What should I do if my cat becomes aggressive?

Aggression is alarming behaviour directed towards a person or animal.

When cats show signs of aggression – an important survival skill that has helped felines survive in the wild for centuries.

Why do cats suddenly become aggressive?

Any sudden change in your cat’s behaviour is a cause for concern.

Cats who suddenly become aggressive are usually suffering through some sort of stress, pain, or underlying health problem. If you notice your cat has suddenly become aggressive, please contact your vet for advice.

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What are symptoms of aggression in cats?

Aggression in cats can include one or more of the following behaviours:

  • Hissing
  • Biting
  • Growling
  • Clawing
  • Spitting
  • Scratching

Some cats may try to make themselves look bigger and more intimidating by staring, howling, or stiffening their legs and tail. Other cats might adopt a self-protective posture and attempt to look smaller by crouching, tucking their tail under their body, or flattening their ears.

Unless it is necessary to approach them for their health and/or safety, cats who are displaying any of the above behaviours should be left alone.

It is never acceptable to punish a cat for being aggressive.

At times, your cat could appear aggressive, when really, they’re just displaying a natural part of play. Your cat’s behaviour is considered ‘aggressive’ when they actively seek to harm humans and/or other pets.

If you’re concerned about your cat’s aggressive behaviour, speak to your vet about being referred to a qualified feline behaviour expert.

Reasons your cat is being aggressive

There are many possible reasons behind your cat’s sudden aggression:

Illness and chronic conditions

Before assuming your cat’s aggression is down to an attitude problem, it’s important to rule out any potential, underlying health conditions. While cats tend to hide their pain, because it makes them feel vulnerable, your cat is likely to become irritable if they’re uncomfortable.

Always take your cat to see a vet if they become grumpy or if refusing to be stroked is out of character for them.

Unfamiliar scent

Cats can get cross when they’re disturbed by the scent of another animal, especially in their own territory. While territorial aggression can be displayed towards anyone, in the form of hissing, felines usually direct any angry behaviour at other cats.

New arrival

Have you recently welcomed a new baby or pet? If so, congratulations!

You may feel extremely excited about your new arrival, though your feline friend could consider them ‘an intruder’. Aggression aimed at a new arrival, in the form of growling and hissing, might be linked to your cat’s territorial nature.

Keep your new arrival away from your feline friend until you’ve spoken to a vet for advice on how to handle such a stressful situation.

Redirected aggression

When cats are overstimulated, they can attack other cats, dogs, and/or their pet parents. For example, if a cat spots a bird sitting in a tree, they’ll find that stimulating, until they’re unable to catch the bird and end up feel annoyed – that experience could lead them to redirect their frustration at those around them.

Maternal instinct

A mother may display aggression if she feels her kittens are in danger.

If your cat has recently had kittens, keep her content by providing a safe space for her away from loud noises and distractions.

During the first few weeks of your kittens’ lives, limit your interaction with their mother so she can tend to her new family.

What should I do if my cat is aggressive towards other cats?

Understanding the reason your cat has become aggressive towards other cats is a useful place to start.

Most fights between cats are linked to territorial disagreements, food, or fear. Take your cat straight to the vet if they’ve been injured in a fight.

Once your cat has been checked by a vet for any underlying illnesses, and you’re certain they don’t have injuries, your cat could be aggressive towards other cats because they’ve moved to a new home or experienced a change in their routine.

Seek advice from a vet to remedy your cat’s aggressive behaviour towards other cats.

What if my cat bites me?

Any cat bite will require medical attention – if you are bitten by a cat, go to hospital immediately. Cat bites can cause serious infection if left untreated.

It can be upsetting when cats bite their pet parents, so it’s important to discuss any concerns about your feline friend’s aggressive biting habits with your vet.

Looking for more cat advice?

We’ve written some handy cat advice guides, to help you unlock the secrets of your mysterious moggy.


Need cat insurance?

Cat insurance can help cover the cost of veterinary treatment if your cat gets injured or falls ill.


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