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Why is my dog aggressive towards puppies?

Having an adult dog to help train your new puppy can make the process much easier. Puppies instinctively learn from the example set by other dogs, just as they learn from their mother early on. However, your dog can also become aggressive with your puppy, which creates it’s own set of problems. 

Why is my dog aggressive towards puppies?

Some dogs seem to dislike puppies. However, getting along with puppies, or at least tolerating them, is required if you plan to socialize your dog. Even a simple walk becomes risky if your furry friend is aggressive towards pups. Things can turn ugly very quickly, leaving yourself or the pup hurt. Why are dogs aggressive to puppies? 

Behavior Only Seems Aggressive to Humans

This is the most common scenario, and the best one. Dogs have their own ways of interacting with each other. What can look mean or aggressive to us can simply be your dog’s way of teaching the pup or setting boundaries. Your dog may knock a puppy down, pin it to the ground, growl, or lunge at the pup without being aggressive. 

To distinguish between normal and aggressive behavior, you’ll need to watch closely. Of course, the best indication that a dog is actually being aggressive is it hurting the puppy. Obviously, this is what you want to avoid. If the dog seems to be causing the puppy pain, not necessarily injury, it’s reason for concern. Keep in mind that some pups are whiners, and will yep in surprise, even though they aren’t being hurt. 

When it comes to growling, watch your dog when it growls. Are their hackles raised? Do they seem ready to attack? Or are they simply vocalizing their displeasure and issuing a warning? 

Bad Experiences in the Past

If your dog has had bad experiences with puppies i the past, this could explain the aggression. Dogs have excellent associative memory. This means that your dog isn’t likely to remember that a puppy bit them and caused pain, but they are likely to remember that they had a negative experience with a puppy. If they have had a past owner that neglected them in favor of a new puppy or scolded them for setting boundaries with the pup, these can also trigger negative associations. It’s similar to remembering that you don’t like someone, without being able to recall exactly why you dislike them. 

No Experience

A dog that has had no experience with a puppy can be put off by puppy behavior. Puppies have a different personality than adult dogs, and the dog might not know how to interact with the pup. If your dog hasn’t been properly socialized, this can exacerbate the problem. Dogs have their own rules and etiquette, and they learn them from interacting with other dogs. 

Senior Dog

If you have a senior dog, they may have little patience for puppy antics. In the wild, adult and adolescent dogs help care for and play with puppies. Senior dogs have put in their time, and aren’t very involved with puppy training. This instinct remains in domesticated dogs. 

A senior dog, like a senior person, expects their days of caring for youngsters to be over. They are set in their ways and have less tolerance for puppies hyperactivity and neediness. 

Puppy Aggressiveness

Some puppies seem completely unaware that they are at a size and strength disadvantage. They may attempt to be the leader of the pack by being aggressive to older dogs. Most dogs display some patience with puppies, but an overly aggressive pup can easily cause a dog to become aggressive in defense of its status. 

Why is my dog aggressive to my new puppy?

You bring a new pup home, and your dog isn’t as welcoming as you had hoped. Instead, they are aggressive towards the new puppy. It’s a concerning situation, but it helps to understand things from your dog’s point of view. It’s also important to realize that, as the owner, the dog’s behavior is your responsibility. 


A puppy can be a lot to handle, and some dogs have less tolerance than others. If your pup is being too much of a nuisance, your dog may be aggressive because it wants some peace. 

Lack of Pack Leadership

Dogs need a strong leader, particularly when there is more than one in the house. If you aren’t established as the pack leader, the dog and pup may fight for the position. The dog might be aggressive to make sure the puppy knows its place. Be calm and firm with your dogs, and make it clear that you are the one in charge. 

Resource Guarding

Resource guarding usually occurs with other dogs, and not puppies specifically. A dog who is resource guarding will aggressively defend their resources. This can include food and water bowls, their favorite bed, and toys. Resource guarding can also extend to humans. If your dog growls when you go near it’s food bowl or favorite toy, it’s likely resource guarding. 

Resource guarding ranges from slight possessiveness to outright aggression. It’s important to distinguish between a dog that just wants to be left alone while he eats and one that could potentially bite someone it perceives as a threat to its resources. You’ll need to stop the behavior as soon as possible. The more it occurs, the harder it is to remedy. 

Puppies don’t have great impulse control or etiquette Your dog may have a valid issue if the pup is attempting to steal his treasures. You’ll need to teach the pup to not try to steak resources, and your older dog to not be a grump about it. 

The best way to work on both of these things is to give one dog a treat, and then give the other a treat immediately after. This will teach them when one gets something, the other can expect it as well. Over time, this creates a positive association that will make the dogs happy to share and wait their turn. 


Technically, this is considered resource guarding as well, but guarding a person is much different than guarding a food bowl. If your dog is jealous when the pup is in your lap or getting attention, this can cause aggression. Make sure your older dog doesn’t feel left out or neglected. 

