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Sudden unprovoked aggression in cats
Sudden unprovoked aggression in cats | Photo by Dids from Pexels

Why on earth would your cat bite you?

I can only imagine your shock and disbelief as you scour the internet for a good explanation of the sudden unprovoked aggression in an otherwise calm cat.

Cats are known to be calm and poise with an attitude that seems to say ‘I don’t need you that much’, which is why getting bit by one is similar to seeing a lightning strike on a sunny day.

However, as unpredictable as unprovoked aggression in cats may seem, they don’t get aggressive out of nowhere – and trust me, it’s more common than you think. 

Though cat behaviors can sometimes be hard to read, I’ll show you how to deal with cats that display sudden unprovoked aggression to prevent future episodes.

What is cat aggression?

Aggression is a common feline behavior that is used to dominate or intimidate.

While an aggressive cat seems to be less serious than an aggressive dog – probably because cats are smaller and don’t pursue their victims – they are still dangerous and at risk of being abandoned outside by a frustrated owner or surrendered to a shelter. 

Having an aggressive cat at home is a real danger to the family, visitors, and other pets. 

Why so? 

Cats have five potential weapons (all four clawed paws and their teeth) whereas a dog’s sole weapon is its mouth. An aggressive cat will not only bite, it’ll inflict severe painful lacerations that can easily get infected. 

You can also catch cat scratch fever, a mildly infectious disease that can cause flu-like symptoms. Rarely would you see fatalities in catfights, however, the lacerations inflicted can get infected, leading to expensive veterinarian treatments.  

So, why is your cat suddenly aggressive to you?

Common reasons cats display sudden aggressive behaviors


We both know cats are solitary critters, however, they are sociable and can form strong bonds with the people they love, they just aren’t clingy – even to their favorite humans.

A cat can become aggressive and instinctively lash out to protect itself if it feels threatened or stressed. 

Some of the most common causes of stress and fear in a cat are 

  • Sudden movements (especially when you have too many people at home).
  • The presence of a new pet in the home.
  • Too many pets in the home.
  • Loud noises.
  • Unfair punishment or harsh treatment.
  • Sneaking up on them.
  • A disruption to their routine, or lack of a routine.
  • Riding in a carrier or a vehicle.
  • Lack of resources (cat food, clean water, and litter box, toys, scratching post).

For rescued cats, aggressive behaviors can be triggered when they remember a bad experience they had as a stray on the street, or while living in a shelter.

Sometimes, you may not fully understand the cause of the fear or stress, however, it’s good to know that cats may become aggressive if they feel they don’t have a way to quickly escape from a scary situation. 

For instance, if a cat gets startled by a sudden movement or loud noise, it might attack the closest pet or person.

Painful medical condition.

When a usually calm cat suddenly attacks you, the owner out of nowhere, then you should schedule a visit to the veterinarian. This is because cats and dogs – to an extent – are stoic and will try to bear the pains of an injury or sickness. 

A cat displaying aggressive behaviors could be trying to protect an injury or a tender area from being disturbed. Many times, they think the cause of the pain they feel is external and will lash out at any pet or human close by when they feel the pain. 

Some common sources of pain that can lead to sudden aggressive behaviors in cats include abdominal pain, soft tissue injuries or infections, dental disease, or arthritis.

Neurological issues, loss of smell, sight or hearing, and cognitive decline can make a cat lash out in sudden bouts of aggression.  

A visit to the vet will rule out or treat underlying medical conditions that might be causing aggressive tendencies.  

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Territorial Issues.

Cats are territorial animals and they’re not afraid to use aggression to prevent access to their territory. While this sort of aggression is common in a home with multiple cats, a cat can also have territorial spats with humans or dogs. 

You know the interesting thing about cat territorial issues? 

As their favorite human, you are part of the cat’s territory. If you are the cat’s favorite, it might attack you out of jealousy when you give attention to a different pet or when it picks up the smell of another animal on you. 

If your cat becomes aggressive when you or other pets try to enter certain areas or lurks around you when an unfamiliar guest visits, then you’re likely looking at territorialism. 

You might be able to relieve territorial aggression by adding extra litter boxes, cat scratching posts, and food and water stations, so the cats don’t have to share things they consider to be territorial properties.  Feliway MultiCat can be used to calm this type of aggression.

Sexual aggression

Hormones may cause cats to display aggressive behaviors, especially cats that haven’t been spayed or neutered. However, the behavior is predominant in male cats since they are wired to compete with other mature males for a fertile female on heat. 

If you see two males fighting for superiority, do not attempt to separate them because you will likely come away with injuries or become the target of their aggression. 

