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Dealing With an Aggressive Cat? 7 Reasons Why Cats Become Aggressive

Cats don't get aggressive out of nowhere. An aggressive cat is usually behaving that way for a good reason. Here are seven reasons why cats become aggressive — plus the warning signs and how to handle each.

JaneA Kelley  |  Nov 8th 2019

Even the most experienced cat caretakers can find themselves charged up on adrenalin when having to face a cat in the midst of a fit of aggression. But encountering a hissing, growling, screaming, and possibly even scratching and biting cat can strike terror into the hearts of people who don’t know how to handle an aggressive cat. But cats don’t just suddenly go crazy: There are almost always warning signs and there’s almost always a good reason for cat aggression. Here are seven reasons why cats become aggressive and how to handle an aggressive cat.

1. Cats Become Aggressive Because They’re in Pain

An angry cat growling, hissing or hiding.

An aggressive cat might be responding to pain. Photography ©points | Thinkstock.

Cats who are in pain will respond with hisses and swats when sensitive areas are touched. My cat, Siouxsie, does this if I accidentally put pressure on her sore hips. A hard yank on the tail, for example, can be quite painful. Ignore the warning signs and a scratch and possibly even a bite may follow. This is especially true if the pain is a result of physical abuse such as being kicked or hit.

2. Fear Can Cause Cat Aggression

A terrified cat will respond with body language that’s obvious to an experienced cat caretaker: She will turn sideways and puff up her tail and fur in order to look larger. Her ears will flatten backwards, she will hiss and her pupils will dilate. Attempting to approach a cat in this state is risking an aggressive reaction, not because the cat dislikes you but because she’s in the middle of a panic reaction.

3. Hormones May Cause a Cat to Become Aggressive

A cat who is not spayed or neutered is much more likely to be aggressive. Male cats in particular are biologically wired to fight with other male cats when females in heat are present. If you see two cats fighting, do not physically intervene because you will almost certainly become the target of the cats’ aggression.

4. Cats Can Get Aggressive Due to Frustration

“Redirected aggression” is the term for violent acts carried out by cats because they can’t reach the object of their predatory passion. For example, an indoor cat who sees another cat walking by or marking his territory in “his” turf may get into a highly reactive state. At that point, anyone unfortunate enough to be nearby, whether that’s another cat, a dog or a person, may end up on the receiving end of the cat’s aggression.

5. Cat Aggression Happens Due to Stress

A kitten hissing with his ears flattened back.

An aggressive cat may be responding to stress within your home. Photography ©Ornitolog82 | Thinkstock.

If a cat lives in a highly stressful environment — for example, a home in which people are fighting or a home with too many cats — it’s quite possible for that cat to be quick to respond aggressively. Like children who live in homes with a lot of verbal and physical violence, or a lot of unspoken anger, cats often act out the dynamics of their human families.

6. An Aggressive Cat Might Be Responding to Trauma

Don’t laugh: Cats can suffer from post-traumatic stress. Their brains are wired similarly to ours, and the effects of chronic anxiety from past human violence or struggling to survive on the streets can lead cats to become aggressive. In order to resolve this issue, a short course of anti-anxiety medication (prescribed by a vet, of course; don’t give your cat your antidepressants, please), homeopathic remedies or flower essences can help make a cat less reactive to triggers.

7. Chemical Imbalances Can Cause Cat Aggression

This is by far the rarest reason for cats to become aggressive. But like humans, some cats simply have biochemical imbalances that affect behavior. For these cats, antidepressants or anti-anxiety medications can be a lifesaver.

The bottom line on handling an aggressive cat

No matter what the cause of the aggression, there are almost always warning signs. If you understand feline body language, you’ll be able to see that your furry friend is getting wound up before the situation escalates to a crisis point. If you have a highly reactive cat and you want to help him or her, be aware that it will take time and patience — but take it from a person who has rehabilitated traumatized cats: The reward is so worth the effort!

Tell us: How about you? Have you had an aggressive cat? Were you able to help your kitty feel better and become less reactive? What did you do to help her? Have you ever been unable to help an aggressive cat? Share your thoughts in the comments.

Thumbnail: Photography by elwynn / Shutterstock.

About the author

About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.

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    Contributions

    144 comments on “Dealing With an Aggressive Cat? 7 Reasons Why Cats Become Aggressive”

    Comment navigation

    • Herf says:

      You had me until you mentioned homeopathic remedies as a viable treatment.

