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Meet Your Adolescent Newfie Puppy

The most challenging time of raising a Newfie puppy is definitely the adolescent stage. 

That’s not to say that the puppy stage and senior stage isn’t challenging because potty training and senior Newfie issues are definitely not easy, but teenage Newfies should be a breed on their own. 

So, as we all know, every puppy will go through an adolescent stage where they transition from a cute little fluffball to an unruly teenager. 

But with a Newfie it seems like this stage is 20 times harder than with any other puppy due to their fast growth spurts and large size. 

We’re not dealing with a 25 pound puppy, we’re dealing with an unruly and hyper 60-100 pound puppy which makes their actions even bigger. 

The period when a Newfie reaches the adolescent stage will vary from dog to dog but the majority of them hit it around 6 months and it can last well into their 3rd birthday. 

With other puppy breeds, you usually see the adolescent stage last until their about 18 months but since large breed dogs tend to mature at a slower rate, some Newfies may drag their feet reaching maturity. 

6 month old brown newfie puppy chewing

Lou is starting with this stage and I think he hit it a little early but maybe that means it’ll end a few weeks shy of his 3rd birthday then. (hahaha)

Adolescence doesn’t happen overnight, in fact, it slowly starts to build up and the signs can be so subtle that you might have missed them.

Even though I’ve covered this stage in one of my most popular posts, The 4 Stages of the Newfoundland Dog, I think this stage deserves a more detailed post.

This is the stage where many adolescent Newfies are relinquished to rescues or shelters because their owners weren’t expecting this stage to happen. 

Every puppy goes through this stage and the Newfie is no different it’s just amplified more because they are bigger and grow faster than the average puppy.

Before we get to some common behaviors that you might see at this stage I want to say that this is in no way saying that Newfies are bad.

It’s quite the opposite actually because they are an amazing breed but they do have their moments when they’re growing up. 

Now, you may have or had a Newfie puppy that didn’t go through this phase and that is awesome but I can assure you that is not always the case. 

In fact the reason for this post is to bring to light some behaviors that new Newfie owners may not expect.

I would rather have someone new to the breed be over prepared then under prepared and overwhelmed. 

9 month black newfoundland puppy

Common Behaviors and Characteristics of an Adolescent Newfie

Almost all of the behaviors and characteristics listed below of an adolescent Newfie can be seen in any breed of puppy:

  • Unwanted chewing (furniture, remotes, shoes, baseboards…etc .)
  • Zoomies-running around like a maniac and having bursts of energy
  • Humping humans, other dogs, other objects
  • Potty Accidents
  • Urine marking inside the home
  • Displaying aggressive behavior towards people or other dogs
  • Resource guarding
  • Jumping
  • Lack of respect and response
  • Selective hearing 
  • Counter surfing
  • Challenging their humans
  • Destruction
  • Mouthing
  • Selective eating

Unwanted Chewing

This is usually carrying over from puppy chewing due to teething but many Newfie puppies will have their adult teeth at this age and the chewing starts to get destructive. 

They will chew on everything and everything. 

A lot of Newfies seem to like to chew on baseboards, wooden chairs and remotes but they aren’t very selective and will chew on anything they can get their big mouths on. 

Make sure that you’re giving your Newfie plenty of appropriate items to chew on.

brown newfie puppy with chew toy

Frozen Kongs or Toppls are a great option and you can also speak to your veterinarian or breeder for other ideas. 

Make sure to give them a variety of options and switch them up to keep them interested. 

And if your Newfie likes to chew, don’t leave them unsupervised. 


When an adolescent Newfie puppy gets the zoomies it’s hard not to laugh. 

When Lou gets the zoomies he reminds me of Tigger.

He’s very bouncy and just bounces on or from one thing to the next. 

He tries to bounce onto the counters and it never ends well for him.

On one hand, his bounces look very light and fun but they are also very uncoordinated and unpredictable. 


Humping is normal puppy behavior and can be due to hormones when they’re a teenager. 

Sometimes the puppy humps its owner’s leg and with a Newfie puppy, they hump their owner’s entire body. 

It’s hormonal now but it should be corrected so that it doesn’t turn into unwanted or learned behavior later. 

