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Sensitive Periods for Puppies – When & What To Do

↯ Key takeaway points

  • Owning a puppy can have many benefits, including reducing stress and loneliness, increasing activity levels, and providing a sense of security.
  • Puppies go through multiple sensitive periods during their development, including the neonatal period, transitional period, socialization period, fear periods, and adolescence period.
  • During each sensitive period, puppies need specific actions and experiences to support their mental and physical development.
  • It's important to be aware of signs of illness in puppies, including lethargy, poor appetite, loose bowel movements, persistent vomiting, continuous whimpering, and non-stop itching or licking.
  • Socialization and fear periods are crucial for puppies, and it's important to provide safe and positive experiences during these periods to prevent anxiety and fearfulness later in life.
Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Zoo and wildlife doctor in veterinary medicine passionate about animal welfare and preventive medicine.
Published on
Wednesday 14 April 2021
Last updated on
Thursday 20 July 2023
sensitive periods for puppies
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Owning a puppy for the first time is a truly rewarding but challenging experience. And, as a doting pet parent, you want to do everything you can to support your puppy as they grow. Part of raising your puppy involves learning about sensitive periods for puppies. But what is a sensitive period? Your puppy will undergo multiple sensitive periods, each one crucial in your little one’s mental development.

Here, we discuss each puppy sensitive period in detail so that you can help your puppy. Each sensitive period calls for a different line of action from you and you must be able to identify each one. Ready to learn about socialization and fear periods? Let’s get started.

Benefits of Having A Puppy

Owning a puppy for the first time can be both rewarding and challenging. As a loving pet parent, you want to do everything you can to support your puppy’s growth. Part of raising a puppy involves understanding their sensitive periods, which play a crucial role in their mental development.

Sensitive periods are specific phases in your puppy’s life where they are more receptive to learning and experiencing new things. Each sensitive period requires different actions from you as a pet parent, and it’s important to recognize and address them accordingly. Let’s delve into two important sensitive periods: socialization and fear periods.

Having a puppy has many benefits beyond companionship. It has been shown that caring for a puppy can help alleviate mild to moderate cases of clinical depression. Interacting with animals, including puppies, can lower our stress levels, combat loneliness, and encourage social interaction. By owning a puppy, many people find themselves becoming more active, which in turn reduces stress and improves overall health. Engaging in activities such as visiting new places, attending puppy training classes, and connecting with other puppy owners can significantly enhance one’s social life. Lastly, owning a puppy provides a sense of security, knowing that your furry friend will grow up to be a loyal companion and guardian.

Sensitive Periods for Puppy Development

A sensitive period is a phase when your puppy is most receptive to learning and benefiting from exposure to various things. For instance, the socialization period is the best time to introduce your puppy to other people and dogs. If your puppy doesn’t have new encounters, meet different people, encounter objects, or have new experiences, they may develop problems with anxiety, aggression, and fear as adults.

Neonatal Period of Development

Your puppy’s neonatal period begins at birth and ends at around two weeks. During this stage, your pup is entirely dependent on their mother. It is important that your puppy feels safe and warm for this crucial part of their life, as they primarily experience physical sensations like hunger and warmth rather than emotional states. This is because the brain is not yet fully developed.

neonatal period of development
During the neonatal stage, your pup is entirely dependent on their mother.

Transitional Period of Development

Your pup begins its transitional development at two weeks old. Then, the period ends at around four weeks old. A two-week-old puppy’s eyes and ears begin to open, granting them their critical senses of sight and hearing. Also, their baby teeth begin to emerge. Your two-week-old puppy even begins to walk, bark, and wag its tail. All of these changes are critical for your pup’s emotional and physical development. Because a puppy in this period of development can see and interact with their littermates, they learn the rules of play, bite inhibition, and body language. By three weeks old, many puppies also begin weaning. This process is critical in getting your pup to eat independently, rather than relying on their mother’s milk. Overall, your puppy begins to socialize and gain more independence during the transitional period.

Socialization Period of Development

Right after the transitional period comes to a close, your puppy’s critical socialization period begins. This period occurs between 3 weeks and 14 weeks, though researchers may disagree on the exact timing of it. The social period gets its name for a very good reason – during this time, your puppy must be exposed to a variety of humans and animals. Regular, gentle handling is necessary at least twice a day. If a puppy does not get this vital socialization and handling experience, they will struggle to socialize and cope with stress later on. You may even find that your puppy develops specific phobias and dislikes of groups of people or other dogs if socialization is not done or is unsafe for your puppy.

Fear Periods

Your puppy’s first fear period overlaps with their socialization period, starting at around 8 weeks and finishing at 11 weeks. Because your puppy is learning so quickly and profoundly, a traumatic experience at this time may have life-long consequences. You must avoid frightening your puppy during this time. This means that children and animals must not be allowed to hurt or frighten your pup. The second fear period occurs between 6 months and 14 months of age, and similar principles apply.

