Understanding Aggression in Cats

 Aggression in Cats

An Overview in Understanding Types of Aggression and Their Causes

The information presented below is not meant to replace proper veterinary care and is not intended to diagnose or treat any physical or behavioral issues. The enclosed information is gathered from both research and our own experiences in our animal sanctuary working with thousands of animals since 1991. This information is intended to be a starting point for you to understand your animals better and to search out the proper help for you and your animal friend.


Probably one of the most common questions we get at Spring Farm CARES is regarding cats that are acting aggressively. Sometimes cats are acting out in ways that people do not realize is a form of aggression. Many times you can change some simple things in their environment that can make a huge difference and, in other cases, it can be very difficult to find solutions. The first important question to ask yourself is: Am I willing to put some time and effort into solving this? Often this is a complex process and requires time and commitment. Many times you can make a difference simply by understanding what is happening with your cat and what is triggering his/her behavior. In this article, we explore the various types of aggression and ideas of what you can try to do with your cat to prevent or alleviate incidents. 

Let’s first explore how aggression expresses itself in cats as well as various types of aggression. If you see your cat in some of these examples, you may want to take a new look at his/her behavior and see if there is something you can do to help them stay out of situations that trigger them to be aggressive. The number one thing you can do for your cat is to avoid the situations that trigger the behavior. 

We frequently get calls from people saying, “My cat just went after one of my other cats and it was TOTALLY unprovoked. NOTHING caused it to happen.” Although some forms of aggression, such as physical/neurological problems, can seemingly cause aggression without any warning or provocation, it is much more likely that indeed something did trigger your cat but you are not aware of what it was. As you will see below, cats can react to a stimulus hours after they are triggered and to you it will look like absolutely nothing happened. But to your cat – something did happen and he/she is reacting to it. 

The first step is to start documenting the times your cat displays aggressive behavior. Again, we will discuss below what many of those behaviors are and what it looks like. You may even want to start a notebook where you write down what the behavior was and what was going on around your environment when it happened. Something that seems unimportant to you may indeed be exactly what triggers your cat. It is important to be extra observant as to what is going on. Are there other cats around at the time? Was there a lot of activity or noise in the house at the time? Did a stranger enter the environment? Is there a new cat in the house or even in the neighborhood who he sees out the window? 

If the aggression is between two of your cats, what were the two cats doing prior to the episode? Watch for signs of posturing between cats. Learn about the signals and body language between cats to better understand what is happening. 

This article is meant to be a starting point for you to better understand your cat and what is happening and to hopefully be able to make some changes that benefit both your cat and the peace in your household.

What Are Some of The Signs of Aggression?

Aggression between house cats can be subtle and oftentimes complex. It can be so subtle that you may not even really know what is going on or building up between your cats. It can be easy to miss at first. The aggressor cat postures and the other cat will try to make herself look smaller and may then run off to avoid the aggressor. Sometimes aggression can be related to physical size with larger cats picking on smaller, less active cats. It can also be attributed sometimes to cats who were not socialized well to other cats and simply do not know what to do in “social” situations. Aggression can also be accidentally paired with some unpleasant outside force (like a bad thunderstorm or fireworks or other loud sounds). Or, it can be as simple as the two personalities simply do not get along. In multi-cat households, the factors are even more magnified. Let’s face it, all of these factors can and often do affect humans the same way. If you think about it, look at how humans respond when they are suddenly placed in a group situation and forced to stay together. Some of you will get along well with everyone and some just will not be able to tolerate it and will begin acting out accordingly. It is no different for our cats. 

Sometimes cats also get bored and the “class clown” and “bully” personalities will start to amp up their antics simply to get a reaction. We often see this in our cat rooms where we will have the one cat who just has to be an imp and doesn’t rest until he can stir something up. That cat is also very adept at picking out the drama queen cat who he can get a rise out of simply by giving her a good stare down. If the drama queen cat responds accordingly and lets out a scream and runs off, then his behavior is reinforced by having gotten the response he had hoped for. It was not necessarily that he was trying to be mean. It was just that he was looking for something to do. Identifying how your cats are relating to one another on a daily basis may offer helpful insight into what is really going on with your cats. 

