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Why Are Cats Aggressive?

SP Greaney, a cat owner for over 20 years, has given homes to stray cats and kittens. She has been around all types of cats.

Living in a home with a cat that has behavioural problems can be a challenge.

Living in a home with a cat that has behavioural problems can be a challenge.

Cats With Behavioural Problems

Living in a home with a cat that has behavioural problems can be a challenge. While no cat owner sets out to own a cat with behavioural problems, sometimes we adopt a cat with ongoing issues or sometimes issues arise in your household that can cause the behaviour of your cat to change.

If you open your home to a cat with preexisting behavioural problems, then you need to be aware that the road to dealing with them and fixing these issues might be a long one. Indeed, the behaviour might change in minor ways or not at all, so learning to live with a kitty that has issues will definitely be a challenge.

The World Health Organization reports that cat wounds occur between 2% to 50% of the population and that 66,000 visits to hospitals each year are related to cat wounds.

Cat Aggression Can Be Common

According to Cornell University College of Veterinary Medicine, aggressive, violent or hostile behaviour by a cat towards others is quite common. Cat aggression is often targeted towards other cats in the household, the human owner or even other pets such as dogs.

There can be a number of reasons behind cat aggression and finding out why a cat is trying to dominate other pets, is threatening other pets or you is key to understanding how to deal with the issue.

Reasons Why Cats Are Aggressive

  • Illness
  • Weaned from the mother too young
  • Abandoned
  • Fear
  • Born outside and lived in this environment since birth
  • Never been around humans
  • Abused by owners in the previous household
  • Not integrated with other animals when first introduced into the previous household
  • Attacked by other animals in previous household
  • Inbreeding

Types of Aggressive Cat Behaviour

Protecting BehaviourAttacking Behaviour

Hissing/ Spitting


Tail wrapped around the body

Dilated Pupils

Complete stillness

Yowling/ Growling

Flattened ears

Hair standing up on body

Striking out with claws

Enlarged tail

Head down with bottom up

Whiskers standing straight

Body prepared for striking at any moment

Aggressive Behaviour Targeted Towards Other Pets

Whether it is directed towards your or another animal, here are some of the most common aggressive behaviours to look out for in your home:

  • Biting
  • Striking out with claws
  • Stalking
  • Pouncing
  • Jumping
  • Howling

If animals in your household don't get on, are constantly getting into fights or there are instances where one pet is turning into a bully, you need to determine the cause.

The Animal Humane Society advises you to:

  • Get any cats that are not neutered or spayed done so immediately to help eliminate this as the cause of their fighting.
  • Ensure that cats have their own space or room to escape each other for some alone time.
  • Determine if there is an outside factor causing their aggression.
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Read More From Pethelpful

Why Is Your Cat Aggressive?

There are many reasons why your cat may be exhibiting aggressive behaviour. No two cats are the same, so take all of these reasons into consideration.


The first step to determine why the cat is behaving in this manner is to find out if there is an underlying condition behind this behaviour. If a cat is ill, they might be in pain and will not want to be around anyone. Trying to eat, being picked up or touched could be extremely painful for them. So, they are doing what they know best, striking out hoping to be left alone.

Weaned Too Young

If a kitten is taken from the mother too early then they lose the opportunity to learn from the mother what acceptable and unacceptable behaviour is. If you have ever been around a cat that has kittens, you will notice that she always take measures to correct the behaviour of the kittens. Also, when a kitten sees how their mother interacts with humans, they learn from this.


If a cat is abandoned as a kitten and not raised in a household, they can become wild. When people get a kitten for a child as a present without having researched first what is actually involved, they get frustrated if the kitten doesn't automatically behave appropriately. They are unaware of how much work is involved in raising a pet and when things don't go as fast as they like, they get frustrated and decide to abandon it. Abandoned kittens that don't have proper social interactions early on will become fearful of them.


Sometimes cats are simply scared of their new surroundings. They have been rescued from the wild, removed from an abusive home or re-homed from a rescue centre and they are simply scared of their new surroundings.

Born in the Wild

If a cat has lived outside in the city or the countryside since it has been a kitten, then they don't know any better. They have been taken from an environment they lived in and put into this new place and they have no knowledge of how to behave.

Never Been Around Humans

Cats that have never been around humans who have exhibited positive behaviour toward them simply have no knowledge of how to act or behave. So, they go into defense mode and try to protect themselves.

Abused by a Previous Household

Many cats have been raised in previous homes that did not treat them in a respectful or positive way. The cat has been hit, tortured or treated in a manner that has impacted their ability to trust humans.

Not Integrated With Other Animals

We always assume that all type of pets will get on. This might not be the case. Sometimes cats who have never been around other cats or other types of animals might not know how to react to them. They can see them as a threat and their aim is to attack anything they see as dangerous.

Attacked by Other Animals in a Previous Household

If the cat has been abused or picked on by previous animals in another household they will be frightened. This can impact how they see other animals and if they feel threatened they might strike out no matter how friendly the animals in this new environment is.


