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Puppy fear periods can be extremely unnerving for both dog owners and puppies, but thankfully, this fear stage does not last forever.

If you have found yourself saying “Help, my 3-month-old puppy is scared of everything!”  Or “I don’t know what happened, my 4-month-old puppy used to be so outgoing!”

Mastiff Puppy Puppy Fear Periods - 1
© 2020 Big Dog Mom, LLC

You have come to the right place.

In this post, you will learn:

  • What fear stages in dogs are and how to know if your puppy is going through one,
  • Common mistakes made during puppy socialization and how to avoid them,
  • Why bringing a puppy home before 10 weeks old is NOT recommended, and
  • the top 5 things you need to know about fear periods in dogs.

Let’s get started…

Attack of the Vacuum Cleaner

3 Month Old Puppy Scared of Everything Fear Stages in Dogs

It started out like every other day.  Wake up, feed kids, feed dogs, and attempt to make myself presentable.  

At about 10 am that morning I ventured on a walk with Junior, then 8 months old.

Junior was as sweet and outgoing as you could ask a Mastiff puppy to be at that age.  Knew no foe. Was unafraid of anyone or anything.

He was at times, in fact, too friendly for his own good.  Like the time he met two “oh yes, my dogs are very friendly” chihuahuas.  These sharks in chi-clothing resented Junior’s kind, gentle approach and responded with a fury of bug eyes and tiny teeth.

But even the chi-attack was brushed off as a minor insult. Junior’s temperament was bombproof.  

Until the day it wasn’t…

What are Fear Periods in Dogs?

There are times in every dog’s life when their world is turned upside down.  When even the smallest of events becomes a monumental obstacle. Stages of development when puppies are hyper-aware of the world around them and learn to respond with a survival instinct like their wolf ancestors.

These periods of development are referred to as puppy fear periods or the puppy fear stage as others call it.

During certain fear periods, the reactivity level of puppies rises causing them to act defensively, become protective, and more territorial. These new fears seem to pop out of nowhere.

Dogs appear fearful of novel stimuli or stimuli met before but that did not trigger a significant reaction.  

Pam Dennison states in You Can Train Your Dog,

“One day he’ll be fine with something or someone, and the next day he’ll be terrified…. These are normal growth behaviors in young dogs as they mature.”

While some of these fear periods go unnoticed by dog owners, in other cases owners are left scratching their heads, or worse, responding.

When Do Fear Stages in Dogs Occur?

The timing of fear periods are given in ranges, however, when they occur in an individual puppy it is as defined as the day they were born.

Consider what Dr. Jen states in The Dark Side of Socialization: Fear Periods and Single Event Learning,

“The dangerous part is this: during this particular developmental stage, your dog’s brain is on a hair trigger, exquisitely sensitive to anything “bad” that may happen.  A single frightening or painful experience during the fear period can have a lasting impact for the rest of your dog’s life.”

Fear Imprint Period (or Critical Period) (8-10 weeks; range 7-11 weeks):

This is not a separate stage of development but a component of the Socialization Stage which starts at 3 weeks old.

This period of development is so important to the development of social skills and to the dog’s understanding of the world around him. It represents the time when a dog’s potential as a companion animal is either fostered and nurtured or impeded and even destroyed.  

If subjected to physical or psychological trauma during this time, a dog is most likely to develop an avoidance response. It is also within this stage that at least 50% [READ: Nature Versus Nurture and the Drivers of Canine Temperament] of the dog’s eventual temperament is developed. During this time, a puppy is very sensitive to traumatic experiences and a single scary event may be enough to traumatize the puppy and have life-long effects on his future behaviors.

Coincidently, this fear period in puppies coincides with the time when they are commonly separated from their dam and littermates and are sent to new homes.  

More on this in a minute.

Adolescent Fear Period (12 weeks – 6 months):

Puppies are now autonomous but are still learning about the world around them.  

Many will go through a fearful time when they begin teething between four and five months of age. This is often considered the 5-month-old puppy fear stage.

Noticeable changes in puppy behavior can occur as early as 12 weeks when an owner will lament that their 3-month-old puppy is suddenly scared of everything.

Flight Instinct Fear Period (Approximately 6-9 Months (range 6-14 months):  

One of the most critical times in a dog’s life, and arguably one of the most challenging, is between the ages of 6-9 months.

Owners may suddenly and out of nowhere notice their 6-month-old puppy scared of strangers or a 6-month-old puppy “scared of everything” as they scramble to figure out why.

This phase is sometimes referred to as “teenage flakiness.” Adolescent dogs may spook at the silliest things. You walk down the same street every day for months and one day, out of the blue, he becomes hysterical at the sight of a fire hydrant that has always been there.

