Puppy Stages: 16-Week-Old Puppy Behavior and Development

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

What to Expect?

If you are wondering what happens when a puppy is 16-weeks-old, most likely you are considering adopting a puppy of this age or are wondering if your 16-week-old puppy's behaviors and development are normal for this age. What happens at this age? What behaviors should you expect?

At 16 weeks, the puppy's grace period for critical socialization has closed. Indeed, this brief window of opportunity according to veterinarian and Animal Behavior PhD, Ian Dunbar, takes place between four and twelve weeks of age. What happens if you missed the boat or your vet recommended you to wait until your dog's series of vaccinations were completed? Karen Overall, Veterinarian, Diplomate of the American College of Veterinary Behavior claims in a handout prepared by the Pet Professional Guild:

"People need to realize that vets don’t know that much about problematic behavior, or maybe even normal behavior. The single biggest reason people relinquish animals to a shelter is a behavioral problem.”

At this point, if you haven't socialized your puppy, you are left with the option of what is known in dog training lingo as "remedial socialization." This doesn't mean you'll have to make up for the missed time and flood your dog with stimuli! This will likely overwhelm your puppy and cause more damage than good. Instead, gradually and systematically expose your dog to people and other dogs. Make sure you have established a certain level of trust and bond with your puppy. Use high value treats to create positive associations. If your dog appears fearful, respect that and don't force him to interact—as of yet. Then figure out a way to systematically desensitize and counter-condition him to that fearful stimuli

There are several things going on from a developmental and behavioral standpoint in puppies at this age, in the next paragraph we will go over them.


At 16-weeks, puppies still retain several puppy characteristics enough for causing people to "ohhh" and "awwww" at the sight of them. Yet, they are undergoing several physical changes that are gradually morphing them into young adults. They are undergoing rapid growth and are becoming taller and longer, but their minds are still like puppies. At this age, they are also almost reaching half of their adult weight. Following are some developmental stages observed in 16-week-old puppies.

Changing Hairdo

In the article on 12-week-old puppies, we saw how the 12-week puppy still retained some of that soft, puppy hair. Now, one month later, at 16 weeks, you may start seeing a bit of adult hair. In the 16-week old Lab mix in the picture, you can see how she started showing the first zig-zag hair in the back as seen in many adult Labs. A month earlier this was not visible.

Puppy Teething

At 12 weeks, the puppy was starting to lose some of its baby teeth. Now, a month later after losing the incisors, you may start seeing the first adult, permanent incisors coming in by the age of 5 months. The canine teeth may also fall out at around 16 weeks. This is a time where the puppy has sore gums and likes to chew. It's very important to find a safe, age-appropriate puppy chew toys at this point. Chew toys and bones crafted for adult dogs may fracture a puppy's delicate teeth.

Bladder Control

Those bowels and bladders are now starting to gain more control. Where at 12 weeks, puppies were able to hold it for two to four hours, now they can hold it even up to about five hours. Most puppies at this age can hold it all night. Crate training should continue if this is the chosen method used for potty training.


There are many behavior changes taking place in these puppies. As usual, they will have boundless energy and will engage in lots of play. Puppy owners may feel overwhelmed at times by boisterous activity. This is a good time to keep the mind stimulated through training and appropriate play.

Pups Become Warier

As mentioned, this is the time when the window for socialization closes. This socialization phase during which dogs have less fear of the unknown has a distinct purpose in nature. Respected dog trainer and author Jean Donaldson, explains in her book "The Culture Clash," that this brief "window of time” is there so young pups have the chance to become better acclimated (the correct term is habituate) to sights, sounds and experiences within their surroundings. It is meant to be there so animals aren't spooked by harmless stimuli such as the trees, rocks, and birds chirping. Then once, this window is closed, animals start becoming more wary of novel stimuli. This suspicion has an adaptive function. It helps increase the chances for the pups' survival because it prevents them from getting in contact with stimuli that may harm.

