Understanding Fear Periods in Dogs

Updated on March 6, 2019
alexadry profile image

Adrienne is a certified dog trainer and behavior consultant, former veterinarian assistant, and author of "Brain Training for Dogs."

I am so scared! Dog fear period explained.
I am so scared! Dog fear period explained. | Source

Dog Developmental Stages: What Are Fear Periods in Dogs?

Why is Rover suddenly scared of strangers? This is often a question I get from dog owners who have pretty much owned a dog who cared less about being approached by a friendly stranger and now is cowering between the owner's legs. As I attempt to assess the situation and ask several questions, I place a strong emphasis on the dog's age. Why is that? Not many dog owners are aware of the fact that dogs undergo fear periods during their developmental stages. During these distinct periods dogs may gradually become more and more fearful of situations they once appeared to be accepting of. The fear may be manifested by overly cautious behaviors, where the puppy or dog approaches people or items tentatively or defensive behaviors involving barking/lunging/growling. In some cases, dogs may act bold towards certain stimuli and uncertain with others. However, it is important to note that dogs can become fearful of specific things at any age and no generalizations can be made. Let's take a look at these fear periods and see how they affect man's best friend.

First Fear Imprint Period: 8-10 Weeks

According to Meghan E. Herron, veterinarian and Diplomate of the American College of Veterinary Behaviorists, this first fear period takes place between the ages of 8 to 10 weeks. During this time, the 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. The fear can be of a person, dog or object. A fear period is therefore a stage during which the puppy or dog may be more apt to perceive certain stimuli threatening.

In nature, during this time, puppies are getting out of the den and starting to explore the world around them. This is when puppies would learn under the guidance of their mom, which stimuli are threatening and non-threatening for the purpose of survival.At this stage, once they are fully mobile and outdoors, a lack of caution may cause them to easily get killed, explains Certified Applied Animal Behaviorist Patricia McConnell, in her book "For the Love of a Dog".

Coincidentally, in a domestic setting, this fear period coincides with the time most puppies are separated from their litter mates and moms and are sent to new homes. Some breeders feel that their puppies are better off adopted at a later age. This is why some decide to sell puppies at 12 weeks.

During the first fear period therefore it is important to avoid exposing the puppy to traumatic experiences. Shipping the puppy or allowing the puppy to undergo elective surgeries at this time is not recommended. Veterinarian visits and car visits should be made fun and upbeat. Stimuli and experiences puppies may find as frightening include but are not limited to: vaccines, cold examination tables, taking rectal temperatures, placing puppy on scale, nail trims and being handled by strangers.

How to Make Things Better

  • Use food to make positive associations!
  • Have volunteers participate in "mock vet examinations" and use treats
  • Practice giving "fake vaccinations" with a pen and use treats (for more on this read how to make dog less fearful of shots)
  • Make car rides fun!
  • Have a DAP diffuser plugged in at home when you bring your puppy home for the first time.
  • Make crate-training fun with toys and treats.

Second Fear Period: 6 to 14 Months

While the 8 to 12 week puppy fear period is in some cases hardly noticed by puppy owners, the second fear period appears to have a much bigger impact. Rover has grown now and if he is a large breed he may even weigh 100 pounds or more! This fear period is believed to be tied to the dog's sexual maturity and growth spurts. This means that in large breeds it may develop later compared to a smaller dog. Often, this stage is also known as "teenage flakiness" according Ellen Dodge in her article "Critical Periods in Canine Development" published in the Weimaraner Magazine. October (1989).

In the wild, dogs at this age are allowed to go on hunts with the rest of the pack. At this stage, it is important for them to learn to stick with the pack for safety, but they also need to learn about fear since they need fear for survival purposes.The message to the puppy is to run away if something unfamiliar approaches them, explain Wendy and Jack Volhard in the book Dog Training for Dummies.