Your pup may become unable to enter his own backyard because there’s a wheelbarrow parked in the corner that wasn’t there before. Environmental contrast. They are on high alert when they perceive things aren’t “normal.”

Adult Fear Period (Approximately 12 – 18 Months):  

Fear periods in dogs continue past the one-year mark for many dogs and puppies as they are still developing and maturing.

This particular puppy fear stage is believed to be related to the surge in growth that occurs at this age which may cause some physical discomfort. Sexual hormones surge now, too, which can cause mood changes and as a result, fearfulness. This fear period tends to happen between twelve to fourteen months of age.

Attack of the Vacuum Cleaner (cont.)

Puppy Fear Periods - Fear Stages in Dogs

So Junior and I were on our walk.  We rounded the corner and, about the same time, noticed a group of men in a neighbor’s front yard doing some landscaping.  A couple of the men had hats on, one had a loud leaf blower, and a third was dragging a huge trash can and rake. Junior had seen similar men in our neighborhood countless times before, had heard leaf blowers, seen hatted men, and said hello every chance he got.  This was a familiar scene with friendly strangers.

But on this day, at 8 months old, like a light switch was turned off, Junior didn’t recognize his “friends” anymore.  They were strangers. Foes?

Junior stiffened as soon as he saw them, hair along his back on end, and, to my shock and horror, let out an imperceptible growl under his breath.

At that moment, with PTSD activated from my heartbreaking days with Linus, I tried to keep walking.  But of course, the men were enamored with Junior and couldn’t help but talk to me as we tried to pass…

Later that night, I got the vacuum cleaner out and, while I finished up other tasks, left it sitting in the hall.

Junior came into the hall, took one look at the “intruder” and did the same thing.  Stiff, hair on end, low growl. He didn’t look to me for assurance, as perhaps he might have done before.  He walked stiffly, intently, toward his new enemy….

How to Know if Your Puppy is Going Through a Fear Stage

In early fear periods, you may not notice any change in behavior.  However, as the puppy ages and enters later stages of development, reactivity levels rise causing them to act defensively, and become protective and more territorial.  

Like with Junior, these new fears seem to pop up out of nowhere. And can be directed toward novel (new) stimuli or stimuli met before with no reaction.

Whether it’s a 3-month-old puppy suddenly scared of everything or an otherwise outgoing 6-month-old puppy scared of strangers whom they have decided are a threat that must be protected against.

During these stages, puppies may show fear of items, situations, or people with whom they formerly felt safe. They may start barking at people entering a house or become fearful and startle at benign items like trash cans, drain pipes, or even Dyson vacuum cleaners.

They may crouch, shake and try to run away, submissively urinate or, tell the scary thing/person to go away by showing an aggressive display, which may include snarling, lunging, or other unruly behavior.

Interestingly, dogs whose genetic heritage has programmed them to be alert and focused outward will often have a more pronounced fear period. Protection breeds (Shepherds, Rottweilers, Doberman pinschers) and herding breeds (collies, cattle dogs) will need increased positive socialization during adolescence.

Here’s the important point.  

The behavior that gets practiced, and is discovered to be effective, gets reinforced.

When he suddenly notices the neighbor across the street getting out of his car, or the landscaper in the distance with a leaf blower, and sounds the increasingly high-pitched alarm.  Be mindful that as those men go about their business and walk away, your puppy’s confidence is emboldened as he effectively “scared away the bad man” (who was leaving anyway).

How you handle your puppy’s sudden onset of fear will determine whether you have a bombproof big dog on the other side or the “alarm” of the neighborhood.

Read the following posts for essential tips on raising and training your puppy the right way:

5 Tips For Helping Your Puppy Conquer Fear

1. Remain calm

No matter how embarrassing the behavior, it is critical that you do not overreact in response to your dog. 

Control their environment so they don’t feel they have to defend themselves. Keep in mind that this behavior is not a sign that your puppy has turned aggressive.  But rather he is unsure and needs to overcome his fear at his own pace.

You must be patient during these periods and keep to a familiar routine.

2. Pretend it’s no big deal

Control situations so that you can prevent a fearful response and show your puppy that you enjoy the situation.

Use food treats and happy talk to encourage your puppy up to scary objects.  I have found touching the object myself, and then encouraging my puppy to touch it with a happy, nonchalant attitude, is the best approach.

Never drag or force interaction with a scary object.

3. Don’t overwhelm, Desensitize!    

Never force your puppy to interact with the feared object or person.  

A 6-month-old puppy scared of strangers is not going to be convinced a stranger is friendly by force. That would be like me trying to convince you taxes are good by taking away all your money.

A better approach is to allow your puppy to investigate whatever he fears on his own and praise/reward any initiative he or she takes.