Curious Rovers

The saying "curiosity killed the cat" may apply to puppies as well. During this time, puppies are curious about learning about their environment which makes them more likely to get into things and into trouble. Keep an eagle eye on what your puppy tries to eat in the yard and on walks, at home, make sure your home is puppy proofed. At the same time, puppies may have moments where they are fearful of things. They may move tentatively towards new objects and may be intimidated by noises. It's important that they are allowed to investigate scary stimuli on their own and that they're praised for taking initiative.

Activity Levels

At 16-weeks, puppies are still a bit clumsy, but they are getting better at coordinating their movements. Most have boundless energy and are eager to romp, play and jump for a good part of the day. Fortunately, at this age, they also tend to sleep a lot!

Further Reading

  • Understanding Puppy Teeth Stages
    Confused by the puppy teeth stages? No need to be! This guide will reveal the whole process clearly and will provide some interesting, little-known facts about your pup's teeth.
  • The Pros and Cons of Using a Puppy Apartment for Pot...
    An honest review of the famous puppy apartment for potty training by a dog trainer. Read the pros and cons and what my clients are complaining about.
  • Why Does my Puppy Pee After Going Outside?
    Is your puppy peeing right after you took him outside? There are several things going on in this case, this article offers some troubleshooting.

Questions & Answers

Question: When are puppies considered fully grown?

Answer: In general, puppies reach the adolescent stage at around 6 months. At this time, puppies should have all their adult teeth in. After the adolescent stage is over they are considered adults once they are fully grown. Generally, puppies are considered adults by the time they are 24 months, but of course, there are quite some breed variances. Some smaller dogs and medium can be considered adults between 12 and 15 months, while larger dogs may be considered adults by 24 months or even considerably more in giant dog breeds.

© 2013 Adrienne Farricelli

Lyla on July 29, 2020:

i think dogs liveing outside is a bad idea .

Mindy on September 23, 2018:

Renee, "Vets know nothing about behavior in dogs" is a statement from Karen Overall who is a veterinary behaviorist. A very reputable reference, there as veterinary behaviorists are veterinarians who specialize in behavior. Moral of the story, dogs can and do get potentially fatal disease, but socialization is still very important and it can be done safely. Please get more educated on how to do this.

Renee on June 04, 2018:

“Vets know nothing about behavior in dogs.” Single most hysterical line in this article. Please DO NOT introduce your puppy to unknown dogs before completing vaccines. 16 week old puppies can socialize just fine it’s not like if you socialize a 16 week old puppy it’s forever dog aggressive and won’t know how to interact. Parvovirus and kennel cough are potential fatal diseases in puppies... get your priorities in check

Dee on June 03, 2017:

What kind of puppy is featued in the first photo? I just adopted a puppy that is strikenly similar!

Adrienne Farricelli (author) on May 27, 2013:

Yes! often dog owners can't wait for the puppy stage to be over and then bam!, they are hit hard with the teenager stage, which is also sadly the age dogs are more often surrendered to the shelter:(

Heidi Thorne from Chicago Area on May 27, 2013:

Glad my dogs are waaaayyy beyond this puppy-proofing stage. But still, gotta watch 'em. They never really grow up. :) Love the bit about puppy 'do. Stylin'!

After this stage, they get into what I call the teenage-jerk stage at 6 months. So enjoy the 16-weeker!

Adrienne Farricelli (author) on May 26, 2013:

Thank you for stopping by Yuliss. Every puppy and dog assigned to me always teaches me something new. They're like open books.

Yuliss on May 25, 2013:

This was a really informative post on puppy behaviour. Thanks for sharing your knowledge:)

When will my puppy be a grown up?

There are actually three aspects to puppy development that all need to come together in order for him to be truly an adult dog.

  • Physical maturity
  • Sexual maturity
  • Mental maturity

Your puppy needs to reach all three aspects of maturity before he is a “grown up”.

To confuse matters, these processes don’t happen at the same rate. And the point at which all three are complete varies from one dog breed to another. Let’s take physical maturity first and talk about puppy growth.