      Homeopathy has been debunked many, many times. It is a scam. If you know anything about science and/or critical thinking, one can figure this out.

      Reply
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    • Michael Yearout says:

      When we adopted Emma she was three years old. The shelter did not know much of her history. The aggression started just a few days after we brought her home. We figured she had been abused in her first three years and probably beaten with a newspaper as she was afraid of newspapers. We think she was afraid of humans and had lost all trust in them.
      We learned how to recognize when she wanted to be left alone and we left her alone at those times. We were patient, giving her pets and love when she would accept it. It took years but with patience and love she finally started trusting us and turned into a loving adorable cat that we loved and still love.

      Reply
    • Aubree hixon says:

      My cat had kittens like my other female. She had a hard time i helped her the whoe time. She would steal our othet females kitten, usually only one of them. She have one less than our other female. Ever since the kittens were old enough to be on regular food she’s been grumpy as we call it. She growls at the sight of another of our cats. She attacks if they get too close. It’s more annoying than anything. Any advice?

      Reply
      • sukie Rix says:

        I had the same experience. I had heard that related cats will share kitten duties, but not with my mother and daughter pair. When the kittens were tiny they spent the whole time stealing each others kittens. I even had to rescue one when they were having a tug of war with it! It got worse when the kittens were older. One night the two mothers set up a noisy territorial catawalling. I rushed down stairs to find the mothers threatening each other while all the kittens were hiding! I had to keep them separate until I found new homes for the kittens, then peace was restored. I suppose I should not have been surprised, Cats are not social animals like dogs.

        Reply
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    • Lani says:

      I have a three year old neutered Tabby who didn’t become aggressive until I took in a second cat. Now he has a strange routine. At 6 pm he starts hissing and growling and demanding to go out. He stays out all night coming in about 9-10 am. He eats and goes straight to my bed where he sleeps all day and is perfectly docile.He has bitten a few people who have tried to pick him up. I tried giving him prozac and CBD oil but he won’t take it.

      Reply
    • Aly Vanderlinde says:

      My cat, over the last few months has started attacking my son at random!! My son will just be walking by and he’ll hiss and scratch him!! My son LOVES this cat, and he doesn’t do anything to him! I don’t know what to do! I can’t keep him if he’s going to scratch, his and spit and GROWL at my son, but my son doesn’t want me to try to rehome him. This cat is very much loved, but not to the detriment of my family! What can I do?

      Reply
      • Mike says:

        May be what you don’t know your son may have at some point in the past hurt her or him, so.cats don’t forget their trauma they may have suffered , sorry if this may sound that your son did something, but I know behind parents back children do often abuse pets, like pull their tail, kick them, or throw them etc, or even beat them with objects like sticks etc, cats don’t hiss at anyone unless they feel uncomfortable, especially strangers coming near them, but if they hiss towards regular visitors or member of your family, that is what it is and cats cannot talk so they can’t tell what happened when you were not there, only your son can tell. My apologies if I sound like accusing your son .

        Reply
    • Jena says:

      My male cat who is 2 keeps running outside and yesterday he ran outside as I opened the door just for a second, he was in the street and I was about to pick him up when he suddenly attacked my hand and my leg.I am terrified. He won’t stay inside the house and would just run as soon as the door opens.He is always meowing very loudly. My parents think that he isn’t happy here with us and that we are being cruel by keeping him inside when all he wants to do is leave this house. I don’t know what to do? Should I just let him go? Or should I keep a female kitty in the house, may be that way he’ll be happy or not? Please reply.please!

      Reply
      • JosieCat says:

        If he neutered? If not, that’s the first thing you need to get done, so he’s not controlled by his hormones and wanting to go out looking for females.

        How much attention does he get? Playing with him every day and before a meal time will greatly help to dissipate him energy. Use a wand toy he can chase. (Wand with a string and a “bird” at the end type of toy.) You WANT to make him tired. That will use up pent up energy and help lower his aggression also. Then feed him, and he’ll see the food as a reward. Don’t give up on him. And don’t just let him run around outside.

        I would try what I’ve suggested before you make any attempt to introduce a second cat. That could backfire big time. He needs to feel totally comfortable in your home before you might bring in another animal, which could really upset the apple cart further.

