BehaviorAggressionWhy is My Younger Dog Attacking My Older Dog?

Why is My Younger Dog Attacking My Older Dog?

When you imagine two dogs in the same household fighting, you’d probably think it was the older dog attacking the younger dog. However, in most cases of intercanine aggression (two dogs in the same house fighting), it’s actually the younger dog that starts attacking the older dog.

It’s normal for dogs to snap at each other every once in a while. We have all seen one dog start growling at the other when they’re protecting a bone, treat, or are just tired. But what if that aggression escalates to a full-on fight? And even worse, what if it happens on a regular basis?

That type of extreme aggression is not common amongst dogs of the same pack. You’re probably wondering why this is happening and what you can do to put an end to it. That’s exactly what we will cover in today’s post.

Why Would a Younger Dog Attack an Older Dog?

It can be scary to watch your two dogs fight. It can be even more frightening when it happens daily and you have no idea why! To put an end to this behavior, you first need to figure out why it’s happening.

Here are 11 possible reasons a younger dog would attack an older dog. Read each one carefully and see if any apply to your situation.


This might be the most common cause. When the younger dog sees the older dog get attention from a human, they may think they’ve been forgotten. This is more common in dogs that are under the age of two and still learning how life works. If your dog only attacks when you’re paying attention to the other dog, jealousy is the likely cause.

They’re in New Territory

When dogs are in new territory, they’re in “defensive mode.” If you just brought home a new dog, they might attack the older dog out of fear, not out of anger. They haven’t learned that this new dog is part of their pack now. Any time you bring home a new dog, be sure to introduce them properly.

They’re The Same Sex

It’s common for male dogs to attack male dogs and female dogs to attack female dogs, especially when both feel like the leader. That’s why we usually recommend getting dogs of the opposite sex.

They’ve Reached Social Maturity

Dogs reach social maturity around two years old. That’s the equivalent of an 18 year old human. It’s common for 18 year old humans to go through a rebellious period…the same is true with dogs. When a dog reaches social maturity, they might push the limits and challenge authority. This behavior is much more common in male dogs.

They’re In Pain and Don’t Want to Play

Dogs do a great job hiding their pain. Your dog can be in a lot of pain and you might have no idea! If the older dog comes over to play with the younger dog and the younger dog picks a fight, they might be in pain and telling the older dog to back off. If you suspect your dog might be in pain, observe next time they walk and see if they’re favoring a leg.

Claiming They’re The New Alpha

Dogs have a natural leader hierarchy. Typically, the strongest male in the pack becomes the alpha and leads the pack. However, as time goes on, the older dog becomes weak and one of the younger dogs will now challenge them as the new alpha.

When a younger dog attacks an older dog, it might be their natural instinct to claim their spot as the new alpha. Most of the time, the older dog will back down and accept the younger dog as the new pack leader.

Doesn’t See Older Dog as Part of The Pack

When two dogs live in the same house but don’t see each other as part of the same pack, it’s a recipe for disaster. They might get along outside the house, but inside the house, they’re competing for resources. There are several reasons why dogs might not accept each other as part of the same pack. The good news is this can be changed.

One important note. It’s common for dog owners to separate their dogs and keep them in separate rooms. If dogs don’t see each other as part of the pack, this will make the situation even worse. Keeping them in different rooms will confirm the fact that they aren’t a pack member.

At the end of this article, we will go over how to use counter conditioning to get your dogs to stop fighting.

Didn’t Learn Social Skills as a Puppy

The unfortunate truth is that most puppies never learn social skills. Puppies need to learn how to play with each other, how to fight with each other, and how to be around each other. If a puppy doesn’t get time to spend around other dogs the first 12-16 weeks of their life, they might view all other dogs as the enemy.

This behavior can be corrected, but it’s much easier to simply socialize them as a puppy.

Changes in Predictable Relationship

When the older dog gets older, physical ailments and pain may prevent them from being able to respond to the younger dog with the standard body language or verbal cues. This confuses the younger dog and they will sometimes become aggressive out of fear.

Size Difference

If the younger dog is a lot smaller, they may become more aggressive in an attempt to let the older, bigger dog know they can’t take their food or toys. Ever heard of “Little Dog Syndrome”? This is where the expression comes from.

Survival Instincts

Dogs traveled in packs. When one dog becomes frail, sick, and old, it would just hold back the pack and put everyone else in danger. They would “eliminate” this dog to not slow down the group. This is just a theory, but many experts believe the aggression could simply be survival instincts.

The good news is your younger dog doesn’t have any real intent to “eliminate” the older dog. But the aggressive instinct can kick in.

Fixing The Issue

Now that we’ve covered the top 11 reasons your younger dog might be attacking the older dog (jealousy being the most common) let’s go over how to put an end to this behavior.

Identify the Primary Cause

The first thing you need to do is figure out the cause. We went over 11 causes above, did any of those stand out? Do you think your dog is just jealous? Or do you think they might be claiming the alpha role? Are they in pain?

The good news is you don’t NEED to know the primary cause to fix this behavior, but it’s good to have a general idea of what could be going on.

Counter Conditioning

Our favorite way to fix intercanine aggression is to perform what’s called counter conditioning.

To perform counter conditioning, you’ll need to have some yummy treats handy along with another person to help.

The goal of this training is to get the dogs excited to see each other instead of aggressive. Keep in mind it will take patience, but when you see your dogs getting along, it will all be worth it.

Step 1: Separate The Dogs

The first step is to put both dogs on a leash and take them outside. Have your partner walk the older (less aggressive) dog in one direction, while you walk in the younger (more aggressive) dog the other direction. You want to get plenty of separation between the two dogs.

Once you’ve had enough separation, turn around and begin walking toward each other. See how close you can get before the dog starts showing signs of aggression.

Step 2: Treat Time

Once you notice signs of aggression, begin walking in the other direction until the aggression stops. Once the aggression stops, start feeding them treats non-stop for a few seconds.

Since you’re just trying to condition the younger dog, technically you only need to give them treats. But if you’re feeling nice, you might as well give the older dog some treats!

Step 3: Repeat Step 1 and 2

Repeat Steps 1 and 2 multiple times until the dogs can get close to each other outside without showing signs of aggression.

Step 4: Bring Both Dogs Inside

Hopefully the dogs will get along inside like they did outside, but sometimes bringing them inside can cause aggression again because they feel like they’re competing over resources.

If they get along, great! The conditioning worked. If not, move to step 5.

Step 5: Remove Older Dog From The Room

Have your helper walk the older dog out of the room and don’t give either dog the treats.

Step 6: Treat Time (Again)

After a few minutes, bring both dogs in the same room and give your dog a few treats.

Repeat steps 5 and 6 several times each day. Eventually, the sight of the other dog will cause an excited reaction instead of an aggressive reaction. They know that seeing the other dog means a treat.

Article Summary: Why is The Younger Dog Attacking The Older Dog?

Intercanine aggression can be scary. Surprisingly, it’s much more common for a younger dog to attack an older dog. There are a variety of reasons for this, including jealousy, claiming alpha, fear, and poor social skills.

Separating the dogs can make matters worse because they’ll begin viewing each other as competition instead of viewing each other as a pack member. Instead of separating, use our six-step counter conditioning method to get your dogs to stop fighting.

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