Types of Aggression

Fear or Defensive Aggression

Fear aggression occurs when a cat perceives a threat and feels trapped if he can’t escape from the cause of his fear. The more threatening the human, other cat, moving object, loud sound seems to her, the greater her reaction will be. Typical signs and body postures of defensive aggression include crouching, flattening the ears, tucking the tail, leaning away or rolling onto their side, and pupil dilation. And aggressive signals can include hissing, spitting, hair standing up, growling, swatting, biting, and scratching. The easiest way to deal with a cat in this situation is simply to avoid interacting with them until they can calm down. We often see very well-meaning people trying to help cats adjust to new situations (such as being adopted into a new home) by forcing the cats to interact with them. Pulling them out from under beds or chairs where they have found safe places to hide can result in a fear or defensive aggressive episode. It is important to let cats find their safe places and to go slowly to try to gain their trust. Think of how you feel in similar situations. All of us need places where we feel safe. And some of us take longer than others to adjust to change. Animals are no different.

We also see this as a common behavior issue when people are trying to get their cats into carriers. From the cat’s perspective, we are shoving them into a box with no escape and usually doing something with them (like a trip to the veterinarian or animal shelter) that elicits great fear for them. Often they respond aggressively out of fear. It is common for us to hear people say, “He bit me for no reason. I was only trying to get him in the carrier.” But, indeed, the carrier was the entire trigger for the cat’s fear which then escalated into feeling totally trapped and responding accordingly. These are situations where we humans can make things much easier for them simply by slowing down and thinking things through step by step to see where we can make it easier for the cat. 

Ideas for Dealing with Fear or Defensive Aggression:

The management of this problem involves, if possible, avoidance of fear eliciting situations. We can also minimize contact with cats who are fearful until they calm down and can regroup. Over a longer period of time, we can try to desensitize the cat to the object or situation causing fear. One such example is a cat that is terrified of the cat 

carrier could be worked with to make the carrier as easy as possible for them to deal with. For instance, make sure the carrier is big enough so that the cat doesn’t feel trapped. It should be big enough for them to comfortably turn around inside the carrier. You can leave the carrier out in the house with the door off and put a nice blanket or bed it in with some treats and let them explore the carrier on their own so that they associate it with good things. They may even learn that the carrier can be a safe place for them. But this cannot be done while the cat is already afraid and cannot be expected to work if you are trying it an hour before you leave for your veterinary appointment! 

It is important to identify the fear and then brainstorm as to how you can make it easier for your cat by breaking it down into tiny steps. Punishment will only serve to make the fear worse and thus the aggression worse. Rewarding positive behavior and tiny steps toward your goal will go far in helping your cat feel more safe and successful. 

Territorial Aggression

Territorial aggression is common to most species sharing our planet with us – humans included – and cats are no exception. Territorial behavior is common to both males and females and it is a fallacy that only males are territorial. Males may defend larger territories than females but both can be equally territorial. Cats usually display territorial aggression toward other cats but they also can do so towards dogs and humans. A cat can also be territorially aggressive toward some family members and not others and towards some cats and not others. In one of our on-site residences, there are five dogs living with seven cats and generally all of them get along. But one of the cats can become highly aggressive to just one of the dogs while hanging out with all of the other dogs without incident. In fact, that particular dog is the friendliest to all of the cats and is a favorite to every other cat except the one who will suddenly get aggressive with him. For whatever reason, that cat just doesn’t like that particular dog. So we do our best to avoid situations between them that could escalate into aggression from the cat.