Reactivity levels rise during this stage causing the dog to act defensively, become protective and more territorial. Owners often report the fear seems to pop out of nowhere. Dogs appear fearful of novel stimuli or stimuli met before but that did not trigger significant reactions. As in the first fear period, it is best to avoid traumatic experiences during this time such as shipping dogs on a plane and any other overwhelming experience. Because at this stage the owner may be dealing with a dog barking and lunging and pulling on the leash, this fear period has a bigger impact, causing the owner to worry about the dog's behavior.

How to Make Things Better

  • Continue socializing as much as possible but without exposing your dog to overwhelming situations
  • Create positive associations through counter-conditioning
  • Build confidence through training and confidence building sports and exercises
  • Avoid traumatic experiences during this delicate phase.

Is There a Third Fear Period?

Clarence Pfaffenberger," author of The New Knowledge Of Dog Behavior " suggests there is a third fear period taking place in early adulthood. During this time, the level of aggression may increase and the dog may appear more protective and territorial. Episodes of teenage flakiness may still occur. Some believe there may even be a fourth period as the dog reaches early adulthood, but I couldn't find reliable literature on that.

General Tips for Dealing With Fear Periods

These tips will come handy to help you deal with your pampered pooch's fear periods. However, they also work for dogs who are fearful in general. While they are effective, keep in mind that your dog's tendency for being fearful may be the work of genetics rather than a temporary problem resulting from a fear stage. To learn more about how nature and nurture molds dog behavior please read: Dog Behavior: Nature versus Nurture Debate Following are some tips to help your puppy or dog get through these frightening fear periods:

Remain as Calm as Possible

You can lie to your boss, but when it comes to dogs, they are masters in reading our emotions and body language. If you are overly concerned or just a bit tense about your dog acting fearfully or defensively, rest assure your dog will perceive it. Don't put tension on the leash, get tense or talk to your in worried manner. Stay relaxed and loose.

Pretend It's No Big Deal

Your dog feeds on your emotions. Just as mother dog would take her pups out from the den and guide the puppies through threatening and non-threatening situations, manifest to your dog that the stimuli he fears is not a big deal. Some find that saying in a casual tone "It's just a _______(fill in the blank), silly boy!" helps the dog understand it's not a big deal.


If your dog acts fearfully towards a certain stimuli you can try to change your dog's emotional response by using treats or anything the dog finds rewarding. The moment your dog sees the threatening stimulus give treats, the moment the threatening stimulus disappears take the treats away. The same can be done with sounds the dog finds startling, make the sound become a cue that a tasty treat is coming. What if your dog won't take treats? Most likely, the stimulus is too scary and the dog is over threshold.

Don't Overwhelm, Desensitize!

Work, under the threshold from a distance your dog or puppy does not react fearfully and is able to take treats. If you overwhelm and flood your puppy, you risk sensitizing your puppy which means you make him more fearful. Don' t force your puppy to interact with the feared stimulus; rather allow him to investigate whatever he fears on his own and remember to praise/reward any initiative your puppy or dog takes!

Socialize, Socialize, Socialize

Fear periods are part of a dog's developmental stages. The more your dog is exposed to stimuli and learns there is nothing to be scared about, the more confident he will be in the future when he will encounter anything intimidating. While the window of opportunity for the puppy socialization phase closes at around 14 to 16 weeks, socialization opportunties should virtually never end.

Don't Punish the Fear

Last but not least, avoid punishing the fear. It is appears that the majority of dog aggressive displays are due to fear; therefore, by punishing the behavior you will be only exacerbating the fear. Ignore the fear and let your dog build confidence by letting him investigate things on his own when he is ready and praising for the effort. Use force-free behavior modification such as desensitization and counterconditioning

While behaviorists have studied fear periods for some time, it is important to keep in mind that they may not occur within that exact time frame for each puppy. If your dog is going through a fear period, keep in mind that it is not the end of the world. With guidance, desensitization and counter conditioning, your puppy or dog should recover nicely with time.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

  • My 14-month old Pitbull puppy is suddenly exhibiting some fear of the vet, for no reason that I can determine. I am now worried about getting her spayed. Should she be given Valium?