        Best wishes to you, and your cat.

        Reply
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    • Jena says:

      Hi !
      I’m really scared and concerned about my male cat who is 1. So this incident happened today when my cat came from my friend’s home who has a female cat. My cat came home after 4 days. When I took him inside he lied down on the floor and I started to pet him then I tried to pick him up but he won’t come so I tried again but he won’t come so then I just got up and was gonna go when I suddenly saw that my cat stood up, was staring right at my face and suddenly jumped at my leg and won’t stop! I somehow managed to ran away and came to my room, now I have bruises on my leg due to his nails, but he didn’t bite ! Now I’m not even going to him, I’m just here inside my room ! I’m really worried about my cat, I really love him and I hope there’s nothing wrong with him! Can you please tell me why is he doing that!?

      Reply
    • Ryan says:

      Hi,

      I need some advice to understand my kitten more, He’s 6 months now, very confident, sociable and very sweet. He loves meeting new people and will tend to go up to them straight away to cuddle people. He walks on a harness perfectly fine. Understands code words Like nom nom for feeding timers, walkies for going for a walk, he alway excited to go out for walks with his tail held high straight and pointing up.

      We have trained him very well and it’s not been hard work. He also does not mind baths, very weird for a cat but it’s great weird.

      Anywho, there is one thing he does that is out of character for us and that is when we take him to my sisters house he is fine but when the children comes in he lash out and is on edge. He even lashes out at me when I go near him while in her house. When the children are not there he is fine. Now my sister has a cat but he is timid and shy so stays away. My kitten will attempt to play but will stay away from her cat when he hisses at my kitten.

      He fine in any other household with children and again as I said he loves meeting new people including children, however just not my sister two young once’s why might this be?

      Reply
      • Catster Admin says:

        Hi Ryan,

        Sorry to hear that you’re dealing with this! This sounds like a specific incident that might benefit from the individualized attention of a behaviorist.

        Reply
      • Aly says:

        Sometimes kittens don’t like certain kids, if they like kids at all!! They can be (the kids) way too hyper for a kitten. Also your cat may not like the way they handle him. You’re not always around to see how they treat it. I’d say don’t take your cat there anymore. They’re not like dogs, and they aren’t always social. So I’d say if your cat is uncomfortable there stop taking it there.

        Reply
      • JosieCat says:

        I’m guessing that at some point, unbeknownst to you or your sister, one or more of her children did something to the cat that either hurt or scared him. Maybe not deliberately, but kids often don’t know how to deal with cats, in particular. And cats can have long memories about such stuff.

        Not unusual that your cat and your sisters would have some “issues” together. Cats are territorial, and their different personalities also feed into how they deal with that. I hate to say it, but I would suggest you probably should leave your cat at home when you visit your sister and her kids )and their cat), if at all possible.

        Reply
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    • Chrissy Randall says:

      My grandson cat, Theo, has come back to live with me. He used to live with my daughter. He has always been an indoor cat. I have a screened back porch that he would love sitting out on all day! I also have dog that Theo grew up with. I started letting him out on a leash and harness. He loved it. He now goes in/out the doggie door and absolutely loves it. Just recently after my daughter came to visit, Theo ran and hid from her. Then he has been very aggressive at night towards the dog and us. Now for the past couple of weeks he has been consistently aggressive just about every night. We thought maybe he is/was mad at my daughter and acting out. Maybe it is because he has been going outside. Any insight? I think I remember that he has had several “”bouts”” of aggression, even before coming back to stay with me. He also has a constant stuffy nose and sinus trouble. Could that have anything to do with aggression?

      Reply
    • Jean says:

      I have a female, formerly feral cat who has become aggressive toward the other cats in the house, but more affectionate with me. When I first rescued her, she preferred the company of cats and avoided me, except at feeding time. Now, she’s done a complete 180 – follows me around the house, sits on my lap and swats at the other cats, including her kitten (I rescued both before winter set in.) I think she was the queen of her feral colony, so is she trying to re-establish her place as head of the tribe now?

