Why Is My Dog Aggressive Towards Other Dogs?

Madelene Hissom · Mar 3, 2022 · All
Author: Keren Dinkin


Most pet parents know that some forms of aggression in dogs are normal. Hard stares or low growling when another animal comes near their food, for instance, is expected. Other forms of aggression, like lunging or snapping, are alarming. 

But what causes extreme forms of aggression in dogs and what can be done about it, is something that baffles most pet parents. 

If you’re looking to understand a recent change in your pet’s behavior, especially a sudden onset of aggression then we are here to help you understand the what and why. 


1. Dominance

Dominance is the most common reason why dogs are aggressive toward other dogs. While it’s true that as pack animals, dogs are sociable, packs have hierarchies. And usually, an alpha establishes his dominance within a pack through either threat or physical harm. So if you’ve recently brought home a new pet, expect your older dog to show it’s in charge. 

Expected Behavior: Walking through a doorway first, drinking or eating first, hard states, refusal to move from a sitting or sleeping spot, play fighting including mounting, being aloof.

What can you do? Remain calm, establish and enforce boundaries, counter-conditioning treatment or training.

When to get help: Lip curling, loud growling, constant barking, nipping or biting, lunging at the throat, abdomen, or back.

2. Territory

Dogs instinctively protect what’s theirs—this could be their bed, home, food, toys, even pet parents. Dogs that spend most of their time indoors and dogs that receive proper socialization and exposure to other animals during puppyhood have fewer episodes of territory-based aggression. 

Expected Behavior: Running to a window or fence to bark at animals, birds, squirrels, etc., alerting (through barking) when a stranger approaches the house or rings the doorbell, low growling when someone tries to remove food or toys.

What can you do? Block their view of the perceived “threat” and calm your dog. 

When to get help: Excessive tugging at the leash, refusal to obey discipline commands, lip curling, constant teeth-baring and barking, nipping or biting, lunging at the throat, abdomen, or back. 

3. Anxiety

Yes, dogs, like humans, experience anxiety and for several reasons. Separation anxiety, for instance, occurs when dogs become overly attached to their pet parents. In such cases, pets will feel anxious when their owners are away from home for long periods. 

Dogs can also feel stressed and anxious when the house is fuller than usual. Loud music, children running from room to room, lots of adults talking over each other, and of course, everyone wanting to pet or play with your dog—all of these could easily overstimulate your pet, resulting in anxiety. 

Expected Behavior: Drooling, excessive panting, restlessness, pacing, or compulsive behaviors.

What can you do?  Give them a private space, like a crate, to destress and a chew treat like Bully Sticks. Check out this helpful, comprehensive guide to helping your dog overcome separation anxiety.

When to get help: Destroying furniture, soiling inside the house, relentless barking when left alone, depression.

4. Illness

Did your generally well-mannered and sweet-natured dog suddenly turn aggressive? If so, the underlying cause could be the onset of an illness. When dogs are unwell, they feel scared and act out of character. One way to determine the reason is to be observant while repeating the behavior. For instance, if your dog generally likes ear scratches but snarls if you touch his ears, your dog could have an ear infection.

Expected Behavior: General irritability, refusal to move, low growling or snarling, even warning snaps if the injured or painful area is touched.

What can you do? Symptoms of illness in dogs vary from sudden weight gain to weight loss, limping, fever, decreased play, change in gait, etc. Even if your dog doesn’t show any outward symptoms, please take your dog to the vet. The sooner, the better.


When your dog shows forms of aggression, it's important to understand that they are simply reacting based on what they perceive about the circumstances in which they find themselves. Getting anxious, shouting, or worse, being aggressive towards your dog are all unhelpful behaviors that will only worsen the situation.

Understanding your dog and its insecurities, remaining calm and assertive, and identifying and handling potential triggers ahead of time are better ways to prevent behavior-related issues from escalating. You could also try positive reinforcement (verbal praise and treats) when your dog behaves well.

Alternatively, you could also look into professional behavior modification training. Although the science on its efficacy is limited, some pet owners have claimed to see a significant change in their dog's aggressive behavior.