If cats are not neutered or spayed as soon as they reach six months, they can mate with each other. Inbreeding among pets can result in birth defects as well as brain issues.

Dealing With Aggressive Behaviour

  • Identify the issue as soon as you can and know the different signals that indicate to you whether the cat is in defense or attack mode.
  • Only interact with the cat on their terms. Don't try to get the cat to do what you want. Let it come to you.
  • Do not physically abuse the cat because of its behaviour. If you cannot deal with this issue then ask for advice from someone who can.
  • Use different methods to entice the cat to take their aggression out on other objects such as toys. Invest in toys that are safe but that will help keep your cat entertained.
  • PetMd advises owners to remove themselves from situations where the cat is about to become aggressive.
  • Separate pets at feeding time as well as giving each pet an individual bathroom area.
  • If the cat does something positive give them a treat and praise them.

Be Prepared

Learn the signals that will tell you that your cat is going to attack.

Using Positive Reinforcement

This method of reinforcement is used to reward the cat for positive behaviour using treats or food. What you need to be aware of is that this is an ongoing measure that you will most likely need to do for months or longer. Your cat will not change overnight, and you will need to be extremely consistent with this method.

If there is more than one person in the household, everyone needs to be on board with this training method. You cannot fall down at any time as consistency is the key here.

Positive Reinforcement Tips:

  • Implement the training prior to feeding time or when your cat is most active or playful. If they don't want to interact with you then walk away and come back at another time.
  • Always reward the cat immediately after they have done something positive and praise them for the act.
  • Do not reward the cat for bad behaviour, and make sure that everyone in the household knows what is acceptable or not acceptable.

I have used this method to stop our current cat who hated visitors, who freaked out on hearing loud noises, who would jump up on people when their back was turned, who would bite people that wanted to pet her, to stop her hissing when you approached her and to encourage her to allow us to pick her up and I've even used it to get her to do the odd trick.

It took us a year to get her to adapt to this method of training. It wasn't easy, and we still have her getting annoyed at night if people ignore her. Her behaviour now, compared to when we got her three years ago, has massively changed.

Transform Your Kitty and Your Environment

Lastly, if you are not the type of person who has the time or patience to handle a cat with issues, then you really need to think things through before you adopt it.

If you have a pet with ongoing behavioural issues, then you need to identify why they are like this. Maybe someone in the household is aggravating the cat or annoying it. The cat could be sick or they could be looking for attention.

Remember, it's your house and it's up to you as an owner to take measures to ensure that the cat is happy in its environment.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: Why is my three and a half year old cat biting the area above where she was fixed? We treated her for fleas as she was itching all over.

Answer: To double-check for fleas, use a fine-toothed comb to see if there are any fleas in her coat. If your cat is biting an area, then it could be sore, itchy or the stitches could be aggravating her skin. Also, check with the veterinarian to see if this is normal behavior after an operation. Also, check to make sure that the area isn't infected. If all of this seems to be normal then maybe try distracting her with toys or treats. Also gently move her head away from the area when she starts biting it. But be careful as annoyed cats can hit your hand with the paw.

© 2018 Sp Greaney


Sp Greaney (author) from Ireland on November 09, 2018:

@Dred Cuan, Some females are just naturally contrary. It's a pity his personally didn't pass on to them.

Travel Chef from Manila on November 07, 2018:

My cat is the most lovable cat I ever had. He was so sweet. Wherever I am, he's always there. He is really the best for me. On the other hand, his daughter and his wife are the exact opposite of him. They are totally aggressive.

Sp Greaney (author) from Ireland on February 24, 2018:

@Fay Favored, yes, I've had pets since childhood and there is always a reason why they behave in such a manner.

Fay Favored from USA on February 24, 2018:

Caring for any animal is an honor, and learning the reasons for certain behaviors makes the experience so much better.

Sp Greaney (author) from Ireland on February 09, 2018:

@BellaTheBall, don't blame you one bit.

BellatheBall on February 08, 2018:

OH! For Sure. I never went back there!

Sp Greaney (author) from Ireland on February 08, 2018:

@BellatheBall, that is awful and would make me very aware of the cat when in the same room with it in the future. Thank you for sharing your advice on these issues.

BellatheBall on February 07, 2018:

Thanks for this well thought article SP! Once I bitten by a neighbor's cat, quite severely. It was a very large neutered male. I was just standing in her home, talking to her calmly, and the cat walked across the room and, with no warning at all, sank his teeth into my leg!

It turned out that the cat had been removed from the mother at two weeks old and given to her, and after that, had never been socialized with any other people or even other cats!

In my experience, early weaning, abuse, and no socialization are the three most important factors in creating aggressive cats.

Sp Greaney (author) from Ireland on February 06, 2018:

@ Peggy Woods, thanks. There's always one who is the most trouble.

Peggy Woods from Houston, Texas on February 06, 2018:

Fortunately we have never had aggressive cats but this information is good to know.

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