Puppy Development Stages And Growth

When you have a litter of pups that have just been born, sometimes it’s helpful to know what’s happening while they grow. If you own these puppies, you need to know what to do for them and when. 

The best part is, if you know what you’re doing, you get to watch these adorable little things grow into the precious pets that love to tear up your furniture!

There is a lot of information about the growth of your pups. So we’ve divided those into a number of small parts.

Importance of Growth and Development

Puppy development and growth is important to pay attention to and know about because they have certain care needs for different stages. 

If you raise it a certain way, your pup will have a head start to leading a graceful, successful life.

Newborn Pup Care

Neonatal puppies have unique and specific needs for care that you should make sure you’re doing.

1. Nutritional Information

For the first couple of weeks, you can leave the feeding up to the mama pup. You should keep track of its weight, talk to your vet about the right size for your specific breed.

You should check weight at 12 hours, 24 hours, 48 hours, 3 days, 5 days, and 7 days, according to Dr. Klein of AKC. If you notice it’s underweight along with other symptoms, it may be malnourished.

2. Healthy Start?

In general, there are things you can look for to see if you’re pup is healthy. If they have healthy fur, no problems feeding, properly working digestive functions, and moist, pink gums then they are probably fine.

Check with your veterinarian to know exactly how to know.

Neonatal Stage: 0-2 Weeks

Right after it’s born, the puppy enters the neonatal stage that lasts a total of two weeks. Dogs in this stage are referred to as neonates.

1. Changes

There are a few important things that occur in this stage that you should look for. If the puppy is experiencing all of these, it’s on the right track.

Missing Senses

Right after birth, puppies lack the ability to see or hear anything. This loss of hearing and vision leaves them with only ⅗ of their senses.

Pain Recognition

Though they lack a couple senses, they don’t lack the ability to feel pain. If they’re whining, take it as an, albeit annoying, good sign.

All Sleep, All Eat, All Day

During this stage, you should notice the little ones spending most of their time asleep or eating food. Sleep helps the body develop, and food gives them the energy for the processes occurring during development.

Body Temp Regulation

Newborns can’t regulate their body temperature that well, so it’s up to the owners to ensure they aren’t exposed to any drafts or things of the like. Not only do cold temperatures cause stress for the puppies, but also increases the possibility of disease contraction. 

Well-placed heat lamps are a good way to keep the little ones warm until they can start to control their body temperature.

Waste Issues

It’s not news that newborn puppies, of many species, can’t do some basic functions on their own, right away.

2. Care

The physical limitations that the puppies have during the neonatal period calls for certain needs of it during this period.

Mother Dependency

Since the pup can’t expel waste on its own as well as its need for nutrition means the mother has to provide both of these throughout this stage.

Human Replacement

If, for whatever reason, the puppy doesn’t have its mother with it, the human owner has to step in to fulfill those motherly duties.

This means helping the pup eliminate waste as well as be fed. Also, some form of heat need to be supplied from the human to the puppy.

Warm Habitat

There are different ways to keep the puppies warm in the neonatal stage. The simplest would be a heat lamp, but in reality they just need to be kept at 80 degrees.

Try to stay away from heating pads, as they present a risk of burning the small dogs.

Check for Worms

Around 2 weeks, you will want to go to the vet to check your puppy for worms. They are a very common issue among dogs and it’s always good to be sure.

If they do have worms, you can get medication to eradicate the problem.

3. Vet Visit

It’s important to have check ups with the veterinarian to make sure everything is going well, because they’re the experts.

You can read all the blog posts you want, but the only one who will be able to confirm anything for you is a vet.

Birth Defects

You especially cannot figure out birth defects at home, they need to be checked for by a veterinarian. On the day of or after birth, bring them in for a screening to check.

Related Reading: How To Take Care Of Your New Puppies?

Puppy Transitional Stage: 2-4 Weeks

After a couple weeks of being alive, you’ll notice the puppies undergoing some new changes. This signifies they have progressed onto their second 2-week stage, the transition period.

1. Changes

This new stage brings about a new set of significant things to look for. This is how you now your little one is in the right stage for the timeline.