Neutering your dog may not take care of this.

I had a neutered Beagle and he humped his entire 15 years on this planet.

adolescent stage of newfoundland

Potty Accidents

Some Newfies are potty trained by 6 months and some aren’t. 

The ones that are may revert back to being not. 

Well, it’s not that they aren’t, they just forgot or sometimes it’s because of those male hormones.

Urine Marking

Marking is your dog’s way of saying, “this is mine” and it’s a natural thing that dogs do. 

Male and female dogs mark but it’s more commonly seen in male dogs.

Dogs mark their territory inside and outside and they can be random spots or their favorite spot.

Dogs usually mark for two reasons; territory and anxiety so it’s always a good thing to monitor your dog and see when and where they’re marking the most. 

Aggressive Behavior

Puppies can have different types of aggression when they’re growing up.

Some of these aggressions are normal and some should be dealt with immediately before they become a bigger issue. 

Puppies growl and a Newfie puppy growling is totally normal, especially if it’s when they are playing with other dogs in the home or family members.

Play aggression is like bitey face.

Your dog is growling and opening its mouth at another dog but not actually biting. 

This is normal play behavior and if you don’t want them doing it, correct the behavior when it starts.

Lunging, snapping, and biting are aggression issues that should be addressed by a professional dog trainer. 

Always remember that your Newfie is a dog first and a Newfoundland second. 

That gentle giant that you’re desperately searching for takes time to develop and mature. 

Resource Guarding

Resource guarding can be seen in any breed of dog but people are surprised to see a Newfie doing it. 

Sherman used to resource guard his toys and me.

Finn guards his toys and I noticed Lou did this one time last week with a toy. 

lou the brown newfie puppy

I’ve really been working hard with Finn on this and he’s gotten a lot better except when things are escalating. 

I’m not too worried about Lou because it was just small growl to tell Finn to back off, I didn’t have to intervene and it hasn’t happened again. 

With Sherman’s resource guarding I did have to consult with a professional dog trainer because he was actually fighting with Leroy.


Another normal puppy behavior but magnified in the Newfie breed because they are bigger. 

This is a crucial behavior to correct especially if you have young children in the home. 

Newfie puppies love to play and they often see young children as their playmates so it’s super important to teach both the Newfie and the child how to act around each other. 

Check out this post from The Preventative Vet called teaching Your Dog To Stop Jumping

Selective Hearing

Selective hearing is a common trait in Newfies and it has nothing to do with them being bad and everything to do with them being smart. 

Unless they have a serious hearing issue, they CAN hear you but they want to know what’s in it for them. 

For example, when you tell them to “come” and they don’t. 

brown newfoundland puppy confused

They might look at you and they might not  and what they really want to know is. “what’s in it for me if I do come?”

Like in the middle of winter and they’re laying out in the yard but you want them to come in. 

They are perfectly content out there and they probably really don’t want to come inside the house with the furnace blasting. 

What’s in it for them if they sacrifice the snow for a toasty warm house?

A treat? Belly rubs? A steak?


Counter Surfing

Newfies are curious just like any puppy but the difference is that Newfs are big and they can reach areas that other puppies can not. 

They don’t have to steal things off the coffee table because there are better things on the kitchen counter. 

I’ve never had a true counter surfer until Lou. 

Thankfully, at this moment in time, he doesn’t just help himself to things on the counter but he is VERY curious when I’m at the counter preparing meals or getting treats.

At this moment in time, I haven’t had to resort to any outside counter surfing interventions but if you need some, check out this post on counter surfing

Challenging Their Humans

We are here and while I know this isn’t the most appropriate reaction, it makes me laugh sometimes when Lou challenges me.

He growled at me the other day when I went to take an acorn out of his mouth and I stepped back and gave him the death glare. 

He looked at me for a quick second and then looked at the ground.

I think he knew he failed that “test.”

So yes, they will test you to see how far they can go. 


Destruction of property is unintentional and intentional. 

Newfies aren’t always the most graceful creatures when they’re shuffling through the house. 


Things get knocked over with their happy tail and exuberant paws.

They put a lot of wear and tear into their homes and between 6months – 2 years of age your home may take a beating. 

