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My Older Dog is Aggressive to My New Puppy

I wrote about how I’m feeling overwhelmed with a puppy.

And then I received all these nice comments on how it gets easier and your puppy doesn’t have to be perfect and so on.

Only … my main concern is actually my senior dog Ace!

I’m worried my older dog is being too aggressive with my puppy when resources are involved like his dog bed, toys or … ME.

My adult dog is aggressive to my new puppy

It’s normal for an adult dog to correct a puppy

Don’t get me wrong, it’s totally normal for an older dog to correct a rambunctious puppy. You can bet the older dog will growl or snarl or even lunge if a puppy is being a pest.

This is how a puppy learns it’s rude to jump on a dog’s head while he’s resting, for example.

The older dog shouldn’t be scolded for doing this as long as he’s not physically hurting the puppy.

(Some puppies will yelp and squeal even if they are not hurt. I don’t react to this.)

It’s the owner’s job to re-direct the puppy away from the older dog

The dog owner needs to make sure to re-direct the puppy from being a pest so the older dog doesn’t have to correct the puppy most of the time. Call it a team effort for setting boundaries.

*If you just got a new puppy, download my free puppy training guide. Click Here

Where it gets complicated … resource guarding

My older dog Ace is definitely showing some resource guarding around his bed, toys and, unfortunately, ME.

This is to be expected, to some degree. If a dog is calmly chewing on a bone, he’s going to growl if a puppy barges over to take it. Again, it’s always the owner’s job to manage these interactions.

However, in my opinion, my older dog Ace has crossed a line a couple of times. (And this still falls on me as the owner. Dogs are dogs.)

Older dog attacks new puppy

Should I let my older dog growl at my puppy? Well, in some cases a little growling is good, but my older dog’s aggression to my new puppy is more than what I find acceptable.

One example was when I was sitting on the floor petting Ace and he lunged at my puppy Remy for approaching us.

My older dog is aggressive to my new puppy

Ace used teeth on Remy’s head for a second and left marks (no punctures or scratches). Remy squealed and ran away.

I should have seen this coming and blocked Remy because, let’s be honest, he was BARGING his way onto my lap.

However, I thought Ace’s reaction was out of line.

It left me really stressed out about how I’m going to manage future interactions between my older dog and my puppy.

But on the plus side, Remy is totally fine. He’s happy go lucky and resilient. He likes Ace and he is not afraid of Ace in the slightest. They do have positive interactions with each other every day.

Other notes about Ace:

  • He has been sick for 7 months and has some pain. He’s also had to wear a cone collar which blocks his vision, hearing and movement.
  • I have seen some minor resource guarding from Ace over the years (Behavioral issues are rarely “out of nowhere.”)
  • Since he’s been sick, Ace has shown increased resource guarding around my cat Beamer, so it’s not just the puppy.
My dog Ace with his tennis ball

How to stop your older dog from being aggressive to the new puppy

Here are my recommendations for introducing dogs that will be living together.

In our case, these have helped things go as smoothly as possible for managing two dogs of different “generations.” Update: Unfortunately our senior dog has now passed away but the two dogs did learn to get along just fine!

1. Keep dog intros slow between the older dog and the new puppy.

That goes for the initial meeting but also the next couple of days and weeks. Slowly integrate them into each other’s lives. Don’t force them to play, interact, cuddle, pose for photos, etc.

The two dogs may or may not choose to interact naturally, but don’t force them to be best friends.

See my post: How to introduce your dog to a puppy.

2. Prevention. Prevention.

Pick up all dog toys, bones, Kongs, food bowls, etc. Don’t give them opportunities to fight or guard these items.

It’s wise not to sit on the ground petting one dog if there is any risk of “guarding” like my example with Ace. Use gates, crates and leashes as needed.

*If you just got a new puppy, download my free puppy training guide. Click Here

3. Re-direct the puppy away from your older dog.

The new puppy should not be allowed to bother the older dog. The older dog needs to know you have his back.

My dogs Ace and Remy!

4. Seek out positive experiences between the two dogs.

Do walks go well? Go for lots and lots of walks together as a pack if possible. Bring another adult along to help.

My dog Ace does much better with Remy when we’re outside. He tolerates Remy getting in his face for the most part as long as we’re outside. 

They can walk together, sniff the same bushes, touch noses. I’m using that to create positive interactions. “Yay! Such good boys! Treats for all!”

5. Calmly have both dogs sit and then give them treats.

Dog Behaviorist Dr. Patricia McConnell has an excellent post on dog-to-dog resource guarding.

One idea she listed is to give both dogs treats one after the other for calm behavior. This is assuming you have no tension between the dogs and there is no risk of fighting while they’re sitting there.

In our case this works really well. I use a spoon of peanut butter, have both dogs sit (Remy tethered) and say their names one after the other giving them a few licks rotating back and forth.

It teaches Remy to stay and teaches Ace fun things happen around Remy.

How to get your older dog to accept your puppy

Ace Remy and me

1. Dogs really do live in the moment.

Even if they fight or bite they generally move on from second to second. They can have many positive interactions in any given day.

2. Dogs adapt.

Even if two dogs have had a couple of bad interactions they can move on and live peacefully together if they’re set up for success. Usually anyway. There are exceptions.

3. Humans need to move on too. 

Dog owners have to move on and change their mindsets as well. Even if something bad has occurred, you have to move on.

For example, I need to stay light and positive (not tense). I can’t sit there predicting a reaction from Ace or it’s bound to happen. I may even cause a reaction.

