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Why does my dog hate other dogs?

You dream of being able to take your normally well-behaved dog to the dog park or on walks, but they act aggressively when they see other dogs. 

It may seem like a Jekyll and Hyde scenario. Your normally sweet calm fur baby turns into a mass of teeth and growls, leaving you confused and concerned. 

You may feel embarrassed, afraid, or as if your authority has been challenged. Once you understand why your dog hates other dogs, you’ll be better able to deal with the behavior. 

Why does my dog hate other dogs?

It’s easy to see your dog as acting out when they act aggressively towards another dog. However, the root of the behavior is rarely simply aggression. Dogs are social animals, and they generally want to get along with each other. When a dog hates other dogs, there’s a problem that needs to be corrected. 

Defining Hate

It’s important to consider what you mean when you say your dog hates other dogs. Are they not interested in interacting with them, or are they aggressive when they encounter another dog? 

If your dog prefers to be left alone instead of playing with other dogs, it may simply be their personality. However, if they are aggressive, there’s a deeper issue that needs to be addressed. 


You may think aggression is the root of your dog’s behavior, but fear is often the underlying cause. Dogs have the same fight-or-flight reactions to fear that humans do. When they are afraid, they will either act aggressively, prepared to fight, or flee. If they don’t feel able to flee, this leaves fight as the only option they see. 

Many things can cause a dog to be afraid of other dogs. Lack of socialization is the most common cause. Just like a child learns to speak and what is socially acceptable from interacting with others, dogs learn communication skills and social etiquette from other dogs. 

If they haven’t been properly socialized, they don’t know how to react to others, and fear is a common reaction. 

Jealousy/Protecting Owner

Does your dog seem fine with other dogs when you aren’t nearby? If your dog acts aggressively any time another dog comes near you, they may be jealous. This is particularly likely if they resource guard food or toys as well. 

Your dog may also see other dogs as a threat. Dogs that are considered “guard dogs” are more likely to perceive others as a threat to you, but it can happen with any breed. 

It’s also possible that you are sending fear signals when you encounter another dog. Dogs are very attuned to their owners. If you begin breathing faster, tensing your muscles, and clenching your hands, your dog will pick up on this. They will get the message that you are afraid, which can trigger them to protect you. 

Perceived Threat

Your dog may perceive other dogs as a threat. Just as a dog will act aggressively to protect you, they will also do so to defend themselves. It could be fear or a signal that the other dog is sending. 

Aggressive or Reactive Disposition

Some dogs are naturally more aggressive or reactive. This can be due to a combination of factors. Some breeds are more likely to stand their ground or fight when encountering a stressful situation. Some dogs or breeds have a more nervous disposition, which makes fear aggression more likely. Of course, each dog is an individual and temperament can vary greatly among dogs of the same breed. 

In addition to having a naturally reactive disposition, some dogs are reactive because of conditioning or lack of socialization. There is no clear line between nature and nurture, and placing blame on the dog or the owner isn’t helpful. 

Regardless of the reason, it should be understood that a dog with a reactive disposition will require extra effort and training. 

Pregnant or Nursing

When a dog is about to give birth and nursing, hormones that cause them to be protective of their pups flood their system. You should expect your dog to accept your presence, but keep it limited the first few weeks.

However, you should not expect them to tolerate other dogs around young pups. They are instinctually wired to hate other dogs during this period as a way to protect their babies. Once they are weaned, the mother should allow them to interact with other dogs. 

Why does my dog hate certain dogs?

Your dog gets along great with most dogs, but there are a few dogs that they seem to hate. Why? 

Historical Interaction

If your dog has had a bad experience with a dog in the past, they may preemptively act aggressively when they see them again. Dogs have a strong associative memory. This means your dog won’t remember exactly what happened with the dog, but they will remember feeling scared, angry, or aggressive. 


Smell is a large part of communication for dogs. They get lots of information from a dog’s smell, even from a distance. They may smell something that suggests the dog is aggressive or even sick. They may also identify the dog as a sexual rival, because they can smell sexual maturity. 

Energy Level

Does your dog seem to hate dogs that are high-energy or very friendly? You’ve probably encountered someone in your life that was just too much. They are too loud. They get into your personal space. Their energy level is simply too much for your comfort. 

Your dog may be put off by a dog that is too energetic or playful for them. This can lead them to act aggressively as a way of saying, “Hey, leave me alone”. 

