Aggression in Cats—And What To Do About It

Aggression in cats is one of the most complicated behaviors to understand, because it can mean the cat feels the need to defend itself or it’s just scared and putting up a front. Reasons range from obvious things like a new kitty, to more complex situations like they’re upset about something that happened hours beforehand. While it’s impossible to break down every circumstance, I’m going to share what to look for in body language first, and then we’ll review the different types of aggression. I hope this helps you better understand your cat. 🙏

Understanding Body Language

With body language, context plays a big role, as well as knowing your cat and their tendencies. Some very small differences can explain if your cat is on the offensive or defensive. The most important thing is to be very aware of your cat’s body position and the signals they’re giving you.

The best thing to do when you know a cat is getting aggressive is to leave them alone and let them calm down. If you try to touch them, you could get injured. Reassuring them also does little to comfort them or halt the aggression. And whatever you do, please, DO NOT punish them.

Cats do not understand our forms of punishment, and you’ll likely make them more aggressive, scared, or even confused. The body language outlined below is from the ASPCA.

Offensive Aggression

A cat showing offensive aggression wants to make itself look bigger and intimidating to their opponent.

Vocalization

• Growling
• Howling

Body Position

• Facing opponent and might approach
• Upright, but sometimes, back half is upright and face is near the ground
• Legs straight and stiff

Eyes

• Constricted pupils
• Direct stare

Ears

• Pointing up (not backward)
• Backs slightly forward

Fur

• Sticking straight up, like Halloween kitty

Tail

• Stiff and low
• Fur is sometimes poofed like mentioned above

Defensive Aggression

A cat showing defensive aggression believes it’s threatened and it can’t escape, so it tries to make itself appear smaller.

Vocalization

• Open mouth hissing or spitting

Body Position

• Crouching
• Head tucked
• Turned sideways

Paws

• Deliver strikes with front paws (claws out)

Eyes

• Pupils dilated (partially or fully)

Ears

• Flattened sideways or backward

Fur

• Sticking straight up, like Halloween kitty

Tail

• Curved around body and tucked

Whiskers

• Fearful cat - Panned out and forward
• Anxious cat - Retracted

Overt Aggression (Offensive or Defensive)

Overt aggression is when a cat displays outward and confrontational acts. 

Vocalization

• Growling and shrieking

Body Position

• Rolling onto side or back and exposing claws and teeth (prepared to fight)
• Fighting

Mouth

• Biting

Paws

• Scratching
• Swatting
• Striking
• Grabbing hand to try and bite it

Play Aggression

The most common type of aggression a cat owner will see is play aggression, which is usually caused by improper socialization. Kittens wrestle and play with their littermates, and that’s how they learn how to “play bite” and to put their nails away.

A singleton (kitten without siblings) or a kitten that was taken from it’s littermates too early may never fully understand the proper way to play. Additionally, kittens and cats with some sort of impairment, like an amputated leg, vision issues, or partial toe amputation (declaw) may also be overly aggressive during play.

Signs your cat displays play aggression includes everything they do when playing and hunting: attacking, swatting, pouncing, biting, scratching, and ambushing. Your best way to stop it is to try to distract the cat before they act, like with a wand toy or laser which will distract them.

You can also try using some sort of distracting noise that snaps your cat out of it, like a specific sound on your phone or even a can of compressed air. If the behavior seems tied to certain areas (like furniture they hide under before they pounce), eliminate the cat’s access to that spot.

Avoid negative interactions, which your cat will likely interpret as you playing with them aggressively, making the issue worse.

Lastly, always use proper toys. If you constantly use your hands to wrestle with your cat, replace that activity with giving them a kicker they can hold on to, rabbit foot, and safely bite.

Fear Aggression

Cats displaying fear aggression do not outwardly attack. They only attack if approached. The cat could be afraid of a person, animal, or even a sound, and the more scared they are, the more pronounced the aggression symptoms will be.

An important thing to keep in mind about this sort of aggression is that the cat’s perceiving whatever their trigger is as a threat – the “threat” may not even be a real threat to them, but if the cat thinks the vacuum is a threat to it’s safety, it will act accordingly.

You can work with a cat to get over being afraid of people and other animals by going slow and steady, as well as using positive reinforcements with treats and playtime. Ask the person the cat’s afraid of to give them treats or even sit on the floor with them for a little. Being closer to their level is less intimidating. 

Improving their fear around objects or sounds is much more difficult, because an object or sound can’t interact with the cat. The cat may be too scared to eat treats around the vacuum or while a fire engine is driving by. In any case, if a cat is extremely fearful, let them cool down before you attempt to touch them.

Remember that they are going to be defensive and feel the need to protect themselves. While we know the situation doesn’t require fight or flight, the cat doesn’t know that, and will likely not recognize you if you try to interfere (which could result in injury).

