Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Is My Cat Suddenly Aggressive? Vet-Reviewed Reasons

kittens training

It can be extremely disconcerting for your cat to suddenly begin to exhibit behavior that is unusual for them, especially if your once sweet kitty has suddenly become an aggressive monster. There are a few reasons that cats may suddenly become aggressive, from fear and stress to another intact cat nearby. It’s important to understand why your cat’s behavior has suddenly changed so you can start working to fix the problem.

divider cat faces oct 2024

 

Why Is My Male Cat Suddenly Aggressive?

Breeding

Male cats don’t like competition when it comes to selecting a mate, and it’s extremely common for tomcats, or intact male cats, to fight with each other for breeding rights in a certain area. When a female cat is in heat, you can expect multiple males to show up to breed with her, so there’s a likelihood that you’ll spot a few tomcat fights during this time.

Health Conditions

Pain and discomfort from health conditions can lead to aggression in normally pleasant cats. Although there are many potential causes of pain and health problems, male cats, in particular, are at a high risk for developing feline lower urinary tract disease, or FLUTD. This condition can lead to obstructions of the urinary tract, leading to an inability to urinate, extreme pain, and even bladder rupture.

aggressive cat
Image By: pixbull, Shutterstock

Why Is My Female Cat Suddenly Aggressive?

Breeding

The behavior of a female cat can change significantly when she is in heat. Typically, female cats will become extremely loving and attention-seeking. However, some female cats may become irritable and aggressive due to their hormonal changes. They may also show more aggression than normal to other cats, especially females.

Health Conditions

Like male cats, female cats can also express pain and discomfort through aggression. Female cats may experience infections and cancers of the reproductive system, including pyometra, mammary cancer, and ovarian cancer. These conditions may lead to changes in your cat’s hormone levels and comfort level, leading to aggressive behavior. If you notice this in your cat, you should reach out to a veterinarian for the consultation.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money

divider cat faces oct 2024

The 6 Other Causes of Sudden Aggression in Cats

1. Fear

If your cat is startled, they may respond with aggression until they process the situation and realize they’re safe. Cats that constantly live in a high-stress environment that makes them feel unsafe may become aggressive all the time. Cats should always be provided with a quiet, safe, comfortable place to get away from everyone and everything if needed.


2. Play

Some aggression in cats isn’t truly aggression at all. Playtime for cats is a way for them to hone their hunting skills, so it only stands to reason that your cat may start to play too rough, crossing over into aggressive behavior. This behavior can be remedied through positive reinforcement and aggressive, overly rough play should not be allowed since this can lead to injuries.


3. Territory

Some aggression in cats can arise when a new cat (or dog) enters their territory. This may be a new housemate that has been brought into the home, or a new outdoor cat that is coming around for visits, potentially unknown to you.

aggressive cat in a cage
Image Credit: Anna Krivitskaya, Shutterstock

4. Redirection

When cats are frustrated, they may lash out, showing aggression toward you or other animals in the home.


5. Dominance

Cats tend to establish social hierarchies, and therefore when new additions enter their house, the social structure may change. This can lead to aggression, as the new social rankings are established.


6. Petting

We’ve all likely experienced that odd behavior where a cat will seem to be asking to be petted, but once you do it, they bite and scratch. Why do cats do this? In all honesty, nobody really knows exactly why. It’s possible that they become overstimulated by too much touch, or maybe they simply want to be near you without being petted. Either way, it’s important to avoid touching your cat when they seem agitated. Reward them with tasty treats when they allow you to pet them without incident.

divider cat faces oct 2024

In Conclusion

Approximately 8% of animals surrendered to animal shelters in the US were surrendered due to aggression. Many of the causes of aggression in cats are manageable, but they do take time and effort to work through. If you don’t want your cat to become a statistic, make sure to focus on positive reinforcement of good behavior while discouraging aggression and other undesirable behaviors.

Also see:


Featured Image Credit: Anatoliy Cherkas, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.