Cats mark their turf by patrolling, chin rubbing and urine spraying. They also can stalk, chase and ambush a targeted intruder into their territory. They often will then display offensive body postures toward the intruder including hissing, swatting and growling. Some cats stalk their intruder with a slow and steady approach, while others immediately give chase. A cat’s perceived territory can vary greatly. It can be the entire house or just parts of it, such as a favorite room or even a favorite cat bed or chair. It can be the yard, the block, or for those truly ambitious cats it can be their entire neighborhood. Some cats take their patrolling very seriously. 

Some common situations that trigger territoriality are:

• A kitten in the household reaches sexual maturity. This is one we see a lot. People will say, “She always got along with the kitten and at first was even very maternal. Now suddenly, for no reason, she has started attacking the kitten.” The thing is that their roles in life change just like they do for us humans. A cute kitten is one thing, until it reaches maturity, and suddenly it is now seen by the other cats as another adult cat in the household competing for space, food, attention, and favorite sleeping places. 

• A new cat being introduced to the household.

• Major changes in the cat’s family or environment. Examples are moving, a person moving in or out of the house, family feuds/fights/arguments, a death in the family, a death of another family pet, etc. We have also seen behavior changes like this just from people getting new furniture or redecorating their home and significantly changing the space. Frequently the change may seem small to us but in the cat’s life they are big or complex. 

Ideas for Dealing with Territorial Aggression:

When introducing new cats to the household, even when it is a kitten, it is best to do the integration slowly. It is best to start the new cat out in one room with a closed door between the other cat(s) of the household and with their own litter box and food and water bowls. As the cats can smell each other through the door and get used 

to the sounds and routine of the household, you can then slowly proceed in moving forward with introductions. Some cats need more time than others to accept a new cat into their territory. 

If there is a move to a new home or apartment, or when combining households as two people move in together and each bring their own animals with them, it is best to again start out slowly and limit their space until they are used to their new space and the smells and sounds and routine in their new environment. 

Play Aggression

This is a most common form of aggression that can be accidentally and easily induced by the humans in the household without realizing what they are doing. Rough play is very common and natural among kittens and young cats less than two years of age. If you watch a litter of kittens play, you know how rough they can be with one another. However, when they direct this rough play at humans, despite their intentions to just be playing, it can cause injury to people. Play aggression is the most common type of aggressive behavior that cats direct towards their human family. And it can be one that we can probably help change the most just by altering what we do with our kittens and young cats.

Play aggression involves typical predatory and play behaviors. Let’s face it, it is funny to watch them wiggle and wiggle and pounce on things that they are stalking. It includes behaviors such as stalking, chasing, attacking, running, ambushing, pouncing, leaping, batting, swatting, fighting and biting. It is believed that through cats playing with each other they learn to inhibit their bites and to sheathe their claws when swatting. The degree to which cats learn to inhibit their rough play varies. Orphaned kittens have a much harder time learning this. It is very important that rough housing with kittens be limited, especially raising orphaned kittens. The orphaned kitten often lacks the social skills that would usually have been taught to them by their mothers and siblings as they mature. They can be more prone to play rough, simply because they don’t know any better and are just following their prey and play instincts. 

Other factors can contribute to play aggression as well such as boredom. Long hours spent alone without opportunity to play can lead them to be overzealous in their play when someone does come along. Enrichment for cats is a very important factor to a healthy emotional life. Having toys available and things that offer intellectual stimulation is very important. 

I’m sure we’ve all enjoyed a cat suddenly getting the “zoomies” as they tear around the house as if they are being chased by the devil. Many of them do this simply to relieve boredom. It’s fun. It’s exercise. And if they see it makes their human family members laugh they can also choose to do it all the more. It is one of the ways they connect with us. 

Ideas for Dealing with Play Aggression:

The best way to handle play aggression is to avoid playing aggressively with your cat. However, when the cat initiates the rough play and gets overzealous, physical punishment can have negative ramifications and can actually make the cat more aggressive. It is far better to walk away from a cat that is playing too rough. They get the message that rough play leads to no play, so if they want to play with us then they need to be more gentle. 