4. It’s not personal.

My older dog is aggressive to my new puppy, but Ace is not capable of “hating” Remy or being upset with me for getting a new dog.

Those are human emotions. My dog is just being a dog, guarding what he feels is valuable and protecting his space. While we can make it complicated, it’s really pretty simple.

*If you just got a new puppy, download my free puppy training guide. Click Here

How long does it take an older dog to get used to a puppy?

It just depends on the dogs. In our case, things got a lot better once our puppy was about 5 months old. At that age, he was large enough where I wasn’t so worried my older dog would hurt him.

And, at that age my puppy seemed to have more common sense and awareness about my older dog’s limits.

My puppy would still push the limits, but he understood there would be consequences such as a ferocious growl or a snap. He knew to “proceed with caution.”

Remy and Ace often cuddled up on the same bed together

I still supervised them, of course, but I wasn’t as worried my puppy would get hurt. Around this time, my older dog seemed to have accepted our puppy and was pretty indifferent to him as long as the pup left him alone.

Then, once my puppy hit about 18 months old, they would even nap together on the same bed.

This was not because they were good friends but because my older dog would be sound asleep and Remy would sneak in for a cuddle. Once Ace woke up with Remy right there, he seemed to tolerate it as long as Remy was calm and quiet.

OK …

What do the rest of you have to add to this?

I love hearing from you! Let me know your experience or concerns in the comments.

*If you just got a new puppy, download my free puppy training guide. Click Here

Older dog is aggressive to my new puppy

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  3. Gentle Leader.
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Other resources:

Lindsay Stordahl is the founder of That Mutt. She writes about dog training, dog exercise and feeding a healthy raw diet.


Monday 7th of March 2022

I have a 4 year old German shepherd/Alaskan malamute/French mastiff mix who is not dog or people friendly. The people problem his vet thinks is general anxiety as he calms down fine with a treat or some play, but his dog issues are caused by bad past experiences. When I got him I was in an area without a lot of dogs and I was only 16 and unable to take him to parks, and to be honest, just didn't really think about it because I have another dog for him to socialise with. But outside of him, the only other times he has met dogs (my brother and my cousins dogs) has ended with them attacking him and having to be pried off his neck. Not exactly encouraging. My housemate recently got a very small/underweight staffy puppy and while my dog seems curious for the most part, he is also very attached to my housemate so when he sees the puppy being held or sitting on his owners lap, he starts growling and barking, and I've had to hold his collar to stop him from possibly lunging. My dog is almost large enough to be classed as a giant breed, and the puppy at 2 months old is still only about 20 to 30 centimetres long (it was a very large litter and he was very underweight when we picked him up), so my biggest concern is that a poor interaction with have deadly consequences...

Lindsay Stordahl

Monday 7th of March 2022

Yes, you will have to be very careful, especially while the puppy is so small. I would consider a basket muzzle for your big guy. Get him used to it away from the puppy, first, using positive associations. Then you can have him wear it around the puppy to give you some peace of mind while you work on getting them used to each other. Walking them together is usually what works best for me, so they can be focused on sniffing and moving forward rather than each other. I would recommend you work with a trainer in your area in order to keep everyone safe. Good luck with the puppy.


Monday 6th of December 2021

We just brought home a 7-week old British lab. We have an almost 2 year old lab. The older dog is showing food aggression and has bit at our puppy three times the last two days. Two of the times nothing was involved (toys, food, or us) We started feeding separately and keeping them away from each other as much as we can. Is there anything else that helps? Will it pull them further apart keeping them separated? I’m just scared she is going to hurt the tiny puppy and don’t understand what is causing it. Seems the aggression started after her first heat (she is spayed now). We had a 11 year old lab when she was a puppy that was an absolute sweetheart and passed away before we brought the new puppy home, she is the only adult dog in the house. Thank you


Friday 8th of October 2021

We have a 13 year old Maltese(Jack),a 2 year old chihuahua(Ernie) and we have a 13 week chihuahua(Dudley) also. Our 2 year old is attacking him whenever he gets a chance:( It is awful and the baby is only 2 lbs. He growls whenever he is near and the first attack he bit him and threw him.He would have continued this if I hadn't been right there:( I've tried all of your suggestions above and the baby doesn't even try and play or nip at Ernie. Ernie seeks Dudley out and this is a daily thing:( If I can try anything else I am open to suggestions:)


Sunday 26th of September 2021

Just want to say I enjoyed this article and the info. I have an 8 year-old Doberman, who very much sounds like Ace with my 4-month-old Dobie puppy. Your article spoke to me in so many different ways. Thank you. My condolences for the passing of Ace.

Heather V

Thursday 22nd of July 2021

Great article and tips!! We are in the midst of this nightmare…I mean lovely event….right now. We’ve been trying to take it slow and give treats for calm behavior. We are going to implement the tandem walks with treats immediately! Our 4 year old dog has bitten the puppy on the foot after a gate was accidentally left open and the older dog went looking for trouble with the puppy. Not sure what would have happened if my daughter hadn’t broken up the fight. Please tell me this is normal and will be okay.

Lindsay Stordahl

Thursday 22nd of July 2021

I would just keep things slow and get help from a local trainer if your adult dog seems to be seeking out trouble. It's definitely normal for them to get feisty when the puppy approaches them or another resource (like a person). I would be a little more leery if the adult dog is going up to the puppy to cause trouble. But take things slowly and hopefully it will all get better.

Heather V

Thursday 22nd of July 2021

PS. I’m so sorry about your loss