Senses Regained

During this period, the pup starts to develop the senses it was missing in the first couple weeks. Vision may start out impaired, but will improve with time.

The sudden onset of sound may also startle the puppy, causing it to jump when hearing normal to loud noises.

Solid Food

Their mouths are still composed of a lot of easily damaged soft tissue with little to no teeth. 

Pups, however, may still be able to eat mushy solid foods by the end of this stage, as long as they don’t damage the gums and if teeth have started to develop.

Information Gain

This stage brings about a lot of learning as far as the puppy is concerned. It starts to figure out how to do things on its own, without the help of its mother or owner. 

Social interaction, although minimal, begins. Crawling also begins as the pup is learning how to get around on its own. The addition of the two senses also allows the young one to observe a lot more in these two weeks than the previous two.

First Steps

As they start trying to get around on their own, it’s likely they make their first couple steps in the later end of this stage. This is the beginning of their ability to walk/crawl around.

2. Care

These new characteristics bring about new specific care needs for the dogs that fit the changes.

Warm Habitat

Body temperature regulation doesn’t start to develop until the end of this period, so there should still be assistance with that until about 4 weeks of age.

Social Butterfly

As they become aware of their surroundings, they start interacting with the other animals around them. This includes other pets, the mama dog, or even humans.

Time to visit the vet

3. Vet Visit

Just like at any stage, if you have any questions or concerns that could be important, contact your veterinarian to be safe.

No Visit

If you’re puppy seems to be developing normally and on schedule, you probably don’t need to get a check up during this stage.

Puppy at 3 to 4 Weeks– Awakening of Senses

1. Changes

As the puppies develop, they start to become aware of their environment. They realize humans are different than them and that they are stronger or less strong than certain other animals.

Human Difference

Since their awareness has been heightened, they start to realize that there’s an underlying hierarchy between animals, and that humans are above them on there.

A Lesson in Manners

Just like they become aware that humans rank above them, their mother lets it be known she ranks above them as well. By doing so, she is able to direct and teach them proper mannerisms.

Play Fights

With socialization, come friends. As the puppy starts to make friends with other pups, they may start to play fight. This is because they are wound up with energy and feel comfortable enough with each other to mess around and get some of that energy out.

They are also starting to form a bark at this age, which they will express during this play fighting.

Two Food Sources

With the development stage of teeth, not only are they able to but it is beneficial for tooth growth for the puppy to start eating kibble.

They are not going to be weaned at this age, however, as they are still receiving necessary nutrients from their mother.


The more the pup starts to intake, the more sensations of need to release will occur. During this stage, they will likely start to eliminate by themselves, though the mother may clean the mess.


The more they move around, the less clumsy they are while trying to walk around. As the weeks progress, they will be more stable and may start dexterously running through the house.

2. Care

There aren’t many difficult needs for care in this timeframe. This is a time for them to get acclimated to everything around them and start to really understand how everything works.

New Sounds

To help teach the pup the meaning and significance of certain sounds, repeat them to the puppy multiple times in combination with other visual memory stimulants like objects.

Subjecting them to loud noises will also help with removing the flinching instinct.

New Textures

Just like learning sounds, learning textures is important for puppies to learn how they can safely walk or run on certain surfaces. 

This is how they learn to not run on the tile because, if they do, they will slide into the side of the counter when they try to stop.

Check for Worms

At four weeks, you want to be safe and take the puppy in to check for worms again. If they’ve contracted some since the last screening, treatment should be started.

3. Vet Visit

There’s a few important things that you should consider about your dogs veterinarian care while growing up and developing.

Clinic Friends

If you don’t want your furry friend to be nervous every time it needs a check up, get it to bond with with staff at your clinic. 

Using treats to familiarize the dog to the staff will cause them to be more willing to go in for appointments.

Handling Exercises

If you want everyone’s life to be easier when trying to handle your dog for any reason, you’ll want to do handling exercises.

This gets them use to you touching their paws, ears, mouth, or anything else.

Trimming their claws, looking in their mouths for foreign objects or dental health. And so many other things will cause much less of a headache.

Positive Memories About the Vet / Clinic

You really don’t want your puppy to associate the clinic with negative memories, as they will be less likely to want to go back.