Puppy stages: A week-by-week guide to caring for a newborn puppy

There are few things more magical than watching a puppy grow.

If you’re really in on all the action from day one, you’ll watch in awe as they open their eyes, carefully (and sometimes not so carefully) explore the environment around them with their nose and gradually grow into those oversized paws.

To help you know what to expect during the most adorable weeks of a puppy’s life, we asked Dr. Carlo Siracusa, DVM, Ph.D., MS, associate professor of Clinical Behavior Medicine at the University of Pennsylvania School of Veterinary Medicine, to share key happenings and care information through the early stages, from day one to 48 weeks.

Puppy Development Stages

Every puppy is a unique individual - a furry little bundle of needs/wants/instincts and genes - and as he grows and you learn more about his personality you'll find it easier to meet his needs.

Llarge and giant breed puppies grow and mature much more slowly than small or toy breeds, which means that the ages at which puppies of different breeds/sizes go through each stage of development can vary a bit.

The first 8 weeks is pretty standard for all pups, but after that - not so much.

There are three types of changes which puppies go through as they mature:

  • Physical developments
  • Emotional developments
  • Growth and weight gain

Many new puppy owners want to know how big their new puppy will be as an adult.

With purebred pups you can get a reasonable answer to this by looking at the parent dogs. For mixed breeds it is much more complicated.

If you want to know what little Fido might weigh as an adult, check out these pages.

Puppy Development During Pregnancy

If you want to learn all about canine pregnancy, and how puppies develop during the 9 weeks they spend in the womb, check out this page. Dog Pregnancy

First Stage: 0 - 3 weeks

This stage of puppy development is the very beginning of your puppy's life and he's a tiny, vulnerable creature!

Take a look at some puppies being born and you'll see exactly what I mean.

Puppies are born with their eyes and ears firmly closed and without any teeth.

Although you won't see much external activity in a puppy during this period (all they want to do is eat and sleep), there's a LOT going on inside.

In fact this is a very critical stage of puppy development and all that sleeping is actually playing an important role as puppies do most of their growing during that time.

Towards the end of this period a puppy will begin to open his eyes (at around 2 weeks old) and his ears (at around 3 weeks old), then his little teeth will start to peek through his gums.

His eyesight and hearing improve daily, and by the time he's 3 weeks your pup will be toddling around, trying out his voice and beginning to play with his siblings.

Obviously right now your puppy is with his momma and siblings, so the breeder has full responsibility for him.

If you have puppies who have been abandoned or rejected by their momma, or are orphans, they will need you to take care of them.

My Caring For New Born Puppies page has all the tips, advice and information you need to do this properly.

It's a good time for him/her to begin to introduce new things for the puppies to experience and help to stimulate their senses. such as different textures for them to feel (ie. wear different clothing for them to be held against, different surfaces to toddle about on, brush their fur gently and so on).

Different sounds can be introduced such as the radio, tv, washing machine etc.

To help you see how little ones behave during this period of puppy development, here are some adorable 3 week old Cavalier King Charles Spaniel puppies. awwww.

Second Stage: 4 - 11 Weeks

During the second stage of puppy development little Fido will grow very quickly and will mature at the same pace.

He will start to regulate his own temperature during this period, and also start to feel the urge to pee/poop all by himself so he won't need his momma, or you, to stimulate him to eliminate any more.

Your puppy is a now a 'toddler' and he'll be very busy learning how to interact with other dogs (both puppies and older dogs) and with other animals and, of course, humans.

Your puppy's teeth start to emerge during this stage and this means that he doesn't have to rely on drinking milk as his sole source of nutrition.. but he can't switch straight from nursing to eating dry kibble at this point.

His momma will start to wean him by refusing to let him nurse for long periods. In the wild a wolf or wild dog will regurgitate food for her puppies, the ultimate 'baby food'.

You don't see this often in domesticated dogs, but some females do it and it's not to be confused with vomiting!