Some male cats may mount a person’s ankle or arm, grab the skin with their teeth and start humping. Trying to dislodge the cat at this point will result in increased aggressive behavior. This sort of sexual aggression does minimal damage to the female cat’s skin since their thick scruff protects them from the male’s nape-bite.  

“That’s enough petting for today” aggression.

Of all the reasons why a cat suddenly becomes aggressive towards the owner, this one is the most confusing. This happens when your calm cat that seemed to be enjoying the movement of your fingers in its fur suddenly turns on you, and tries to shred your skin with its teeth and claws, then jumps off and walks away – majestically. 

This is a classic case of petting aggression, that’ll leave you wondering “what just happened?”

Not all cats enjoy being held, petted, hugged, or carried. Even those that do only tolerate a certain amount of affection from their owner, any more affection after this point becomes irritating. 

So, how do you tell that your cat has had enough? 

When a cat is tired or satisfied with the play session, it will display some signs for you to stop. By carefully observing its body gestures you can tell exactly when to end the play session and let it go or just sit there on your laps. You’ll usually see warning signs, such as:

  • Quickly turning his head towards a person’s hand. 
  • Flattening his ears or rotating them forward and back.
  • Dilating pupils.
  • Growling and tail thumping
  • Twitching or flipping his tail.
  • stiffening of the body.
  • Restlessness

When you notice or, in most cases, fail to notice these signs but keep on petting the cat, its last resort to get you to stop is lashing out or the unprovoked aggression that seems to come out of nowhere.  

Frustration/Redirected Aggression.

Redirected aggression is when a cat becomes super irritated, excited, or stressed by a trigger that is beyond its reach, so it turns around and attacks a human or pet close by to release the pent up energy. 

A common scenario is when an indoor cat cannot get to defend its territory or attack the cat, bird, squirrel, or lizard it sees on the other side of the window. It’s also possible that your cat caught a scent or heard a noise that triggered unpleasant memories. Maybe it caught the scent of another animal on you or a visitor, or another cat came back smelling like the vet’s office.  

Predatory aggression.

Cats are predators! Though they behave docile and friendly most of the time, predatory behaviors come naturally to them.

Many experts don’t classify predatory behaviors as aggression – I agree with them. This is because the purpose of such highly motivated behavior is to obtain food whereas other types of aggressive behaviors are used in response to conflict. 

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Cats are superb at hunting prey. They locate prey with their acute vision and sensitivity to high-pitched sound. They hunt birds, rodents, insects, reptiles, and young rabbits. 

When a cat detects a prey, its predatory sequence of behaviors kicks in, starting with silent stalking. It then monitors the prey until the timing is perfect to strike. During this time, you’ll notice the cat’s rear end wobbling from side to side or the tail twitching. Then finally, the cat will sprint forward and deliver a fatal bite to the prey.  

If your cat goes through this sequence of action when it spots a prey on the other side of the window, but cannot get to the prey, it’ll turn around and attack the closest human or pet. 


Protecting one’s offspring from potential danger is a behavior that is instinctive to most animals. What we humans perceive as sudden unprovoked aggression, especially in mother cats, is simply the cat’s maternal behavior aimed at protecting her kittens from people or animals that she sees as a threat. 

While it is often directed at other cats or dogs, humans can also find themselves at the receiving end of a mother cat’s rage.

This is why it’s a good idea to avoid handling kittens during the first few days of their lives, except the mother cat chooses you to be her offspring’s guardian while she’s attending to other cat duties. 


In cats, idiopathic aggression includes any type of aggressive behavior whose cause cannot be explained through a medical exam or by studying its behavior history.

Cats with idiopathic aggression can violently attack their owner without any provocation.

These cats are dangerous, especially around children, since they may repeatedly bite or scratch and remain in an aroused state for an extended period.   

What are the warning signs of aggression?

Threats and aggressive behaviors in cats can either be defensive or offensive. Irrespective of the cause of the aggression, it’s helpful to know that an attack is about to happen so you can keep your skin intact.

An aggressive cat that’s on the offensive tries to look more intimidating by making itself look bigger, while an aggressive cat that is defensive takes a self-protective posture that makes it look smaller than it actually is. 

Here are some typical body postures you’ll notice in an aggressive cat. To prevent injury, do not attempt to punish, touch, or reassure a cat displaying this body language.  

Cat offensive body language include:

  • Direct stare.
  • Might be yowling, howling or growling.
  • Upright ears, with the backs rotated slightly forward.
  • Rear legs are stiffened, with the head close to the floor and the rear end raised forming a slope from back to the head.
  • Constricted pupils.
  • Tail is stiff and lowered to the ground.
  • Hairs on the body becomes raised. 
  • A stiff, straight-legged upright stance.
  • Directly facing the opponent, possibly approaching it.

