Dog Suddenly Aggressive Towards Cat? How to Stop the Attacking

how do I get my dog to stop attacking the cat

It can be terrifying to witness your dog acting aggressively toward your cat for no apparent reason, especially if they were living peacefully before. So, what is the best thing to do if you find yourself in this situation and how do you get your dog to stop attacking the cat?

Above all else, you need to stay calm. Allowing yourself to react to the situation will only escalate matters further and may increase aggression in your dog towards your cat.

If you need to, take some time to process what has just happened, and then come back to the problem once you’ve calmed down. To ensure the best possible outcome, you need to be in control.

Why your dog is suddenly aggressive towards your cat

Once you are feeling calmer, take some time to assess what may have caused the change in behavior. There are plenty of reasons why a dog might become aggressive towards a cat out of the blue.

Some of these reasons for the aggressive behavior include resource guarding, displays of dominance, fear and anxiety, illness, or even boredom. Further down the page I have listed more detail on the reasons why your dog has suddenly started acting aggressive or attacking your cat.

dog suddenly aggressive towards cat
Dogs and cats can live in harmony, but sometimes a dog can suddenly act aggressively.

What you should do immediately

In the meantime, while you are working on stopping your dog from attacking the cat, it’s crucial to keep your pets separated. If your dog has started showing signs of aggression towards your cat, you must never leave them together unsupervised.

If your dog is crate trained, make sure to put your dog in his crate when you’re not around. Another option is that you could confine your dog or cat to one room in the house – making sure to keep the door locked when you’re away.

How do I get my dog to stop attacking the cat?

Once you have a better idea of what might be causing your dog’s sudden onset of aggression (they are listed further down the page), you need to set about correcting the behavior.

If your dog has previously lived in harmony with your cat, then there’s no reason why you can’t train him to stop attacking her.

If the behavior displayed was especially aggressive, it would be best to hire an experienced dog behaviorist to assist you.

If this isn’t possible, or if more than one dog is involved, then it might be best to separate the cat permanently. Where more than one dog is involved, this can be especially dangerous, as one dog is likely to encourage on the other’s behavior.

However, if the aggression was relatively mild, it might be possible to correct the behavior yourself.

During this stage, you mustn’t allow the two animals to interact unsupervised. If you can, keep your dog crated throughout the day while you’re at work, or allow your cat to have space outside to themselves.

If you’ve established that the aggression was provoked by illness or anxiety, it may be necessary to keep the animals separated until the issues have been addressed. However, if the aggression is the result of dominance displays or resource guarding, you can start training them straight away.

At first, it’s recommended that you start with small intervals. Allow them in the same room together for a few minutes at a time and keep an eye on your dog’s behavior. You must stay relaxed during this exercise to avoid aggravating your dog further.

If you notice your dog freezing or staring at your cat, correct the behavior immediately – staying calm but firm as you do so.

If your dog snaps or snarls, separate the animals immediately. When you do this, take your dog straight to a room in the house that can act as a “time out” area. Preferably the room should be boring and have no toys available.

Keep your dog there for ten minutes before letting him go about his daily business.

Keep trying this technique at regular intervals, and as you notice your dog’s behavior improving, try adding time to their sessions together.

Patience and consistency will be crucial at this stage. However, if you have tried this for a while without any changes, it might be time to bring in a dog behaviorist. Sometimes just having a fresh pair of eyes to look at the situation will be enough. However, an experienced dog behaviorist may also be able to pick up on things that you’ve missed.

Whatever happens, be patient with yourself and remember that correcting this type of aggressive behavior takes time. There will be days when you’ll want to pull your hair out or throw in the towel but keep at it.

With persistence and a little luck, you should be back to a peaceful household soon enough.

Reading your dog’s body language

There are many reasons why your dog could become suddenly aggressive towards your cat, seemingly without warning. In reality, however, dogs usually give plenty of warning before their behavior escalates to snapping or biting.

It’s just that the warning signs they exhibit tend to be quite subtle and are easily missed if you don’t know what to look for.

The most important signs to keep an eye out for include:

  • Freezing
  • Staring – especially if your dog is still and isn’t sniffing curiously
  • Tail up
  • Hackles raised (hair standing on end)

Other, more noticeable signs of aggression include:

  • A guttural, low growling
  • Showing teeth
  • Snarling
  • Snapping
  • Nipping
  • Biting
  • Biting and shaking

The trick here is to correct your dog before they can exhibit any of the secondary, more noticeable signs of aggression. This may not always be possible, as some dogs may lunge or snap at your cat without any warning, especially if they are resource guarding.