Pam Dennison recommends,

“It is vital that you don’t laugh at, scold, or comfort the dog during this time…. Ignore and wait for calm behaviors that you can then reinforce.”

4. Socialize, socialize, socialize

Mastiff Puppy - Puppy Fear Periods - Puppy Socialization
© 2020 Big Dog Mom, LLC

This one is a balancing act during a puppy fear period.  

Keep in mind that the most significant opportunity window to solidify a bombproof temperament closes at 16 weeks (4 months).

While it is essential to continue socialization throughout your dog’s life, you want to make the absolute most of this time.  

The key is to avoid exposing your puppy to traumatic experiences.

Shipping the puppy or allowing the puppy to undergo elective surgeries (like spay and neuter) at this time is not recommended.

Veterinarian visits and car visits should be made fun and upbeat. Things like vaccines, cold examination tables, taking rectal temperatures, placing the puppy on a scale, nail trims, and being handled by strangers, are all experiences that you want to make sure you are doing, but not right in the middle of a fear period if they can be avoided.

Do not encourage “watchdog” behavior at this age.  These only reward fear and suspicion, not bravery, and confidence.

5. NEVER punish the fear

Punishing fear will only exacerbate it and potentially solidify it.  

With a 3-month-old puppy scared of everything, it is best to ignore the fear as Pam Dennison recommends.

Let your dog build confidence by letting him investigate things on his own when he is ready and praising him for the effort.

Use force-free behavior modification such as desensitization and counterconditioning.

How to Take the Fear out of Puppy Fear Periods

Here are a few helpful tips you can use with your puppy during a fear period to ensure you make it through unscathed.

  1. Use treats consistently and liberally to make positive associations!  Food naturally has meaning to your dog, so when it is paired with things that have a negative meaning (i.e. the scary vacuum cleaner), the negative association is lessened or eliminated.
  2. In the comfort of your home, perform “pretend” vet visits with fake vaccines (a pen), mock examinations, and known people pretending to be friendly strangers. Use treats liberally for this fun exercise.
  3. When people visit your home during these periods, put your puppy in another room until visitors are settled in, then bring your puppy out on a leash and praise him or her for any show of confidence. Have visitors toss good treats toward your puppy without approaching him or her.  Do not force, punish or coddle your puppy if he exhibits fear.
  4. Do not overdose your puppy with scary loud noises and exposures during his fear periods.  Things like vacuuming can still be accomplished, but just do it one room at a time while your pup is 8 to 10 weeks old. Then stop and leave the ‘vacuum monster’ out where your puppy can investigate it between ‘roars.’  Use treats liberally.
  5. Always make going “bye-bye” in the car fun!  Use treats liberally while getting in and out and when meeting friendly strangers.
  6. Consider using a DAP diffuser like Adaptil, plugged in at home when you bring your puppy home for the first time.
  7. Make crate-training fun with toys and treats.

For more ideas on things you can do with your puppy prior to 16 weeks, read:

Puppy Fear Periods: 5 Simple Tips That Can Save Your Puppy! Puppy fear periods can be extremely unnerving for both dog owners and puppies, but thankfully, this fear stage does not last forever.

Adaptil Diffuser

Shown to be an effective and drug-free solution tohelp calm and relax your dog at home and reduce common signs of stress.

Optimal Time to Bring a New Puppy Home

In preparation for this post, I reached out to the Big Dog Mom Community to find out what age their puppy was when they acquired him.  

In a poll of 69 respondents that brought their puppy home before 6 months old, 48% said their puppy was either 5 – 7 weeks or between 8-10 weeks old.  And we can bump that up to 49% when I add Sulley to that list as well since I flew him home at 8 weeks old. I picked up Junior at 10-11 weeks old.

Here’s why this is important.  

The Fear Imprint Period (or Critical Period) occurs at 8 – 10 weeks old.  And unfortunately, this is the time most puppies are separated from their mom and littermates and are sent to new homes.  

There is increasing evidence that suggests it is better for puppies to remain in the breeder’s home with the dam and littermates until AFTER the Fear Imprint Period to avoid anything that could be interpreted by the puppy as traumatic or scary.

Everything about the experience of traveling to a new home can cause fear in a puppy, so avoiding those things during this fear stage is important.

The longer a puppy gets to stay with his dam, the more time he has to develop traits and good habits that will help him in the short and long term.  

By the time a puppy is 10 – 12 weeks old, he will have been accustomed to feeding and grooming himself. He will have learned to socialize with other dogs, and the dog’s personality would have had some time to develop.

And lastly, consider that most of the social rules are taught and reinforced by mother dogs during weeks 6 through 8. The consequences of removing puppies from their littermates and mothers even earlier than 8 weeks are both far-reaching and impactful.