This can cause problems in the future which most people would want to avoid. Just try to make your little one happy before you leave to get it to associate good memories with the clinic.

Clinic Aversion

Frequency of your clinic trips also helps to make sure the dog treats it as a familiar, friendly place. 

If they learn to not like the visits, it could be difficult to work with getting them to cooperate while going.

Puppy Socialization 4-7 Weeks 

1. Changes

At this point in time in your puppy’s growth, it starts to mature. The discipline its mother has been giving it has started to take effect.

This means they are able to start learning discipline from humans. Now would be a good time to start teaching the pup commands.

Hello Teeth

Watch out for teeth to start pushing beyond the gums. This is the start to a lot of new experiences for your dog.


Your pup should be wandering around and following smells out of curiosity. They will try to seek out new things to experience.

Puppy Mates

In this stage, your puppy will start to socialize a lot with the other animals around. Make sure you allow them to run out their energy during these weeks.


The hierarchy they learned when they were younger shifts during this time to change periodically. If you own two or more dogs, it’s entirely possible that your puppies will switch the dominant role back and forth.


Though they may have been eating solid dog food for a couple weeks or so by now, it is finally time to start weaning. 

It is important not to wean too quickly to make sure the pip gets all the necessary nutrients.

Shots Round 1

At around 6 weeks, your dog can get three different shots. Distemper, measles and parainfluenza vaccines. You may also get the Bordetella vaccine.


Due to the curious nature of puppies this age, they may often get distracted causing them to wander away from whatever it is they were doing before.


Part of the maturation of the pups at this time includes their awareness of what they are allowed and not allowed to do. 

They also will start learning to correct bad behavior more quickly with assistance from the owner.

Mother’s Away

In addition to the puppies learning as they grow, the mother dogs add to the maturation by leaving the little ones alone for longer periods of time.

This gets them more used to being alone for longer periods of time.

2. Care

A lot of progress is made during this stage, which means a lot of guidance to make sure they stay on the right track.

New Experiences

Since your puppy is so curious now, indulge it by taking it out to do new things. These new experiences will help give something for the little one to focus on and process.

Separation Anxiety

If your furry friend is always around you or other furry friends, it may get too used to being around other animals and develop an unhealthy attachment.

This will cause them to get anxious and upset when left alone.

Dogs and Humans

Since this is a time of maturation, this is the optimum time for them to get human contact to learn how they should interact with humans.

Quality Food

The less a pup is nursing, the less nutrients it is gaining from the milk. As puppies start to nurse less as they start growing teeth, they need high quality dog food that is rich in the nutrients your puppy needs.

First for Everything

This stage, in general, is a good time for first experiences. Try taking it out for its first ride in a car of clean them off in a warm bath for the first time. Anything to give them a new memory.

Not Quite Yet

While they are working on being independent, they aren’t ready to be completely on their own yet. Socialization is still good for them, and being alone so quickly may cause stress.


All of these new occurrences will add together to give your puppy a new knowledge base and, hopefully, moral compass.

3. Vet Visit

Your veterinary care routine shouldn’t be much different at all from the previous stage. Just make sure they keep liking the vet!

No Visit

Chances are you’d be okay not going into the clinic if you don’t believe the pup needs it.

Unsure About Vaccines?

At 6 weeks, if you decide to get any or all of the acceptable shots previously mentioned, you’ll want to confirm with your physician first.

Stool Sample

Intestinal parasites are a nasty occurrence among dogs, and you’ll want to pay close attention to make sure your pet doesn’t get any.

If you suspect anything, talk to your veterinarian and they can take a stool sample to test.

Food and Nutrition

It’s important to stay informed about what your dogs needs to eat to be healthy. Especially when they’re going through so many nutritional changes, like weaning.

Bonding Exercises

Handling exercises are a good way to, not only bond with your dog, but to get it more comfortable with humans. This will make human interaction a lot easier for them in the future.

Puppy Socialization and Fearful: 8-12 Weeks

Puppy Feeding Schedule The Ultimate Guide

1. Changes

This stage is a very noticeable juvenile period of change in your puppy in which you will see a large difference from the beginning to the end.