Cat defensive body language include:

  • Makes itself smaller by crouching.
  • Eyes wide open with pupils partially or fully dilated.
  • Hairs on the body becomes raised. 
  • Open-mouthed hissing or spitting.
  • Might deliver quick strikes with front paws, claws out.
  • Ears flattened sideways or backward on the head 
  • Facing the  opponent sideways, instead of directly, as if looking to escape.
  • Tail curved around the body and tucked in.
  • Head tucked in.
  • If the cat is fearful, whiskers might pan out and forward to assess the available space between itself and the danger. If it is anxious, its whiskers might be retracted.

Cat overt aggression, either offensive or defensive, includes:

  • Growling or shrieking.
  • Fighting.
  • Biting.
  • Striking, scratching, swatting with paws.
  • Rolls onto the side or back and exposes all weapons (claws and teeth) in preparation for an all-out attack.

What to do with an aggressive cat

aggressive cat about to attack
cat ready to attack

Find the source of aggressive behavior.

To resolve your cat’s sudden aggressive behaviors, you will need to identify the reason behind the aggression so you can better manage their behavior. Other than medical issues, most reasons that cause a cat to become aggressive are temporary and likely easier to manage.

For instance, when dealing with maternal or petting aggression, you just need to stay away from mama cat and let her do her thing, and stop petting your cat when its body language says “that’s enough.” 

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Interrupt the aggressive behavior.

It can be difficult to reel your cat in once its aggression takes off. The best way to stop aggression is to interrupt the behavior in the early stage.

Try distracting the cat by throwing a toy somewhere they can see, whistling, shaking a jar of marbles, or – gasps – placing the very effective and automatic cat laser light on the floor where they can see it.

Never attempt to interrupt aggressive behavior by picking the cat up, or offering cat treats, the latter only reinforces the behavior.  

Use calming diffusers and sprays.

There are lots of products available for calming an aggressive cat. They come in diffusers and sprays that contain pet-safe chemicals that mimic feline pheromones that cats can recognize.

What’s the best way to use these kinds of products?

Only use these diffusers and sprays when you are expecting a guest or notice your cat growling, yowling, or displaying any early warning signs of aggression.

Using diffusers and sprays works perfectly, especially if you notice your cat is suddenly aggressive to one person.

Feliway MultiCat provides a reassuring familiarity that makes your cat feel safe and secure. The results is a calm cat that is less anxious or scared.  

Provide alternative stimulation.

Dogs use aggression to relieve stress, and so do cats.

If your cat seems to be full of energy each time, you can help it get rid of some of that energy by adding climbing perches, fun and quality scratching posts, and spots where a cat that wants privacy can curl up.

A simple cat condo or a cat tree where they can perch on and scan the room will work wonders. 

Another option is to play with your cat. However, this should only be done when your cat is calm.

The fail-safe method to go about this is to let the cat approach you for play, not the other way round. End the play session as soon as your cat begins to act aggressively.

Stay away from a cat’s domain.

A cat will make sure other animals (and humans too) know that they are the boss once they’ve established their domain in a part of the house.

If you are adding a new cat to the family, or if one cat suddenly becomes aggressive to another after cohabiting for a long time, then you’ll have to separate their living, eating, and litter box areas. You may have to go as far as getting separate toys. 

Try behavior modification.

Behavior modification is conditioning that seeks to modify undesirable behaviors using positive or negative reinforcement.

For instance, if your cat reacts aggressively when touched, behavior modification can help you break that pattern by forming a positive association with petting by offering food or treats each time you pick up your pet – reduce the frequency when the behavior disappears.   

However, you need to work with a professional otherwise you could imprint your beloved cat with wrong behavioral patterns that might be difficult to unlearn. 

A qualified professional will look at your cat’s behavior history, develop a custom treatment plan for your cat, and coach you through its implementation.

Since a mishap can have detrimental effects, a good behaviorist will monitor your cat’s progress and alter the plan as required. If living with your cat poses a high risk, your pet may have to be rehomed or euthanized.  


No matter what the cause of the aggression may be, the bottom line on dealing with sudden unprovoked aggression in cats is to watch out for warning signs because there’s always one or two. 

If you lived with a cat for some time, you already know it’s the cat that trains you, not the other way around.

By learning and understanding feline body language, you can navigate around your cat’s aggressive behaviors. However, do not punish your cat when it misbehaves. It will likely cause the cat to become fearful of humans and may become more aggressive to defend itself. 

Sometimes, space and time are all an aggressive cat needs to cool off from an upsetting situation.