    It may help to take her to happy "vet visits" several times before her spay surgery. Just pop in the office and have the staff feed her treats, then go back home. Make the visit the perk of the day. If you are still concerned, inform the vet. He or she may prescribe sedatives to give before vet appointments if they're deemed necessary.

  • My dog loved playing with the neighbor kids when he was 4-8 months old. Now he is so scared; shaking, growling, etc. when they are around. Our neighbor kids are not fearful of him even when he is not nice. He is about 18-months-old now. How can I socialize him around children without putting kids at risk of him barking and snapping (which hopefully will never happen..hasn't yet, but just to be sure)?

    You are right to be concerned. An excellent place to start would be implementing some desensitization and counterconditioning at a safe distance. Perhaps feeding high-value treats when watching kids from behind a window at home or in the car. Then move to the yard safely behind the fence keep him leashed at a distance and keep feeding high-value treats for seeing the kids/hearing them. Afterward, for any closer "socialization" he should always be leashed and at a distance from the kids (under threshold), but because things can get risky here, you really should be working with a professional for safety and correct implementation. If you push him over the threshold, he may regress rather than improve, and things may get more challenging. The more he rehearses fearful behaviors, the more difficult to overcome. I would not expose him to very rowdy or noisy play, as it can stress him out.

© 2012 Adrienne Janet Farricelli


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    • profile image


      5 months ago

      My lab is 7 and suddenly has become nippy. How do I break this habit that recently formed?

    • profile image


      5 months ago

      Please someone help my Great Dane puppy is 13-14 weeks old he is fabulous minds well is protective of me and my two kids but he hates my husband he bit him last night and drew blood my husband says it’s up to me since I’m crazy about him I don’t have to rehome him but I can’t have a dog that bites around my children can anyone help me with this ?

    • profile image

      Fiona Johnston 

      5 months ago

      Why is my yorkie suddenly scared and bearing her teeth to my daughters 2 yr old mini schnauzer who is a gentle boy when he comes to visit. They are walked daily by a dog walker and no problems, its just when he visits her home. Please advise

    • profile image


      11 months ago

      I rescued two puppies 8 months ago. They were both very traumatized and I dont know what theyve been through. One of them is particularly more traumatized than the other. I have worked with her all these months and she allows me to pet her even though she still shies away when I approach her with food or move suddenly. Yesterday she got outside the gate and wouldn't come in and stayed outside the gate the whole night. She stayed out all night refusing to come inside. I eventually caught her at noon after being outside since 5pm yesterday. She is now even more skittish and frightened of me than before. I am at a total loss of what to do.

    • profile image


      12 months ago

      My dog loved playing with the neighbor kids when he was 4-8 months old. Now he is so scared, shakes, growls, etc. when they are around. Our neighbor kids are not fearful of him even when he is not being nice. He is about 18 months now. How can I socialize him around children without putting kids at risk of him barking and snapping (which hopefully will never happen..hasn't yet, but just to be sure)?

    • profile image


      13 months ago

      My husband and i purchased our pup when she was 5 months old. She is terrified of my Husband. She runs to me and is great with me, however when my husband opens the door to come or go outside, she wont come in, and she runs away when he enters the room. This has been her attitude since we brought her home. Help suggestions please.

    • profile image

      Lisa McClelland 

      13 months ago

      I work in rescue. A foster puppy of mine from 2 years ago was just returned to me. The dog is afraid of everyone and everything. The people who adopted her boarded her at 6 months for two weeks and her shyness turned into full blow fear of everything. They no longer wanted to deal with her. It has been 4 months that I have been fostering her now at 2 years old. She is pretty good with me, and after 2 months would come to me on her own and started using the dog door to go out with another dog to go potty. Before that I had to keep a harness and leash on her in a fenced yard to go outside potty. She was so afraid of everything she wanted to just hide in the bushes or try to go under the deck. She did not eat any food for over a week other then a bite here or there and lost 6 pounds. She is now on Prozac and that has helped a lot after three weeks of taking it. She is able to go for a walk with the pack here, but not solo, she can not ride in the car with out trembling severely, and she is unable to meet anyone new. I have been doing counter conditioning with her, but most time she is unable to take a treat. My question is what is your feeling about adopting this dog to a home. I am her foster right now. She is still very skittish at my house with the people in my home. She loves my dogs and will play like a normal dog when it is just me at home. I truly fear adopting her out, that it will traumatize her more, she may flee and never be caught, and the adopters not following my directions or keeping her on her meds. Please give me your insight. Thanks