Adolescence Period of Development

The adolescent period in puppies begins at 6 months and extends to 18 months or more. Some dogs will reach adolescence sooner, while others may not enter this period until they are 10 months old. Dogs who enter adolescence sooner tend to exhibit more attachment and attention-seeking behavior than those who start adolescence later on, research suggests. But, generally speaking, adolescent puppies have more energy, and may “forget” their training. You must practice regular obedience training with your pup and give them extra exercise during this time. Although your puppy’s behavioral traits will be well-established by now, any major traumas during this time can have long-term effects. Be sure to continually provide positive socialization experiences for your puppy.

adolescence period of development
Some dogs will reach adolescence sooner.

What to do During Sensitive Periods for Puppies

Knowing how to support your puppy during important developmental periods is crucial for responsible ownership. Failing to meet their needs during these stages can result in a puppy that struggles with social situations and stress. So, what do these sensitive periods for puppies involve?

Natal Period

The best thing you can do for your newborn puppy is to allow them to stay with their mother until they are at least 8 weeks of age. Your puppy must be kept safe and secure during this period because they are completely defenseless. Make sure that your puppy is fed and toileted by their mother, and regularly handle them to get some early socialization done.

Transitional Period

The transitional period is a time of great change. Your role is to provide your puppy with the toys and socialization opportunities they need to get the most out of this period. Your puppy should have access to their littermates so that they can learn to play and interact with members of their own species. As a puppy in the transitional period also gains their first baby teeth, you must be sure to provide your puppy with a wide range of toys with different textures to encourage positive exploration and play.

Socialization Period

Perhaps the most important period, the socialization period in puppies is what governs your puppy’s social abilities later on. Your role is to expose your puppy to both familiar and unfamiliar people so that they can learn how to interact with them. Without this socialization, puppies may become fearful and avoidant of others as adults. They are also less able to cope with stress than their well-socialized counterparts. However, socialization that is overwhelming or frightening for your puppy can also have negative effects on them. Make sure that your puppy interacts with people and animals who will not frighten your puppy through aggressive behavior.

Fear Period

Overlapping with the socialization period, the two fear periods in puppies are also crucial times in your little one’s development. The first fear period overlaps with the socialization period, starting at 8 weeks and finishing at 11 weeks. So, your role is to ensure that your pup’s socialization is done safely. Any traumatizing or frightening incident during this period can have life-long effects, such as specific phobias or an inability to cope outside of the house. When socializing your pup with children, make sure that your puppy is not grabbed, chased, or harmed to avoid future problems with children.

The second fear period happens between 6 months and 14 months of age. Generally, this critical period begins sooner for smaller breeds and later for larger breeds. This time around, the fear period focuses more on situations than specific dogs and people. If your puppy is afraid of a new situation, do not force them into it, and do not punish them. Your puppy’s fear must be handled with patience. Also, be sure to praise the behavior that you want to see. Routine training exercises during this time can help to build your puppy’s confidence, so be sure to keep up the hard work!

Adolescent Period

Your puppy enters adolescence at around 6 months old. This period usually ends at 18 months of age. Unfortunately, this “teenage phase” is what most often lands puppies in shelters in the USA, as many owners find themselves unprepared for the challenges that this phase brings. As a responsible owner, your role is to manage your puppy’s teenage phase fairly. During this phase, your pup may “forget” their training, challenge your boundaries, and chew on things that you previously taught them not to chew. You must not punish or otherwise mistreat your puppy during this time, no matter how much they misbehave. Continue with your training, and start with the basics again if you must. When your puppy behaves in a way that you do not like, make sure to correct and redirect the behavior to something that you do want to see.

Signs of Illness in Puppies

Knowing the signs of illness in your little ball of fur is essential in supporting them through their sensitive periods. This is because anxiety and reluctance to do things as a result of pain can be mistaken for the behavioral changes that come with sensitive periods for puppies.


Your puppy has a lot of growing to do, so naturally, they sleep more than their adult counterparts. However, your puppy should not be lethargic. If your puppy is showing a lack of enthusiasm, sleeps too much, or generally seems despondent, consider talking with your vet. Lethargy is a symptom of many different illnesses in puppies. These range from milder problems like hypoglycemia to life-threatening parvovirus infections. Other health problems include distemper, kennel cough, leptospirosis, heart problems, liver disease, and diabetes.

Poor Appetite

Your puppy needs plenty of healthy, nutritious food in order to grow. So, a lack of appetite in puppies indicates an underlying problem. There are many things that can cause your puppy to lose their appetite, including infections, pain, and the way that you feed them. Stress is also a major cause of appetite loss in puppies. If your puppy regularly refuses their food, consider talking to your vet for advice.