Rough Play

Sometimes I think that Lou knowns he’s bigger than Finn but sometimes he forgets. 

I don’t think that he ever intends to hurt Finn but sometimes their play gets a little rough and I have to step in.

With Newfoundland puppies, I think it’s a constant adjustment because they grow quickly and they have to keep adjusting their playing habits with other dogs in the home.

adolescent newfie puppy 

It’s just important to always monitor your puppy when they’re playing with smaller dogs in your home. 

Finn’s a tough little cookie but right now, Lou is double Finn’s weight and that can cause injuries. 


Puppy mouthing is normal puppy behavior but I feel like some Newfies are VERY mouthy. 

Young puppies are normally bitey and nippy. 

They bite at your hands and legs and their razor sharp puppy teeth hurt like heck. 

As they get older the nipping tends to turn to mouthing and many Newfies will mouth your arm or hands when they’re excited. 

It’s kind of like your arm is corn cob and they will nibble at it-puppies may bite but not in an aggressive way. 

All of my Newfies have been mouthy except for Leroy.

Lou is very mouthy especially when I come home. 

I’ve been redirecting him with a bucket because he also loves to carry things when he’s excited. 

Obviously I don’t always have a bucket on me but I do have several scattered across the house and one by the door at all times so I can easily give it to him.

He also likes to try and help me with grocery bags and when I say “help” I mean he tries to rip the bag out of my hand and smash it.

Selective Eating

Some Newfies (mostly males) will go through a stage where they don’t seem interested in their food.

Many times this is due to hormones or being bored with their food. 

Don’t forget that they’re a working breed so if your Newfie doesn’t seem interested in eating and medical conditions have been ruled out, you can try to feed them in a different way. 

You can try a puzzle toy, a Kong or Toppl, or a treat dispensing toy. 

Set Backs

There is probably going to come a time during this stage that you feel like you’re taking 2 steps forward and 4 steps back. 

Set backs will happen and it will seem like your puppy has forgotten everything. 

Sometimes it’s potty training, sometimes it’s basic commands. 

It’s just a phase. 

Tips For Getting Through The Teenage Newfie Stage

Don’t confuse your Newfie puppy’s hormonal behavior with them being a bad dog. 

They need your help and guidance to get through this, so don’t give up.

Keep training in short sessions and stay focused and positive and make sure that everyone in your home is on the same training page as you. 

If you’re struggling with your Newfie being mouthy, instead of trying to train out this behavior train them to use their mouth correctly. 

Most likely there will come a day pretty soon that your puppy will forget everything you’ve taught them up until now. 

He didn’t forget, he just can’t access the information in his brain as easily.

Go back to basics and help him locate it. 

Pay close attention to your puppy’s behavior, any signs of serious resource guarding or aggression should be dealt with immediately and not put on the back burner. 

If you’re at your wit’s end, reach out to your veterinarian, dog trainer or breeder.

At 6 months, Lou and I are just entering into the adolescent stage.

We’ve got mouthing, rough play, jumping, counter surfing, minor resource guarding, rough play, selective hearing and destruction. 

We’re working on all of it and taking it one day at a time. 

Lou is not a bad dog by any means, he’s a puppy being a puppy

It’s a sad truth that most Newfies are put up for re-homing during the teenage phase over any other time during their life.

Don’t give up on your Newfies during this stage.

Stay the course. 

With training, reinforcement and practice you will soon have the adult Newfie dog you always dreamed of, Newfie promise!

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Friday 12th of January 2024

I’m on my second Newfie and I agree. The first three years are definitely an experience. I first thought he was a little windy between the ears but grew out of that. Now as my second one is a year old I know that for a lack of better words they are a “ special kinda stupid “ until they grow up and like turning on the lights you will wake up one morning to the best dog you’re ever going to own

Amy Eccleston

Thursday 30th of December 2021

Ah. Your post gives me hope that we will get there eventually with our very challenging 15 month old. All of the teenage behaviour plus now attention barking (which we are ignoring). X


Tuesday 28th of September 2021

Excellent post! Makes us teenage parents not feel so alone. Thank you!


Tuesday 28th of September 2021

Thanks so much Michelle. I remember when I had Leroy and I thought for sure that I had a defective Newf! Lol

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