How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Can I Use Dog Dewormer on Cats? Vet Reviewed Facts

Cats that have not received preventative treatment commonly contract worms, and although seeing the parasites in your cat’s vomit or stool is unpleasant...

Can Cats Eat Gravy? Nutritional Facts & FAQ

Like humans, cats enjoy a good meal. And while many people might think that all cats only eat dry food, that is not...

How Do Cats Play With Dogs? Vet-Approved Body Language & Behavior Explained

Cats and dogs are natural enemies, right? Wrong. Many cats and dogs actually enjoy each other’s company; they can even become friends! It’s...

Why Is My Cat’s Jaw Clicking? Vet-Approved Explanation!

You have heard people claim that dogs are a man’s best friend, but what about cats? Yes, they are smaller than most dogs,...

More related

Why Do Cats Put Toys in Their Food Bowl? Behavior Explained

Cats are curious, funny little creatures that sometimes do the strangest things. They can stare at nothing, hide in the oddest places, bring...

11 Orange Cat Breeds (With Info & Pictures)

Maybe it’s because they share a color with tigers or because we associate orange cats with friendly, outgoing felines. Either way, orange cats...

Can Cats Eat Crawfish? Vet-Reviewed Risk & Benefits

It’s no secret that felines are seafood lovers. Crawfish might seem safe for your cat, and you might consider giving them a sample....

Hypertension In Cats: Vet Reviewed Signs, Causes & Care

Cats are beloved family members that rely on their humans for love, companionship, and care. However, cats that receive love, high-quality food, and...

Keep reading

Does Catnip Really Make Cats High? What You Need to Know!

It’s no secret that many cats love catnip. The plant, which is in the mint family, has a potent effect on felines, making them roll around, playfully bite things, and generally act like they’re high. But what’s really going on?...

Gray Cat Enjoying Fresh Catnip_Anna Hoychuk_shutterstock

Why Do Cats Stare at Nothing? 4 Possible Reasons

Experienced cat owners know that no matter how much we bond with and learn about our pets, there will always be at least a few behaviors that leave us scratching our heads. Cats have all kinds of quirks ranging from...

Tuxedo cat sitting on the bed

Why Does My Cat Keep Meowing and Rubbing Against Everything? 6 Vet-Reviewed Reasons

If you have ever noticed a cat’s affectionate side, you may have seen their tendency to rub their faces on their owners or against their favorite objects. Or you notice a cat who raises their backside when they pass by...

grey cat rubbing againts its owners leg

My Cat Ate a Poisoned Mouse! Crucial Vet Reviewed Next Steps

Cats are natural predators. They love to hunt toys, bugs, and small animals if they get the opportunity. Many people have cats as pets for companionship and to help protect their homes from rodents and other pests (like cockroaches). Not...

My Cat Ate a Poisoned Mouse

Why Do Cats Hate Dogs? Vet-Reviewed Facts & Tips

It’s a tale as old as time, depicted in innumerable movies, cartoons, and television shows: cats hissing at dogs, dogs chasing cats, both engaging in a skirmish that results in a ball of smoke from which violent sounds emanate and...

tabby cat and a puppy on the carpet at home

Why Does My Cat Fart on Me? 7 Vet Reviewed Reasons

Everyone’s tried the old blaming-the-dog-for-a-fart trick, but can we pass the blame onto our cats if we have a feline household? Absolutely! Cats do pass gas. But if your kitty decides to do so while she is on top of...

a hand scratching cat's butt

6 Reasons Your Cat May Attack You & How to Fix It

Your normally happy cat is staring intently outside at something, tail completely straight and ears back. You wonder what is bothering them, so you walk over to your cat and they suddenly lash out at you! Even worse is when...

man playing with cat in bed_Anna Kraynova_shutterstock

How to Clean Cat Paws: Vet-Approved Step-by-Step Guide

Cats are typically considered naturally clean creatures. However, that doesn’t mean that they don’t experience some poor hygiene problems, especially if they spend a lot of time outside. A cat’s feet are vital for its health. After all, they need...

close up of a cat paw