There's a lot to be learned from their momma during this stage of puppy development. She'll teach him basic 'canine manners' and he will follow her lead in terms of how he reacts to the people and situations he encounters.

A calm, well-behaved momma dog will usually raise calm, well-behaved puppies but a fearful or aggressive momma may transmit those behaviors to her offspring.

A puppy will also learn from his litter mates, and one of the most important lessons is 'bite inhibition' - this is basically how hard he can bite without getting in deep trouble!

This lesson is very important and just one of the many reasons why puppies should remain with their canine families for at least 8 weeks.

During this developmental stage, breeders need to continue increasing the pup's exposure to different textures, sounds, smells etc.

Individual puppies can be given short periods away from their momma and siblings to help them get used to being separated. This is a small step towards helping a puppy feel less frantic when he has to leave his doggie family to go to a new home.

Also because this is the time when a momma dog will start to wean her pups naturally, breeders need to start supplementing the pups diet with a premium puppy kibble soaked in warm water. and offering the puppies water to lap.

Just because the momma isn't feeding her puppies that doesn't mean they are ready to go to new homes. if anyone tells you this they do NOT have those puppies best interests at heart!

And to finish off, during this period of puppy development they should also get their first set of puppy shots and be treated for puppy worms by a veterinarian before the end of this period of puppy development.

Here are the same puppies as shown in the video above, at 7 weeks old. See how much bolder and more playful they are.

Third Stage: 7 - 12 Weeks

That little puppy has grown up pretty quickly and by 8 weeks old he's ready to leave his canine family and go to his new home.

Tiny breeds may mature more slowly and it's better to keep these pups with their momma for up to 10 - 12 weeks.

He may be a little guy, but a puppy of this age is curious, outgoing and intelligent. He's ready to find out all about the world around him and is eager to please his people.

Right now your puppy is the proverbial 'blank slate' and it's easiest time to teach and train your puppy.

He's small enough to control, eager to learn and respects you as his 'leader'. What he learns now will stay with him for life - good or bad - so make it good!

Socialization is also very important during this stage of puppy development. the more new sights, sounds, smells etc. that he can experience the better.

Puppies who have lots of socialization experiences and stimulus during this period will be much better equipped to handle change as they grow.

Countless studies have shown that the best time for a pup to leave his momma and go to his new home is right around 8 weeks of age, so during this stage a puppy often moves to his 'forever home' and family.

Many new owners aren't sure what to expect at first and there is often an adjustment period, you can learn more about the first few days/week with a new puppy on my Bringing Home A New Puppy page.

There is also the first 'fear period' to deal with. This usually comes on during the third stage of puppy development and at around 8 weeks of age. Little Fido may suddenly seem to be scared of his own shadow, wanting to stick close to you at all times.

He's about to take off on a huge learning curve, so it's the perfect time to start introducing your little guy to some basic manners and puppy training. Start basic obedience at home, and then move onto a formal obedience class once he's fully vaccinated.

What you feed your puppy will have a long-term impact on his health and longevity. Feeding one of the best puppy food choices available is a big step towards keeping him happy and healthy, and growing at the proper rate.

It's also vital to balance his need for socialization against health risks. Your puppy is very vulnerable to disease at this point in his life, so NEVER allow an unvaccinated puppy to interact with other pups or dogs who are not FULLY immunized.. also don't give him access to any public areas such as parks, stores, sidewalks etc.

Any fearful reactions are pretty normal at this age, and are usually nothing to worry about. You don't want to 'coddle' a pup who is behaving this way. Just maintain a positive attitude and use a happy, upbeat tone of voice so that he realizes there is nothing to be scared of.

Also, never push your pup to do something that he's clearly terrified of - that will cause more problems than it will solve.

How Big Will My Puppy Get?

The majority of puppies go to their new homes during this stage, and one of the questions I hear most often is 'How big is my puppy going to be when he's fully grown?' Check out these pages for more info.