Stay tuned to Big Dog Mom™ for more on puppy development prior to 8 weeks.

For now, please consider waiting to bring your new puppy home until he is 10 – 12 weeks old.  

I know how excited you are.  But, remember, good things come to those who are patient.


The latest on Youtube:

…The Rest of the Story

Had the landscapers ignored us, perhaps we could have just walked on past without incident. That wasn’t in the cards for me that day.

“He’s BIG!  Is he friendly?”  

Me, (thinking, usually….though now I’m not so sure) “Yes, he’s friendly.”

With Junior in the lead, we proceeded toward the men in hats, with rakes, and loud tools. Slowly. Intently. Hair still on end. Tail slightly curled under.

Over the next two minutes, Junior dutifully sniffed each man and each tool.  There was no tail wag or wiggling puppy butt. He was a “man-dog” with a mission.  Learning about his world as though it was his first day in it.

The men, oblivious to Junior’s body screaming at them, asked all the usual questions about Mastiffs.  While making small talk, I let Junior inspect at his own pace, watching every lip lick, every eye flicker, tail set, stiff body.  

I was having flashbacks at that moment. PTSD of a human-aggressive Mastiff surrounded by foes.

We walked away without incident.  A week later, we came across the same men, the same neighbor, the same corner.  Junior’s puppy wiggle was back! Whew!

And for those of you dying to know how the Dyson faired… well, it survived too.

Junior stiffly and courageously approached but didn’t sniff it until I tapped the Dyson and declared, “See, it’s the vacuum cleaner.  No worries.”

From agitation to curiosity, he made friends once again with the vacuum cleaner.  

And fortunately for Big Dog Mom, sweeping has never been easier with these two BFFs.  Simply turning on this momentary foe is now an invitation to follow me around the house and lay in my path.

Puppy fear periods are funny things.  

They come and go like the wind when handled properly, but can have a lasting effect when they aren’t.

Share this post with a friend.   

Let’s make an impact together, creating one bomb-proof big dog at a time.

Great Resources and Information About Puppy Fear Periods

By Nancy Frensley, CAP2, CPDT Behavior & Training Manager Berkeley-East Bay Humane Society

Critical Periods in Puppy Development

The Dark Side of Socialization: Fear Periods and Single Event Learning

Puppies Taken from Litter Too Soon Develop Behavior Problems as Adults by Karen Becker, DVM

What Is the Best Age to Send Puppies to Their New Homes?

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  1. This was a very interesting read thank you! I just adopted a 5 month puppy who came from an organisation where he lived in perfect harmony with many other dogs. A few days in and he has started to fear other dogs and is aggressively growling, snarling, and barking. If I stroke him during it he tries to bite me… but outside of this he is very affectionate and never aggressive.

  2. Exactly the information I was looking for! My 5.5 month Bernedoodle is afraid of his own shadow! He jumps at every noise, every stranger, every moving object – especially when he’s tired. He growls, walks toward the scary thing, and tells it to go away. I have tried treats galore (he won’t touch them in the presence of strangers), naps or walks before meeting someone new, soothing and firm voices, ignoring him, and even hemp treats! His fear only seems to get worse with age. I’ve been looking for an article like this to help me understand where his fears came from and what I can do to quell them. Though I feel I’ve exhausted most of my options, I’m hopeful with more exposure, age and neutering he will settle down and return to being the carefree puppy I brought home!

  3. I’m so glad to have found your site! We are fostering a 5 month Pyr, so we have no idea what happened during those fear windows – we might have our work cut out for us, but your articles have already been extremely helpful.

    If I could make one suggestion for this article, it’s that you remove the two places where you say “in broken English” – it isn’t relevant to the story.

  4. I have a curly coated retriever. She is/was a successful conformation showdog. She has now just turned 11 months old. She suddenly and without reason has developed a fear of the judges touching her. She backs away and tries to run out of the showring. If a judge cannot touch her she is disqualified. We have exhausted male, female, beard, hat on etc -all to no common factor with the variety of judges.. She has been disqualified the last 7 shows (2 months). She is displaying a severe fear factor and I am very concerned for her.

    She is over aware environmentally but it is dealt with, fortunately, just like your article says. She gets on well with all other dogs. But as soon as she enters that ring, she moves beautifully she is frightened of the judges when they walk towards her, even with different handlers, the result is the same.

    She is a the only dog at home. She is in a crate travelling inside in the car and whilst at the shows. At home she doesnt chose to sleep in one but has a secure dark covered one available to use if she chooses. Otherwise she sleeps on couches, her beds or in a bedroom. She is a much adored family pet and lives with 2 cats and a family. Any advice?

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