Why does my dog hate one particular dog?

Your dog is great with other dogs. However, there is one dog that they always have a problem with. Why do they hate them? 

Aggressive Behavior

The other dog may be acting aggressively. Aggression can be more subtle than growling or attempting to bite. Raised hackles, the tail straight up or over the back, and prolonged eye contact are also signs of aggression. 

Similar Status

Dogs are more likely to act aggressively if they are of a similar status. Dogs fall into alpha, beta, and omega categories. Alpha dogs are the leaders of the pack. Beta dogs are subservient to the Alpha only. Omega dogs are subservient to beta and alpha dogs. 

When the hierarchy is clearly defined, such as when a beta meets an alpha, there’s no need to fight for status. However, when an alpha meets an alpha, or a beta meets a beta, they may act aggressively or fight to determine who is “top dog”. 

Lack of Socialization 

The dog that your dog hates may not be properly socialized. A dog that hasn’t been socialized doesn’t understand cues from other dogs. They may act inappropriately, and your dog may find it offensive or not realize there’s a misinterpretation. 

Why does my dog suddenly hate other dogs?

Your dog has never had a problem with other dogs. Suddenly, they seem to hate every dog they meet. This leaves you wondering what happened. 


Adolescence is similar for humans and dogs. Bodies are changing, hormones are raging, and behaviors change. Regardless of whether your dog is spayed or neutered or intact, they will experience puberty. 

Aggression can be a result of changing hormones or increased confidence in their ability to fight. Dogs who are inclined to be aggressive will normally begin to act aggressively during this time. 

Traumatic Experience

If your dog has had a traumatic experience like fighting with another dog, they may fear other dogs. This can lead them to act aggressively towards other dogs as a fight or flight response. Your dog’s associative memory may tell them dogs cause them pain or fear, instead of being limited to the dog that attacked them. 

Pain or Illness

This is a common issue with older dogs, but it can happen at any age. When you are in pain or don’t feel well, you likely have a shorter temper and less desire to socialize. It’s natural for dogs to feel the same way. 

If your dog has a condition like hip dysplasia or arthritis, they may hate other dogs because another dog attempting to play is painful for them. It’s also possible that they are simply grumpy because they don’t feel well, and don’t want to be bothered. 

How to get my dog to be more friendly towards other dogs?

It’s always desirable for your dog to be able to interact with other dogs. Not being able to do so limits their life, and yours, in important ways. It also puts you and your dog at risk of injury, and can lead to financial liability claims if your dog attacks. 

Understand the Cause

The first step is understanding the cause. Is your dog reactive by nature? Are they jealous or simply trying to protect you? Could there be an illness or injury? Is their reaction fear-based? 

Knowing why your dog hates other dogs is important because it allows you to empathize with them. If your dog is reacting out of fear, knowing that will allow you to handle the situation gently.


Desensitization is helpful in most situations. The exception is a pregnant or nursing dog and a dog that has an injury or illness. 

Desensitization works if you set your dog up for success. If your dog reacts to a dog that is 20 feet away, you’ll need to keep them 40 feet away from other dogs to begin with. Start with a distance that you know your dog can handle without reacting. 

When they encounter another dog and don’t react aggressively, give them a treat and lots of praise. Repeat this over and over until you feel like you can increase the difficulty. Begin letting the other dog get a little closer. Continue giving praise and a treat each time they don’t react. Keep moving the other dog closer incrementally. 

Depending on how strongly your dog reacts, you may want to begin with your dog in a fenced-in area. If there’s no fence, a leash is a requirement so you can control the exposure. 

An animal behavior therapist is in the best position to help with this work. If that’s not possible, find a friend with a well-behaved dog who is also leashed for encounters. 


If your dog has reached sexual maturity and hasn’t been spay or neutered, doing so may help with aggressive behavior. The biological drive to mate and hormones can certainly contribute to aggression, and dogs are more likely to fight if they are attempting to win a female. 

Vet Visit

If you have any suspicions, your dog is sick or injured, take them to the vet. You may still need to do desensitization training, but treating the dog should come first. Once they are healed, then begin desensitization training to correct any behaviors caused by associative memory. 

For example, if your dog has arthritis and is put on pain medication, they may still react as if another dog will hurt them. Their memory tells them encountering other dogs is painful, and it takes time for this to be adjusted.