Loose Bowel Movements

Your pup is going through a lot of stressful changes, from weaning to sensitive periods, and diarrhea comes with the territory. However, diarrhea may also point to an underlying problem. If your puppy also loses their appetite, vomits, and loses weight, you must seek emergency veterinary help as soon as possible. Also, be sure to check your puppy’s stool for blood or parasites. Blood in the stool is never a good sign for puppies and is a problem that must be taken seriously. Parasites like worms may also be seen in the stool, so make sure to check for worm segments as you clean up the mess.

Persistent Vomiting

Occasional bouts of vomiting are usually no cause for concern. Vomiting can be caused by anxiety, stress, or eating a meal too quickly. However, persistent vomiting or vomiting with blood is not normal. If your puppy vomits more than usual, make sure to check in with your vet as soon as possible. This is because vomiting is a sign of several illnesses, some life-threatening for puppies, and can cause dehydration itself.

Continuous Whimpering

Puppies cry for a number of reasons. Whether your newborn puppy is too cold, or your adolescent puppy needs reassurance, crying is a normal part of puppyhood. However, continuous whimpering is a sign that something is wrong with your pup. Your puppy might continuously whimper due to anxiety, stress, or an illness that is causing them pain. Be sure to ask your vet for advice if your pup cries more than usual, just in case if something is causing them distress.

continuous whimpering
Crying is a normal part of puppyhood.

Non-Stop Itching or Licking

It is not normal for a puppy to itch or lick themselves constantly. It is especially abnormal when hair loss accompanies this symptom. If your puppy licks or grooms too much, it could be a sign that your puppy is having an allergic reaction to something. Itching and licking can also indicate that your puppy is struggling with a flea infestation or other parasites that have hitched a ride on their body. Lastly, this behavior may also indicate stress. Some dogs over-groom themselves as a way of coping with something that is stressing them out. In any case, ask your vet for advice so that your pup gets the relief they need sooner than later.

Sensitive Periods for Puppies – FAQs

Have any more questions or concerns about sensitive periods for puppies? Feel free to browse our Frequently Asked Questions section for more details. If in doubt, always ask your vet for advice!

What are the common illnesses in puppies?

Unfortunately, your furry friend is most vulnerable to illnesses when they are young. Diseases like parvovirus, distemper, kennel cough, leptospirosis, and adenovirus are significant threats to puppies. As such, you must keep up to date with your puppy’s vaccinations to protect them from these illnesses. Puppies are also prone to diarrhea and vomiting as they learn to cope with stress, especially through the weaning process. If your puppy has diarrhea during weaning, be sure to slow down the process and take a step back if you must.

What does a puppy’s ‘fear period’ refer to?

A fear period is a time in your puppy’s life when frightening things can have a significant impact on their mental development. In short, this means that, if something deeply frightens your puppy during this time, they can develop a specific phobia of that object or situation in adulthood. For example, if your puppy was attacked by a dog during the fear period, they could develop a disabling fear of that dog breed or coat color. Similarly, being frightened or harmed by a child can cause a dog to grow up with a fear of children.

What to do during a puppy’s fear period?

During the fear period, your puppy is more sensitive to things that seem normal to us. This includes meeting new people, new dogs, or engaging in new situations. When your puppy shows avoidance or fear of something, your reaction is crucial in your puppy’s response. You must stay calm and act as if the situation is normal to you. By doing this, your puppy will learn that there is nothing to fear about the experience. You must not punish your puppy or force your puppy into the situation if they are afraid. Punishments will only enforce that the stimulus is in fact something to be afraid of, and can even teach your pup that you too are someone to be feared.

When does the socialization period occur?

A puppy’s socialization period occurs between 3 and 14 weeks. However, research debates the exact amount of time that this period goes on for. In any case, it is crucial that your puppy gains valuable socialization experience before they are 12 weeks of age. Without this experience, puppies grow up to become anxious and unconfident in social situations. They may be unsure or even afraid of interacting with different types of people, too.

How to safely let a puppy socialize with other dogs?

While socializing your puppy is important, it is more important to keep your puppy safe whilst they learn. You must keep a collar on your puppy and keep them leashed in public. If your puppy has not been vaccinated, you must avoid unvaccinated dogs, or dogs who have recently been unwell. It is also important to avoid areas where parasites might lurk, such as tall grass, which can harbor ticks. When possible, be sure to fully vaccinate your pup for their protection.

You want the best for your new furry friend, so learning about these critical times in your pup’s life is essential. You play a huge role in your puppy’s socialization and fear periods, and understanding the impact of this is key in helping your pup to grow up to be a well-balanced and confident adult.

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