Now the clumsy, puppy charm is starting to wear off, and your pup should be getting pretty graceful.


While before you may have noticed your pet wandering a little ways off when they got distracted. 

Now, they will leave the room without any warning at all, because something got their interest. Yes, even while you’re petting them!


Fear becomes a big part of this developmental stages. The puppy becomes overly cautious, and stressful and traumatic situations can permanently affect your pet.

2. Care

8-12 weeks in, the needs for care slow down a little bit. As long as you know how to keep your eye open for anything harmful to development, you should be fine.


To avoid permanently affecting your dog, stay away from loud, stressful situations. Keep in mind their heightened sense of fear.

Keep An Eye Out

As they get more curious, puppies tend to wander places they’re not supposed to. Try to keep an eye on your pet when outside, don’t let them go too far.

Shots Round 2

The second round of shots, usually given around 10-12 weeks, consist of the DHPP. It is a combination vaccine for various viruses and such.

Health Risks

Round two was not the last, and it’s wise to keep that in mind. You probably don’t want your puppy hanging around other dogs who have the ability of transmitting something your pup isn’t vaccinated for.


Right now, your puppy has just learned everything to be able to be efficiently trained. If you plan on rehousing it at any point, do it now. Make sure they start training right away!

Repeat the Name

One of the most important things to keep in mind while training, is to say your pet’s name. This is the easiest time for them to learn it, and if you keep saying it they will eventually catch on.

Dog in a vet

3. Vet Visit

Now that so much has changed with your furry friend, your clinic visits need to update a little bit.


Your dog is growing quickly now and needs energy, so give them positive reinforcement and a snack by giving them treats throughout the visit.

Talk to the Staff

You want to keep the friendly human interaction going, so ask the clinic staff to work with the dog on social skills and handling exercises.

Clipping Nails

There is a wrong way to cut your pet’s nails, and it can really harm them. Check with you veterinarian on how to properly cut before doing it yourself.

Dental Care

If you want to avoid problems like bad dog breath, drooling, and discolored teeth on your little pup, talk to your physician about how you can get ahead on taking care of its teeth.

Read More: 18 Super Tips For Puppy Dental Care

Happy Memories

As your dog gets older, their interests start to wander. You want to keep them interested in going to the clinic by making it fun for them with toys and treats every time before leaving.

No Visit

These are all recommendations, but if you believe your pet is healthy, there’s no reason for you to have to take them in.

Muscle Stimulation

Handling exercises can also help stimulate muscles that don’t get used very often. While doing the exercises, focus on those weak spots like the hind legs.

Puppy at 3 to 4 Months-The Puppy Juvenile Stage

After your puppy has completed the neonatal stage, he will move on to the juvenile stage. The juvenile stage typically starts at 3 months and only lasts for about a month.


This stage is very important in your puppy’s development. You can think of this as the stage where a newborn baby transitions into an infant.

Puppies Go To New Home

Once a puppy reaches the juvenile stage, they are officially ready for adoption, if you choose to do so. This is the age where your puppy should have learned enough to be efficient with future training.

Past the Fear Stage

By this time, your puppy should be a little more comfortable with the outside world. He will not be as frightened by people or objects.

Just remember to keep him away from things that may continue to traumatize him. In other words, it still might be a little too early to introduce him to the vacuum cleaner.

No Longer Spoiling in His Bed

Before the juvenile stage, your little guy might have a tendency to relieve himself right where he  sits.

Now that he is getting past his neonatal days, he may start getting out of bed to go “mark his territory”, although sometimes it may still be inside the house.

My Dog Ate Plastic

Puppy Continues to Cut Teeth-Chews on Everything

As with human babies, puppies also go through the teething stage. His teeth should continue to be cutting through at this time. 

To help move the process along, he may start chewing on anything and everything he possibly can.

It could be toys, furniture, or even you. But don’t worry, it won’t cause any damage at this age.


Puppies hitting this stage don’t have as many needs as he did in the neonatal stage, but he still requires a little training. 

He is now more aware of his surroundings, but it is still important to continue making him comfortable with the outside world.