      Reply
    • lorrie-ann gheraldi says:

      I have a 8 year old female non-spayed cat and a 8 year old (soon to be 9) year old spayed dog(shepherd/pointer/pit). Both have been living together, sleeping together, playing for several year now. A few days a go I came back from walking the dog and while my dog was drinking her water, my cat jumped at her with all four sets of claws out and attacked her. My dog was afraid so she backed away but the cat came chasing after her, hissing and swatting. I stepped between them and my cat tore my arm up, bit and scratched my legs and feet.
      My cat now stalks and antagonizes my dog. My dog is starting to be afraid to walk around the house. I notice when she comes home after I walk her she starts to shake before we get in the door and she won’t go near the room the cat is in, even with the door closed. I have them currently separated as much as possible. HELP?!

      Reply
    • morgann anderson says:

      hi,

      My cat Lilly is two years old, she has become very aggressive. Every morning and night she will pounce on me and my partner and will not let us walk around without her attacking us, she makes a crying sound while doing this. she is fine during the day and i’m unsure what im spouse to do as it’s getting out of hand i have sctraches all over my arm and i can not walk around my house during these times incase she attacks. We have moved houses 4 times due to building and renting but she has always been in these moods but it has gotten ALOT worse. What do i do?

      Reply
      • Lucinda Rezabek says:

        Have you played with her in the past with only your hands or not using any toys? It sounds like she has a lot of pent up energy and for some reason thinks you and your bf are the toys! Kitties need their people to play with them hopefully at least 15-20 mins a day, but for sure use some sort of toy. My kitty loves a simple short black satin string. I pull it around for him on the hardwood or linoleum floors and it wears him out fast! It’s funny as heck too! He also loves the toy that is simply a golf ball sized ball in a circular track. I’ve yet to have a cat that didn’t love both of those things, oh and maybe a paper bag open on the floor!

        Reply
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    • Dané says:

      My cat who is 14 years old always was a very loving cat and about a year ago she had te go on a diet because she’s overweight. She is now very aggressive and randomly attacks me. Could this be because of the diet? And should i take her of it.

      Reply
      • belvoir admin says:

        Hi there,
        We’re sorry to hear you’re experiencing this. We suggest asking a vet for the best advice when it comes to cat diets.

        Reply
    • Mengxue Cai says:

      Hi!
      I moved in with my bf, he has a cat & I have a cat. Both are female, 2-2.5 years old and fixed. They were separated for 2 days, one in living room and one in bedroom. They have separate cat litter and food. I wipe their scents onto each other. Then they were introduced to each other in 2 separate carriers. I’ve also brushed them with the same brush and tried to mix the scents, but my cat growls & hiss at the brushes too. They were introduced to each other on 4th day, with toys and snacks for distractions. They didn’t fight, only hissed at each other. Over the last week, his cat has calmed down, no more growling or hissing or charging at my cat. However, my cat is still making growling, hissing and loud screaming. They had been eating in each other’s bowl and using each other’s litter box even thought it’s at different places. My cat stays in the room while we’re asleep. And it seems like she acts territorial with the bed or me? And growls extremely loud when his cat try to come into bedroom. They do this like 5-6 times throughout the night. The way his cat meows, sounds more familiar now. But my cat is still growling reallllllly loud. Any suggestions? Thank you in advanced!

      Reply
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    • K Holland says:

      Our 9 yo, female (not spayed) cat, has suddenly become aggressive to the other 3 neutered male cats. Her belly looks like she’s pregnant, but she is a strictly indoor cat making this IMPOSSIBLE. We have had her and her siblings since birth, they all cohabitated, without any problems, to this point. Now she goes on the attack on the male cats and it scares them and us. Should we take her to the Vet?

      Reply
    • Lachaelg says:

      I have a cat, now almost 3y/o, rescued from the street, nursed to health. She always had a weird behavior. Doesn’t meow often and showed very little affection but would sleep next to myself and spouse in bed, or my son. Would also sleep on the foot rest of our recliners and would allow us to hold her occasionally. All of a sudden she is aggressive, hissing, slapping, growling and screaming whhen we get close. She is so aggressive currently for a few weeks and I cannot catch her to take her to the vet..no idea what to do.

      Reply
    • Belina says:

      A year ago I lifted a kitten lying near the garbage bin. She has now grown and given two kittens who are two months old. I guess she is now again a month pregnant. My cat has all of a sudden started behaving rudely to her kittens. Few days back she couldn’t live without then would cry if they are not around, calling them, searching them. But now all of a sudden a different behaviour. Can you help me out with the reason for this kind of a behaviour. She isn’t allowing anyone next to her. I tried checking if any wounds on her body but everything seems fine.