Petting-Induced Aggression

Although many people experience petting-induced aggression with their cats, it’s not completely understood. Behaviorists’ best guess is that repeated petting overstimulates, excites, or arouses cats. It’s also possible that while the petting feels good initially, perhaps it gets annoying, and the aggression is a cat’s way of telling a person to stop (since they can’t say, “Stop!”).

Signs your cat is getting overstimulated include whipping of the tail, dilated pupils, and ears pulled back, and are your warning to stop petting. Give the cat some time to chill before you try to interact again. Young children often miss these queues, so it’s extremely important to supervise them with cats or teach them to only pet the cat once or twice and then walk away.

The best way to avoid petting-induced aggression is to stop it before it starts. Try not to pet cats known to have this aggression for long periods of time.

Redirected Aggression

One of the most complicated types of aggression is redirected aggression. This occurs when a cat is excited but can’t respond directly to stimuli, so they turn to an animal or person who is close by or approaches them and takes out their aggression.

Common examples are when a cat sees a stray or bird outside, they hear loud noises, or they fight with another pet in the house. They won’t seek out someone to attack, so these attacks only happen if the cat is approached or someone is nearby. 

Why is this so complex? Because it can happen hours after the initial situation that upset the cat, so it seems unprovoked. This makes it extremely difficult to always know what upset the cat in the first place. 

Redirected aggression is also dangerous, because it puts you in the line of fire. Try to avoid breaking up cat fights, because there’s a high risk of you getting bit. 

Status-Induced Aggression

Some cats like to establish dominance against other pets, which is likely no shock to you – but you may be surprised to learn that some cats try to do this with people. The behavior is actually pretty easy to identify and includes blocking doorways from other pets and people and swatting when someone walks by.

The best way to combat this is to ignore. Just like with a person, if you give the cat attention, the cat will continue doing the behavior.

Territorial Aggression

A threat to a cat’s territory is something they take very personally, and a territory is different for every cat. Some cats may feel their house is their territory, while others may consider it a smaller space, like a certain room or even their spot on the couch.

In the wild, males have larger territories than females, but both can display territorial aggression in a home. While they can show it toward a person or dog, it’s more commonly against other cats. And just because they show this aggression against one cat, dog, or person, doesn’t mean they’ll show it toward all cats, dogs, and people in the home.

These situations tend to crop up when there’s a new pet or person in the home or when someone moves out or passes away. It can also happen if there are strays that mark near your home.

Although you can’t smell it, your cat can and considers it a direct threat. Lastly, if you have a kitten that has just reached sexual maturity, it can cause some issues in the home. Try to get that cat spayed or neutered as soon as possible to keep the peace.

Signs involve marking objects by rubbing on them and urine spraying (yes, spayed and neutered cats can spray if they feel their territory is threatened). Sometimes, a cat will slowly stalk their target, while others will aggressively attack. Hissing, swatting, and growling are just some things you can expect.

Things you can do to lessen territorial aggression is not to rush any interactions with new pets. Give each their own areas to start, as well as their own litter boxes and food bowls.

Over time, you can move them closer together, eventually allowing them to spend time in the same room together, while you supervise. You can also use baby gates to separate the pets, so they can see each other but still feel safe. If at any point in the process one or both regress, go back a step.

If there are stray cats outside, reach out to local nonprofits to see if they’ll help you TNR (trap neuter return) the cats. Fixed outdoor cats don’t mark as much and their urine smells different (less hormones), ultimately decreasing the odds of upsetting your indoor cats.

Maternal Aggression

Mothers are extremely protective over their kittens, especially newborns. Although it’s more common for them to display aggression toward other animals, they can display it toward humans as well. If you own a cat that has kittens or discover a friendly stray has had them, be very careful when approaching. Even if mama knows you, she could react negatively.

Pain-Induced and Irritable Aggression

Cats suffering from pain-induced or irritable aggression will have defensive body language. Even a sweet cat can be aggressive if they’re in pain and touched, especially if the area of their body that’s touched is the part that hurts.

The aggression can start as soon as the cat anticipates it’s going to be touched, and it can also last after the sore spots heal. Since cats have great memories around really great or really bad things, it’s possible they remember which areas previously had pain.

Make sure all cats with this type of aggression are examined for any underlying chronic problems, like arthritis or dental disease.

Idiopathic Aggression

Idiopathic aggression is very frustrating because it doesn’t have a clear cause. It’s likely these cats may have undiagnosed redirected aggression – remember, redirected aggression can appear hours after the incident that actually upset the cat. These cats will attack and bite repeatedly. If a cause can’t be determined and a cat is diagnosed with idiopathic aggression, it’s important to assess quality of life for the pet owners and the cat.

Work with Your Vet

Some cats even have a combination of different types of aggression. Work with your vet or a behaviorist to make behavior modifications and find other ways to relax your cat.

Popular medications for aggressive cats include SSRIs like Prozac, or even gabapentin, which is a nerve pain medication that can have a calming effect on cats.