Fourth Stage: 12 - 17 Weeks

This period of puppy development is kind of like the 'tween' or 'pre-teen' stage that our human kids go through.

Your pup isn't a baby any longer, but he's not really an adolescent either, he's in that no-man's land and you're not the only one who's confused about what he can, or should, be doing!

His confidence is growing by leaps and bounds, but he can unexpectedly slip back into that 'anxious little puppy' mode at any time.

One minute he's all bold and brave and barking at the neighbor's cat, next minute he's trying his best to be invisible - or failing that, hide behind your legs.

For small breed puppies that super-growth spurt he's been experiencing will start to slow down, and his appetite will slow down right along with it.

Larger breeds are still much less mature though and will likely continue to eat you out of house and home for a while longer.

All in all this is a time of transition for your little guy, and his behavior will probably be inconsistent, confusing and maybe even frustrating.

If he's a bit of a challenge rest assured this is normal, and he will grow out of it (but he's got a fair way to go yet!)

Puppies need firm guidelines and lots of love during this stage of development, and the ones to come!

He'll be starting to venture further afield and his growing confidence will sometimes push him out of his comfort zone (now and then WAY out of it) and he's likely to be a bit confused by his feelings and reactions.

He needs you to be calm and patient so that he doesn't get over-anxious or into trouble.

Socialization is a very important part of this stage, and now that he's fully vaccinated your pup can be going out and about with you as much as possible. It's also the ideal time to get him started on formal obedience classes, if you haven't already done so.

Everything he learns and experiences while young will stay with him, and although the old saying 'You can't teach an old dog new tricks' isn't really true, it IS true that it's much easier to teach things to a puppy or younger adult dog :)

Fifth Stage: 18 - 40 Weeks

Congratulations you're raising a teenager!

The fifth stage of puppy development is pretty close to the human 'teenage' years and you'll see a lot more of the 'bratty' attitudes you've probably already been dealing with.

This teen puppy stage can be pretty demanding and more than a little challenging.

Your pup will want to break the rules, test the limits (and your patience) and generally act as though he's forgotten every lesson you ever taught him.

PLUS, he'll be in the middle of teething as well. Yikes!

But don't worry, this is perfectly normal and you don't have a juvenile delinquent on your hands.. yet anyway. If you've followed the advice above during the earlier stages of puppy growth you can relax :)

Rest assured that as long as you continue to set (and enforce with love) the 'house rules' and keep your routine and reactions consistent, your pup will come through this rocky period and emerge as an older, and hopefully wiser, version of that little 8 week old furball.

But, if you haven't done the groundwork yet - then you've got some work ahead of you and you'd better start right now!

Continue to be patient and consistent with him. Some strong-willed pups may try to 'show you who's boss', but it's important to make sure that you stay in charge.

In terms of physical puppy development, your pup will likely look like a teenager as well. long limbs, slender, maybe a bit awkward and ungainly. All normal and you may find his appetite will fluctuate as he goes through growth spurts.

During this period your pup should lose his last baby teeth (the front 'fangs' or upper canines) and will have a full set of adult teeth.

At this stage of puppy development, your pup's greatest needs are for discipline, exercise, sturdy chew toys. and patience!

Puppies grow up much faster than human children, but don't expect miracles or overnight transformations. It's the small, day-in-day-out interactions, the consistent but loving corrections, the patience and persistence that win the day.

Your pup WILL learn, but he's a creature of habit and his learning style is much more of a gradual build-up of understanding than a sudden 'aha moment'. If you follow the guidelines here, it will work out fine in the end, just stick with it.

It's a good idea to get your puppy neutered (or if you have a female, have her spayed) during this period, definitely before 6 months of age.

For an in-depth look at teenage puppy behavior. and how to handle it properly. check out this page Adolescent Puppy Behavior

It covers everything you need to know to get you both through this, often challenging, stage.

Sixth Stage: 40 - 52 Weeks

So what do you have to look forward to here.