    • profile image


      17 months ago

      you are right to think

      this sounds good to me as well - despite the fact that Laddie is a year and a half I think this is precisely what he is experiencing. I didn't get him from my raiser until near 5 months so I thin his socialization and improvement are somewhat behind and he has dependably been somewhat modest. I spent his initial summer taking him wherever - puppy fairs, canine parks, strolls, and so forth and he appeared to leave his shell. Be that as it may, this end of the week, he was frightful once more. So we will take gradually until the point when he winds up noticeably balanced once more

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      18 months ago from USA

      Jennifer, it good to have her meet at her own terms, but be careful if she has a history of growling/nipping. If people stretch their hands out to pet her, she may startle and try to nip. The safest option is to have a professional guide you through behavior modification. It's best to nip this in the bud if it's a new behavior before it puts roots.

    • profile image

      Jennifer Van 

      18 months ago from Wisconsin

      Thank You for the information. I have a 9 month old blue nowe pit she is so loveable to our family but gets growly and nips if others try to pet her. I tell them to let her come to them I hope I am doing the right things. Thank you for the information!

    • profile image


      19 months ago

      Well done to all the dog breaders! You have taken the wolf and left us with only fear! All I read is that dogs are afraid of everything.

    • profile image


      20 months ago

      I have a pitbull that I've had since she was 6 weeks old and is now 4 years old and acts afraid of me since day one I have never hit her or had crazy yelling around her. When I call her name she runs to her kennel unless I say let's go to bed or go potty so I am very concerned why is she is still like this after many years

    • profile image

      Laddies Mom 

      20 months ago

      this makes a lot of sense to me too--even though Laddie is 18 months I think this is exactly what he is going through. I didn't get him from my breeder until close to 5 months so I thin his socialization and development are a bit behind and he has always been a bit shy. I spent his first summer taking him everywhere--dog fairs, dog parks, walks, etc. and he seemed to come out of his shell. But this weekend, he was fearful again. So we will take slowly until he becomes adjusted again.

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      22 months ago from USA

      The soccer games can be too overwhelming for her. There's lot of noise, people cheering and this is too overstimulating and sets her on edge. She is likely feeling threatened and is asking for space. You can try to sit in an area where there are less noises and commotion if that's feasible. If people are coming close, you can try feeding her a high-value treat every time a person comes near and ask the person to please not interact with her. If you do this often enough, she may learn to predict that people coming close =treat. But you really need to be her advocate, and not let people come too close or she'll be over threshold and react. If your dog still seems stressed or doesn't take treats, I would skip the soccer games for now and try doing this exercise in a quieter place like a park and feed treats every time somebody walks by. Even best, have a trainer help you out and enlist the help of volunteers that can help your pup form good associations between people walking nearby and treats. Best wishes!

    • profile image


      23 months ago

      This article is very helpful, but I'm still quite unsure of what to do about my puppy. She is 8 and a half months old, and scared of people and kids. I try to reassure her that she's ok and not to baby her over it. We have started taking her to my daughter's soccer games to help socialize her, but when we get there she shakes terribly, and then she growls when anyone gets close to us. I have my husband tell people she's in training and not to come pet her, but when someone, even kids come close, she growls and barks. I'm not sure if I should keep taking her to the games or stop taking her? I just don't know. She also gets scared at home of people visiting, but she doesn't act aggressive at home like at the soccer field, she's just scared at home. Once we tell people to not come near her, let her come up to them, she usually comes over after several minutes, and she's fine after that. I'm really worried this isn't a stage. My puppy is a golden lab that we got from someone who had to get rid of her at 3 months, so we don't know if something happened to her before us. Thank you for the article. It's very informative.

