where both cats were comfortable.  Look for signs of anxiety from the victim and aggression by the ag­gressor.  Signs of anxiety may include not finishing the food, eating quickly and leaving, avoiding eye contact, hiding, or trembling.Warning signs of impending aggression may in­clude staring, tail quivering, flattening of the ears, growling, hissing, stiff body posture, or piloerection.Banish the aggressor if this behavior is observed.


Reward the cats for ignoring each other.  If the aggressive cat averts its gaze, it should be re­warded.  If the cat that has been attacked makes direct eye contact with the aggressor, reward that response.  Do not give food treats or praise to either cat if they are showing fear or aggres­sion.  Only reward positive interactions between the cats.  Below is the three-step program in more detail.


Step I:  Separate the cats in 2 different environments within the house.  Water and litter boxes should be accessible to all cats at all times.  Confuse the cats’ tendency for territoriality by switching “environments” on a daily basis.  The daily exchange of scents maintains cat-to-cat familiarity in a non-threatening environment and prevents either cat from becoming territori­ally protective of a particular environment.


Step II:  Feed the cats simultaneously on either side of a barrier (e.g., closed door) so they can hear and smell each other while they are eating.  Once they are comfortable eating in each other’s proximity across the door, crack it open 1-2 inches and secure it.  This allows the cats limited visual access to each another.  If all is well, the cats can be allowed full visual access across a properly secured fly screen.  Both cats must be comfortable across the fly screen parti­tion before proceeding to the next step.


Step III:  Reintroduce the cats in the same room.  Initially, the cat should be restrained on har­nesses or in carriers.  Position them on opposite sides of the same room for 10-15 minutes as long as they remain calm.  Feed them, give them treats, attention, and play with them to make the excursion an enjoyable experience.  Bring them closer and extend their time together if there are no exacerbations of aggression.  The goal is to have them eating side by side and ig­noring each other in the same room.  Once they are peacefully eating side-by-side on harnesses or in their carriers, the next step is to release the more passive cat from the harness or carrier.  If all goes well, release the more aggressive cat during the next feeding.  If no signs of trouble are observed when one of the cats is free, the next step is that both cats are released simulta­neously.  Leave them alone together for increasing amounts of time.  Once they are allowed to be together for longer periods of time, the owner should continue to praise them or provide treats whenever they are seen together. 


NOTE:  If at any time there is a “meltdown”, the cats should be returned to an earlier phase of the reintroduction program with which they were comfortable. 


The process is tedious, and it may take several months to achieve acceptable results.  The rein­troduction process cannot be rushed and must proceed at whatever speed the cats’ behavior permits.  Sometimes resolution of this problem eludes even the most well-informed and patient owners, and the only recourse is to place one of the cats, usually the aggressor, in a new home.


Other Types of Affective Aggression:


There are several types of aggression that occur in cats, including pain-induced aggression, ma­ternal aggression, and pathological aggression.  Pain-induced aggression occurs when a cat is injured (e.g., someone steps on its tail, and it turns around and attacks).  Maternal aggression occurs when a cat is protecting its kittens (a bizarre antithesis of maternal protective aggression is infanticide).  Pathological aggression—e.g., in hyperthyroidism or seizures—will be dealt with in another section of these lectures/notes.



Predatory Aggression:


This is a normal behavior of cats.  Usually small rodents or birds are the targets of this aggres­sion, much to most owners’ and wildlife aficionados’ horror.  Keeping cats indoors usually thwarts this behavior but leaves cats needing some other predatory outlet.  In this instance, predatory aggression is directed toward other moving things, including owners’ feet, or can be expressed as a vacuum behavior (at nothing).  Predatory behavior toward an owner’s feet or hands is especially common in single kittens that do not have a playmate on whom to vent their pent-up predatory energies.  In such cases, getting another cat (preferably kitten) for the cat takes the heat off the owner and often defuses the situation.  Otherwise, owners’ only recourse is to try to discharge their cat’s predatory drive onto moving toys or other objects.

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