If they will tolerate it, try to spend some time petting both of them at the same time. This can help with positive association. You’ll also need to be sure your dog gets some special one-on-one time with you. Just don’t give them attention when they are being aggressive to the pup. Give a stern no and let some time go by, or they will believe you are rewarding their behavior. 

Why is my dog aggressive to its own puppies?

This is one of the most heartbreaking situations you can encounter with dogs. Your dog gives birth and you are sure she will be a wonderful mother. Somewhere along the way, something goes wrong. Your dog is being aggressive to her pups. What happened? 

Pain or Illness in Mother

A mother can become aggressive towards her pups if she is unwell. Mastitis can be very painful and cause your dog to be aggressive, particularly when they want to feed. Mastitis can also make the puppies sick, so a snapping mother could actually be protecting the pups.  Uterine infection can also occur. This can make your dog feel very unwell and requires veterinary treatment. She may lash out at the pups out of pain.

Sick Puppies

Domesticated dogs are not that different from their wild counterparts. They still retain quite a bit of instinct that helped them survive in the wild. In the wild , resources are limited. A mother will reject or even harm a puppy that she believes is too sick to survive. This gives more resources to the puppies that have a better chance of surviving. 

Accidental Harm

Sometimes the problem isn’t intentional aggression. The mother can sit on and smother a pup completely unintentionally. Some dogs seem to have less body awareness and instinct to keep the pups in a safe area. 


Just like humans, dogs become more aggressive when they are under a lot of stress. Giving birth and raising puppies are very taxing. The mother is constantly at the beck and call of her pups for the first few weeks, spending most of her time caring for them. 

If they are too stressed by noise, visitors, or even more puppies than they can handle, they may be aggressive towards the pups. It’s similar to you having a bad day at work, locking your keys in your car, and then yelling at a loved one when you finally get home. 

Lack of Maternal Instinct

Some dogs just seem to lack maternal instinct. It could be a lack of the hormones that promote the bond and protective instinct in mothers, or it could be your dog’s personality. A dog that lacks maternal instinct will reject the puppies. They may avoid the pups and their care, or even be aggressive when the puppies come near. 

How do you get an older dog to accept a new puppy?

You can get an older dog to accept a new puppy. It takes work, patience, and perseverance on your part. 

Start Slow

It can be tempting to just toss the dogs together in an attempt to force them to get along. Sometimes it works out, and there are no problems. However, if the dogs don’t instantly get along, this leaves room for some major issues to develop. Start slow and limit their interaction for the first few days or weeks.


The best way to remedy the problem of resource guarding is to create an environment where there’s nothing to guard. Keep all food, toys, and treats out of the common area. If you want to give them their own toys or treats, give them each a crate or room that belongs to them alone. You may need to feed them in separate rooms until they are accustomed to each other. 

Respect Boundaries

You might think it’s adorable that the pup pulls at the dog’s ear wanting to play, but your dog might not be amused. As the owner, it’s your responsibility to make sure the puppy is not being a nuisance to your older dog. 

Create Positive Interactions

Watch your dogs interact and determine what situation suits them best. Do they seem happy to go on walks together? Do they enjoy playing chase or fetch? Do they like being on either side of you getting pets? Once you’ve discovered a situation that works well for your dogs, use it to create positive interaction. 

What do I do when my old dog hates my new puppy?

It’s a tough situation to be in, but there are things you can do if your old dog seems to hate your new puppy. 

Assess the Situation

Before you make any decisions on a course of action, you’ll need to assess the situation. Is your older dog aggressive at certain times, like meals, or do they growl anytime the puppy gets close to them? The more you can observe about when, where, and why the behavior occurs the easier it is to stop it. 

If It’s Situational

If the dog only hates the puppy interrupting its nap, and doesn’t mind the pup the rest of the time, this is situational. If you can avoid the situations, you’ll avoid the aggression. You may need to separate the dogs at times when aggression is likely to occur. 

If It’s Constant

If it’s constant, you’ll need to separate the dogs immediately. Matters will only get worse if allowed to continue as they are. 

Get Expert Help

If you plan to keep both dogs, it’s a good idea to get some expert help. The situation can quickly become dangerous for your puppy or yourself, so it should be taken seriously. A dog trainer can assess the situation and provide advice on how to proceed. 

Consider Re-homing

If all else fails, you’ll have to re-home one of the dogs. It ‘s best to seek professional help first. You may be amazed by the progress that can be made. It’s not fair for a dog to live in fear. An aggressive dog is also very unhappy. Allowing the situation to continue won’t do anyone any favors.  

How long does it take for an older dog to adjust to a new puppy?

It takes about three weeks in most cases. Following the tips listed earlier can help the process go smoothly and may reduce the time it takes overall. Remember each dog has its own personality. Your dog may adjust within a few days, or it could take a month or more.