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San Diego Humane Society

Puppies: Fear Periods and Reactivity

Is your puppy suddenly freaking out and scared about everything? Don’t panic. This is a normal stage called the “adolescent fear imprint period.” With some patience, love and counterconditioning training, you can help your dog feel more confident and safe in a variety of surroundings. 

What Is the Adolescent Fear Imprint Period?

As you puppy gets older, their unquestioned acceptance of everyone as a friend is replaced with caution. They’re asking themselves: “Are you a threat?” or “Are you supposed to be here?”

You may see them shy away from people wearing dark sunglasses or those carrying a large backpack or purse. They may also startle if someone enters their space quickly or unexpectedly. 

Dogs in this stage may show signs of fear at any number of seemingly silly things. They may be afraid to enter your living room, because you’ve added a new decoration. A coat or sweatshirt that you drape over a chair might spook them. They may suddenly notice things that have been there all along — like a fire hydrant on your routine walking route — and react. All of these behaviors are normal and happen due to environmental contrast. They are on high alert when they perceive things that aren't "normal."

Why Does This Fear Period Happen?

When puppies reach adolescence (between the ages of 6 and 18 months), it’s almost like they wake up one day and notice more things at a greater distance away. Suddenly they’re acutely aware of the dog across the street or the kids who ride bikes by your apartment every single day. Their reaction starts with a few suspicious “woofs,” followed by "bowrrrooooooo-roooo-rooo" going up in pitch. The intensity of your puppy’s reaction depends on how socialized they were early on. 

By letting this behavior happen, you’re unintentionally building their confidence in their ability to scare away the mailman or neighborhood kids who are out for a bike ride. This is not ideal. No one wants their dog to become an expert in scaring others, nor do you want them to continue practicing this unwanted behavior because they are afraid. If they find out that lunging and barking will make the scary thing go away, they will assume that this if effective and continue doing it.

How to Overcome the Fear Period

Socialization and counterconditioning — training your pet to have a different response to a stimulus — are the most effective techniques for overcoming these behaviors. With all dogs, patience and persistence is key! 

Watch for Stress Signals

First, learn to watch for signals that your dog is stressed, so that you can intervene before they feel the need to bark. Your puppy may do this:

  • Look away from the scary thing.
  • Lick lips.
  • Raise paw.
  • Whale eye (the whites of the eye showing).
  • Tightly shut mouth with or without teeth showing.

If you see any of these behaviors, move your dog away from the stimulus they perceive as scary. If pushed beyond their safety threshold, they may do the following:

  • Bark with hackles (the ridge of hair down the dog's shoulders and spine) raised.
  • Cower behind you.

This behavior is their defense mechanism to make the scary thing go away. So what’s the solution to this problem? Socialization!

How to Socialize Your Puppy

Help your pup to associate the scary thing with a positive reward (e.g., a high-value treat). This conditions them to think that seeing the mailman/neighbor’s dog/kid on a bike = cream cheese. By doing this over and over and over again, you are counterconditioning your dog. Eventually, with time and repetition, they will look to you for a treat when they see the scary thing, rather than barking, lunging or cowering.

The good news is dogs may grow out of their adolescent fear period — with support and guidance from their pet parents. It is important to continue to expose puppies to new things at a very safe distance, where they are not reacting and still accepting treats. Avoid exposing them to a lot of scary things at once or at a very close proximity.

Potential Medical Issues

If your normally friendly dog suffers from a "sudden onset" of out-of-character behavior, there could be a medical reason. Thyroid imbalance, chronic pain or even allergies can cause dogs to behave differently. Consult your veterinarian.

Behavior Helpline: Contact our Behavior Team

For behavior questions, please contact our Behavior Helpline either by calling 619-299-7012, ext. 2244, emailing or filling out our Ask a Trainer form. San Diego Humane Society Adopters can fill out the Post Adoption Consultation form to schedule their troubleshooting session. We aim to respond within 7 days, but responses may take up to 2 weeks. Thank you for your patience!

Note: Due to the potential for serious injury, canine and feline aggression are best handled by a professional who specializes in aggressive behaviors. Because phone or email counseling is inadequate for addressing serious behavior concerns, we ask that you contact a qualified professional for help. Please refer to the list of behavior resources here.

Questions About Public Classes

San Diego Humane Society offers training classes and resources to address a variety of needs for companion animals.

Our training philosophy is based on the behavioral science concepts of positive reinforcement. Training your pet using these concepts will not only help them learn new behaviors more quickly, it will also strengthen the bond you share.

Our website includes a current schedule of training classes or call 619-279-5961. 

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