The kind of toys we use to play with our cats can also help avoid play aggression caused by us. It is helpful to play with toys that are at a distance, such as tossing cat toys or balls for your cat to chase, or fishing pole style toys where you can engage with your cat but at a distance from your hand and body. Providing climbing perches and scratching posts is very helpful for cats to play more instinctively in a way that makes them happy. 

If your cat obsesses more on playing with your hands, then try to discourage that behavior. You can even try treat balls – toys that they can batt around and that dispense treats to encourage your cat to play with an object rather than with you.

Petting Induced Aggression

In our experience, this is another very common form of aggression that is often misunderstood by people. We have had many wonderful cats returned to us with people telling us they are aggressive and biting family members when indeed the people are inducing this behavior without even realizing it. 

Some cats totally enjoy being petted, held, carried and hugged. Some just tolerate that behavior. And there are some that don’t like it at all. Petting induced aggression occurs when a cat suddenly feels irritated by being petted, nips or lightly bites the person petting him, and then jumps up and runs off. It seems that what is happening for these cats is that the petting becomes annoying to them if it is repeated over and over. Repetitive petting can cause excitement, arousal, pain, and even static electricity in their fur. Imagine what it feels like when someone keeps stroking your back or your head over and over again in one spot. For many people, that quickly becomes uncomfortable and annoying and you abruptly need it to stop. It is no different for cats. What started out as feeling good suddenly changes and becomes unpleasant and he wants you to stop. Often times the cat actually gives a signal that he is uncomfortable. It is important to be aware of the signs so that when your cat does become uncomfortable or annoyed then you can simply stop petting them. 

Careful observation is always the key to understanding your cat’s communication signals. 

Warning signs include: 

• Quickly turning his head toward a person’s hand

• Twitching or flipping his tail

• Flattening her ears or rotating them forward and back

• Restlessness

• Dilating pupils

Another common problem we get called about is when cats get aggressive when being picked up and held or hugged. As mentioned above, some cats love this. But some do not. Animal Communicator Dawn Hayman has noted in many years of consultations with cats displaying this aggression that there is often one common factor. These cats feel very uncomfortable with heights especially when their feet are not touching something solid. They can literally panic as they feel they are going to be dropped or that they will fall. Holding these cats tighter and harder serves only to escalate their fear and aggression. For cats who have this issue, simply sit on the floor with them or have them on a surface where all four feet can touch something solid. Often, they will calm right down and relax. 

Ideas for Dealing with Petting Induced Aggression:

One of the first things, and often one of the hardest, in dealing with petting induced aggression is that it may be that the cat you are looking for to be on your lap snuggling may not be the cat who can give that to you. Again, not all cats are into snuggling and it varies from cat to cat what they find tolerable or desirable. 

Physically restraining your cat to get him to forcibly accept affection may serve only to make matters worse and escalate the aggression. Try different approaches such as letting your cat come to your lap without petting him. Sometimes they want to sit beside us but don’t like being touched. Sometimes they just like being petted a couple of times and that is enough for them. Watch their body signals and listen to what they need. It may be that over time they will enjoy the contact more. But they also may not ever like to be petted much. 

There are some simple fixes for this behavior. If your cat doesn’t like you petting him, then don’t pet him. If she doesn’t like you picking her up and carrying her around, then don’t pick her up and carry her around. You can start slowly by letting them approach you and you giving them a treat. Then work up to stroking them once and giving them a treat. You can work your way gradually up to more contact. But forcing them to do these things will simply make it worse. 