However, if you notice your dog staring at your cat while keeping very still, you need to interrupt your dog and correct the behavior immediately.

When you do this, make sure you stay calm but firm. Your dog needs to know that you are the leader of the pack, but it’s important that you do so without making your dog feel threatened.

Reasons your dog is attacking your cat

Now you know how to stop your dog from attacking your cat, I wanted to look a little deeper into the reasons why the sudden aggressiveness might have started.

When it comes to the reasons why your dog may have become hostile towards your cat, you need to take some time to narrow down the possibilities. Here are some of the most common reasons for spontaneous aggression in dogs:

1. Illness

If your dog is showing sudden signs of aggression, it is highly recommended that you first get them checked out by your veterinarian. Being ill or in pain can cause your dog to become aggressive with little warning.

Potential causes for this include internal injuries, arthritis, fractures, or tumors.

2. Fear or anxiety

If you have noticed signs of anxiety in your dog before the aggressive outburst, this might be another reason why your dog has snapped.

Signs of anxiety in your dog include a tucked tail, avoiding eye contact, hiding, fidgeting, destroying furniture or fixtures, pacing, whining, whimpering, and trembling. If left untreated, this anxiety can quickly escalate into aggression under the right circumstances.

Some of the most common reasons for anxiety in dogs include separation anxiety, significant life changes (such as moving), and illness. If you notice any of these signs in your dog, it would be best to address these issues first.

3. Resource guarding and possessiveness

Another one of the most common reasons for sudden aggression in dogs would be possessiveness or resource guarding. This type of aggression tends to come about when your dog feels that important resources are threatened, such as food or attention.

If your dog becomes aggressive when your cat tries to eat from your dog’s food dish, this could be an indication of resource guarding.

cat food up high
Put your cat’s food in a high place to help avoid potential flashpoints.

When it comes to the dog’s food, toys, or bed, the best thing you can do is separate these things from your cat as best as you can. Your dog needs to know that he has a space of his own and that this is respected.

Try putting your dog’s bed or crate in a room that the cat can’t access. You can also try feeding your dog separately and keeping any of your dog’s toys away from the cat as much as possible.

4. Dominance displays and hierarchy

Sudden aggression could be the simple result of your dog challenging the established hierarchy of the household. To address this, you need to supervise your animals when they are together, and when you notice any of the warning signs of aggression in your dog, correct it immediately.

To do this, you can clap or make another loud, non-threatening sound that will draw your dog’s attention back to you. Then make sure to correct your dog’s behavior while staying calm, but firm.

It may also help to establish that your cat is higher in the hierarchy than your dog. There are several ways to do this, but one of the most effective ways is to feed your cat first and to make sure that your dog sees this.

Ensure that your dog remains seated as you feed your cat, and then once your cat has started eating, you can feed your dog.

Doing this establishes to your dog that the cat is higher in the pack. It’s a simple technique that can also be implemented when you feel that your dog is challenging your authority or the authority of vulnerable adults or children.

5. Boredom and frustration

A bored dog is a dog who will get into trouble just for the sake of it. When they’re not getting enough exercise or mental stimulation, they tend to be more disruptive, disobedient, and destructive.

Although exercise requirements will differ depending on size, breed, and energy level, most dogs need between 15-60 minutes of exercise daily.

Ideally, your dog should be taken for a walk twice a day, or for shorter walks throughout the day if they are a flat-faced dog. They should also have access to challenging toys, such as Kong balls to keep them mentally stimulated.


If your dog has suddenly attacked your cat, separating them is really important. It’s the first thing that you should do.

If you cannot stop your dog attacking the cat with the tips outlined above, it is highly recommended that you hire a dog behaviorist who specializes in aggressive behavior.

Handy hint…

If you are thinking about getting a dog and already have a cat, I put a video together which gives some tips on how to introduce them properly. By doing so, you can reduce the risk of your dog becoming aggressive towards the cat, and nipping any attacks in the bud.

Marc Aaron

I write about the things we've learned about owning dogs, the adventures we have, and any advice and tips we've picked up along the way.

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