      Reply
    • Monica Ingber says:

      My cat is docile and can usually be picked up and cradled like a baby. Over the last two days, he has reacted in a ‘spooked’ way when my husband picks him up and literally jumps out of my husband’s arms. He has badly scratched my husband in the process of trying to get away. My cat doesn’t react this way with me at all. He follows me around and loves to be held and fussed on. He was a stray before we adopted him, so we don’t really know his history past that. My cat is 4 1/2 years old and other than going away for a couple of nights a week, my husband is usually home with him. I don’t know why this behaviour has started. Any advice?

      Reply
    • stacey says:

      Hi , my cat is 10 months old , i rescued him from someone that wanted to give him away on facebook.. we love him despite him being feral at times. we buy him toys play with him and feed him everyday he recently learnt to jump our gate and run down the stairs we live on a main highway and the back is the bay (bushes) and water where people walk their dogs every day , so twice now he has run away ” roamed ” the first time we found him in the downstairs neighbours yard where there was a cat he was screaming my daughter grabbed him but he puffed up in a ball ( around his neck) something was wrong got him inside and he violently attacked my daughter we never seen him act like this before.So today he roamed again pushed the window open and got out down to the bay this time , was missing for a near hour but we found him, got him home again and this time attacked my partner and nearly me what do i do , does he hate us ? what should i do ,

      Reply
    • Sean says:

      I adopted my (2 y/o neutered) cat about 6 months ago. She was energetic and felt at home quickly. Then, I let her out in my backyard and have continued doing so for a few months. Now that it’s raining season, I have tried to keep her inside and she tries to escape every chance she gets. She’s also aggressive towards the neighbour’s pets. What are the things I can do to curb her wild behaviour?

      Reply
    • Zee says:

      My cat is very attched to me. There was point where be does not allow me to put him down. He wants me to carry him. Once i put him down he gets angry and wanted to attack me. 1 mth prior to that he attaccked me bcos he can sence pregnant cat was at the door outside. He got angry and attacked me viciously. What can i do? Now i put him in a small room by himself. Lure him into a carrier to lock him up before i clean up his room n litters and give him food and water. Please advice…i miss touching and hugging him.

      Reply
    • Jossie Moran says:

      I’ve had a cat since he was 8 weeks old..he is neutered and 12 yrs old..inside cat all his life..apparently always docile and allowed me to pet him even on his stomach..out of the blue, without provocation and while letting his stomach, he turns on me and bites my arm hard..I’m concerned and shocked at his reaction..he is healthy and with no medical issues..I appreciate your opinion..thanks..!

      Reply
    • Camila says:

      The day she was spayed, my feamale cat attacked me really bad, and I yelled and ran and she kept scratching me and biting me until I got out of the house. Then one or two weeks after, my cousin scared me and I must have yelled the same way, that the cat attacked my cousin, I don’t know if she was coming for me but I ran and she got my cousin the same way she attacked me. Now three months after being spayed we brought her to another country, also she might have gotten nervous because of a sound or the amount of people in the house and she came to attack and since I cannot react another way I just started yelling and running again and she kept following me and then kept acting really aggressive. Does any of these things are linked or could anyone help?

      Reply
    • Rita Bellin says:

      I have 2 female cats(sisters). They’re 6 years old and lately are growling and hissing at each other. And now are urinating and pooping outside the litter box. I had the one checked by the vet and she’s fine. He said it was behavioral. I use that feliway and nothing helps. Any suggestions?

      Reply
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    • Lyndsey says:

      I left to go interstate with my family 5 yrs ago & couldnt take my cat with me as we were staying with friends for a short period of time & didnt have a home.
      My female cat was very close to me,always slept close and never went to anyone else.
      I did eventually find somewhere but when I returned to get her,she didnt want a barr of me and she was extremely aggressive.
      She flicks her tail at me when im not near her and runs away.
      I have not been able to take her back home with me.
      I visit my parents and its always the same.
      I have had “moments” where shell purr and let me touch her,but mostly she “hates me”..
      What can I do?
      She was such a beautiful cat..
      She not only does it to me,she does it my mum and sometimes when shes lying near my dad and hes gone to touch het shes bitten him!
      Has she been injured or is this all anxiety for me leaving her?
      I did live here for 6 mths but nothing changed..

      Reply

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