More teenage behavior, plus the upheaval of hormones signalling sexual behavior and maturity and another fear period. What fun!

Small breed puppies may reach maturity by the end of this period of canine development, but for the large or giant breed puppies there is still a long way to go!

Some of the extra-large dogs don't become adult until they are somewhere between 2 and 3 years old.

There will be a more noticeable difference between the development of small and large breed pups at this stage of development.

Small or tiny breeds should be starting to settle down in terms of behavior, and they will have reached their full height and weight.

Large or giant breeds will still be in the adolescent stage and there will be the same sort of behavior that you've been seeing for the last few months.

These big puppies will still have lots of growing to do. To get an idea of how big your puppy may be by the time he's fully grown (whether he's a small or large breed), check out my Puppy Weight Estimates page.

At this stage of development, your pup's greatest needs are for discipline, exercise, sturdy chew toys. and patience!

Puppies grow up much faster than human children, but don't expect miracles or overnight transformations. It's the small, day-in-day-out interactions, the consistent but loving corrections, the patience and persistence that win the day.

Your pup WILL learn, but he's a creature of habit and his learning style is much more of a gradual build-up of understanding than a sudden 'aha moment'. If you follow the guidelines here, it will work out fine in the end, just stick with it.

It's a good idea to get your puppy neutered (or if you have a female, have her spayed) during this period, recommendations generally say it's best to do this before your pup is 6 months old. I agree with this for small or medium breeds, but as a big-dog owner, I prefer to go with somewhere around 8 - 9 months for these surgeries.

As large and giant breeds mature more slowly than their smaller 'cousins', 8 - 9 months is about right in my opinion.

However, I would suggest that you discuss this with your own veterinarian and come to a decision that you're comfortable with.

Seventh Stage: 1 Year and Beyond

As I mentioned above, there won't be much change in terms of physical growth or maturation for small and tiny breeds after one year of age.

But this 'slow down' won't happen for large and giant breeds until somewhere between 18 months and 3 years of age, so they will still be growing.

Gaining their full height first, then continuing to put on weight until they reach their full adult size.

In terms of behavior for large breeds you'll basically see more of the same teenage behavior, plus some noticeable growth spurts during this period of puppy development..

With guardian breeds this is when you'll start to see those instincts rise to the surface.

Pups of this age tend to be more combative with puppies or dogs of the same sex as themselves and during this stage of puppy development family squabbles may surface between dogs who have lived in the same house happily for months.

Many pups have no idea what to do with their guarding instincts when they first appear, and may try to act brave while hiding behind your legs. Again, normal and nothing to worry about. As your pup grows and matures these protective urges will mature with him and he'll learn the proper way to react.

NEVER, EVER encourage a pup to 'guard' or to act aggressively or defensively. That will confuse and frighten him and could cause a lot of problems later on. Be sure to correct him gently but firmly if he growls inappropriately though!

You can now switch your pup over from his puppy food to a premium dog food, as his nutritional needs are changing.

Your baby is an adult - at last! If you've spent time training and socializing your puppy and taken good care of his both his physical and emotional health, you can now breathe a sigh of relief! You have raised a happy, healthy and confident dog. Well done :)

At this puppy growth stage, they will start to open up their eyes and respond to sounds, light, and movement around them.

This is also when your puppy will eliminate without their mother’s help and their teeth will start to come in.

You will also notice a puppy at this point starting to get more mobile, although they will still tend to crawl instead of walking. They do, however, have enough strength to stand up, but will stumble a lot.

A puppy in this developmental stage will just be starting to recognize their siblings and mother. They may even take a lick of their mother’s food out of curiosity at this point but still don’t need more than mother’s milk.

When Do Lab Puppies Open Their Eyes?

Lab puppies open their eyes at about two weeks old. By this time, Labrador puppies will have their eyes fully open and most will be at least partly open. Ears open at this point too and your puppy will begin to hear.

Watch the video: 5 Essential Tips For 8-12 Week Old Puppies (July 2021).