    • profile image


      23 months ago

      Thank you for this helpful information! Our puppy is almost 7 months old and is suddenly afraid of many things she didn't used to pay any attention to. How long does this phase usually last?

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      23 months ago from USA

      You're welcome Elizabeth, thanks for stopping by.

    • profile image


      23 months ago

      I read this, as I'm anticipating I may bring another Baby into the Family. I'm reading up on things I've never known about in 40 odd years of living with Dogs. Very interesting article, thank you.

    • profile image


      2 years ago

      Be very aware of this stage in a dogs life. I was walking my dog through a wooded area near my home and someone came up on a bike. My dog was off lead at the time and we were away from the main road. I just carried on and acted as usual encouraging her to go past the people on the bike. The result was that she about turned and ignored me running back through the woods and across the road ..... she was knocked down and is now recovering from a broken leg. She has never reacted to bikes in this way before and has met many on our previous walks (She is 12 months old) which is why I wasn't too concerned when we encountered these bikes. My only conclusion is that it was the helmets they were wearing. Thankfully she wasn't killed ...... but we are now on the path of recovery and, when she is well, will reintroduce bikes and helmets in the hope that, once again, we can resume our walks through the woods.

    • profile image


      2 years ago

      My puppy is 13 weeks, unfortunately there wasn't a puppy class near me running until a week away, and today when walking he met another dog, and even though the dog didn't com near him or acknowledge him he cried and panicked, low to the ground tail between his legs. I'm really worried that I've missed the chance to get him used to other dogs

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      2 years ago from USA

      Often fear in older dogs is due to reduced senses, like not seeing or hearing well as before, but could also be something happened outside that scared him.

    • profile image


      2 years ago

      What about a 13 year old dog that is suddenly afraid to go outside...front or backyard?...i don't know what to do...we even stand with him!

    • profile image


      2 years ago

      Thank you for the science behind this phenomenon. I was concerned that there was something real that was threating to the puppy as she is now afraid to come in the house. She has been the most enthusiastic pup - happy about everything and everyone. I hope her happiness returns soon!

    • profile image

      Cindy Schmidt 

      3 years ago

      Thank you for this article. I have an 8 mos choc lab puppy dog. I got her at 8 wks. She was socialized quickly and now she is so fearful of everything that she's not familiar with. She loves people, and pets. But everything else she's so skiddish. I'm working to reinforce everything positive. I try to stay calm, if she is really overwhelmed, I remove her or whatever is the problem and make no big deal of it. This is my 3rd choc lab, and this is the first time I've encountered this behavior. She had absolutely no aggression in her. She is so gentle.

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      4 years ago from USA

      Thanks, this helped me when my dog was younger and undergoing a fear period.

    • PNWtravels profile image

      Vicki Green 

      4 years ago from Wandering the Pacific Northwest USA

      Some interesting research and useful suggestions to help make your dog less fearful.

    • Ashley Ryan P profile image

      Ash Ryan 

      4 years ago from Red Dirt Country

      I never knew this was a thing! I have an 8 week old Boston Terrier (along with a 2 year old Boston, also) ...most things she's totally comfortable and then all of a sudden with those same things she seems to become easily frightened. Poor baby! Now it makes so much more sense. :) Great read!

    • alexadry profile imageAUTHOR

      Adrienne Janet Farricelli 

      6 years ago from USA

      Arf, thanks for stopping by. My male went through this as well. Confidence building exercises can be helpful and so is counterconditioning best wishes!

    • A r F profile image


      6 years ago

      This makes so much sense. My puppy is 9 months old right now and is scared of everything - the broom, the umbrella, big trucks. I try not to make a big deal about it, but it's good to know that she will probably grow out of it soon. Thanks for a very informative hub!


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