Redirected or Transfer Aggression

Redirected aggression is probably the most dangerous and often complex type of cat aggression because the bites are uninhibited and the attacks can be frightening and damaging. It also unfortunately is a very common form of aggression in cats. Redirected or transferred aggression happens when a cat is aggressively aroused and agitated by an animal or person he can’t get at. An example of this is a cat who sees a stray cat outside the window in his territory. Unable to get to the trigger of his agitation, he turns and lashes out at someone else. That could be a person, a dog, or another cat who is nearby or who suddenly walks into his vicinity. The aggression is transferred or redirected to the object he can get to. The problem is that there can be a considerable delay between the initial arousal and the redirected aggression, as long as hours even. This is why people often describe this aggression as coming out of nowhere or happening out of the blue. They weren’t even aware of the initial trigger – for example, that a stray cat walked by the window a half hour before – and so have no clue what initiated such aggression. A redirected attack occurs only if an agitated cat is approached or there is someone close by. The cat will not go looking for someone to attack. It is not premeditated but is a violent response. These attacks are not intentional or malicious. It is like a knee jerk reflex response, done automatically without any thought. Because of this, it is never a good idea to try to break up a cat fight or to approach an agitated cat showing defensive or offensive aggression behavior.

Some common triggers for redirected aggression are:

• Watching another cat through a door or window

• Watching or stalking birds, squirrels, or other prey animals

• Smelling another cat’s odor on a family member, a visitor or clothing

• Coming indoors after getting outside if the cat usually is limited to living indoors

• Hearing high-pitched noises

• Being frightened or harassed by a dog

• Having a person intervene in a cat fight

• Being in an animal shelter, surrounded by the sight, smell and sound of other cats

• Roaming cats in the neighborhood enter a cat’s territory

• Loud sounds and commotion on a television

You can see that aggressive behavior caused by when a cat is stressed is very hard to read and assess the cat’s temperament. They may indeed just be overstimulated and showing transfer aggression rather than being a “nasty” cat. We had such an example in our facility with a wonderful cat named Monique who we adopted out to a wonderful home. Months later, we were called by a very hysterical adopter that Monique and just brutally attacked her and we had to come get her out of her house right away. When our staff arrived, they were horrified to see the human with horrific scratches down her arms and legs. She had been bleeding all over and had wrapped her wounds up. It indeed had been a severe attack. We had not seen any such behavior from Monique before! The woman told us that it came on totally unprovoked and out of the blue. Monique had been standing by her patio door looking outside. She seemed agitated and the woman stepped up to move her away from the door. And Monique literally sprang at her with claws flying. When brought back to our facility, everyone was afraid of Monique. The question was whether we’d need to euthanize her or not. We saw what she had done. But we didn’t understand what had happened.

At the time, we didn’t realize that this was a classic case of Redirected aggression. After several days, Monique was still acting like her normal wonderful friendly self with us. We wondered, did she have some sort of brain tumor? Was she mentally losing it? What would cause her to snap like that? And then we spoke with her adopter again. She had told us that for days a stray cat had been coming up through the yard and even had walked up to the window and looked in at Monique and that Monique got very upset. The woman was afraid that would happen again which is why she tried to move her. There we had it. Redirected aggression. Indeed, there was a known trigger, but it was misunderstood and unrecognized. Monique lived many wonderful years with us and never once showed any 

kind of aggression again. If we had rushed to judgment, a wonderful cat could have lost her life due to humans not understanding what had happened to her. 

Pain-Induced and Irritable Aggression

Pain induced and irritable aggression are triggered by pain, frustration or deprivation, and they can be directed toward people, animals, and objects. Any animal, including humans, can get aggressive when they are in pain. Even well-socialized, normally friendly cats can lash out when they are hurt or in pain or when they anticipate when someone is trying to touch a painful part of their body. Cats showing aggression should always be checked out by a veterinarian to rule out pain as a cause of the aggression. Cats will often hide illnesses and injuries as an instinctual survival trait. But they can have illnesses such as dental disease or ear issues that can cause them tremendous pain and anxiety. When people are touching painful areas, the cat may get aggressive just out of protecting itself. 

It is also good to note that using painful punishment to address cat behaviors is not only ineffective but can also trigger pain-induced aggression and worsen other types of aggression, like fear and territorial aggression. We have had instances of people using water spray bottles at cats who are being territorial only to have that cat then turn on another cat in the house. Was it unprovoked? No, the human actually triggered a redirect aggression and the cat simply reacted.

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