Socialization Training

This is the time where it is important to introduce your pup to other dogs and people, now that his fears are starting to decrease. 

Don’t move too fast though. Calmly introduce him to new beings so that he will be comfortable with socializing.

If you are introducing him to other canines, make sure they are not vicious as it may traumatize or result in injuries to the little guy.

Potty Training

This may be one of the more difficult aspects in training. Your puppy is now starting to use the restroom in other places besides his bed. 

It is important to introduce him to puppy pads. Once he starts sniffing around to find a place to go, quickly pick him up and place him on the pad.

This will show him that there is a designated space for him to relieve himself. If he needs more motivation, try giving him a treat every time he uses the puppy pad.

Chew Toys

Since he is still cutting teeth and chewing on everything, get him some toys to chew on. This will get him out of the habit of chewing on other things, like furniture.

Puppy Classes Begin

If you have a nearby pet store, such as PetCo, you may learn that they sometimes offer puppy training. It does cost a bit of money, but it’s less work for you!

Veterinary Care

In the juvenile stage, it is important that your puppy gets regular vet visits to keep track of his progress and keep him in good health.

Rabies Vaccine

Preventing rabies is one of the most important choices for your puppy. This is highly recommended for a puppy at this age.

Possibility of Stool Sample

Veterinarians may need a stool sample to diagnose any health issues in your puppy, such as parvo or heartworms.

Preventing Heartworms

Heartworms can be very hazardous for your puppy. There is treatments that can prevent them so they are also recommended. If your puppy has heartworms, you will find them in their stools.

Puppy at 4 to 6 Months The Ranking Period

This is the preteen stage for your pup. It may be similar to the preteen stage of humans. They are continuing to grow and learning more about their surroundings.


Here are a few things to look for when your little guy hits this stage.


At this age, your furry guy may want to explore a little on his own. This would be a great time to make sure there is nothing within reach of him.

Just like babies, once they start exploring, they may try and chew on anything they come across.


Now that he isn’t a newborn puppy anymore and is getting older, this is known as the “preteen” stage because it is the point between being a baby and well, a teenager.

“Big Dog” Attitude Begins 

Of course, you come to find out teenagers tend to have attitudes making them feel like adult dogs. Canines work the same way. You may notice your little guy trying to act out and begin to think he is grown.


Even at this slightly older stage, your furry friend still has important needs to keep him strong and healthy.

More Socialization​​​​​

This is the period where you should have “play dates” with other dogs to continue to make them more comfortable with being social.

Continue Training

Although he is no longer a baby, he will still require training. Be stern with the potty training and attitude adjustments.

Have Patience

Even though you need to be stern, you can’t expect him to become a professional at everything he learns on the first try. It may take a few practice rounds before he gets it.

Veterinary Care

Continue to take the pup to the veterinary clinic to be certain he is growing like he should and make sure he hasn’t gotten any health problems.

Handling Exercises

This is the perfect opportunity to train him how to properly respond to being on a leash. Take him for walks and let him know what is right and wrong. It is also great to continue his potty training.

Comfortable at the Vet

When you take him to the vet, make sure you console him if he starts getting anxious. To comfort him, just calmly talk to him and pet him to reassure him that the veterinarian is there to help.

Puppy at 6 to 18 Months: Adolescence

This is the stage people may worry about. It is the point between being a preteen and puppy growing into an adult dog.


Some things to look for when he gets to this stage are as followed.

Begins at Adolescence and Ends at Sexual Maturity 

This is where your dog starts to explore other dogs physically. This is known as post-puberty. Your not-so little guy is now attracted to dogs of the opposite gender.

Independence and Stubbornness

Now that he has hit this age, he may want to be a rebel. He will try to run off on his own and might react resistant when instructed.

Second Fear Stage

Since he has been exploring more, there may be some changes. He can develop a sense of fear once again, especially if he experiences a traumatic event.

Female Heat, Male Testosterone

For female dog, hitting puberty results in going into “heat” which is commonly considered her menstrual period. She will be very feisty and possibly very attracted to the male dogs.

The males will sense this excitement and try to involve himself with her.

If you don’t want to have another littermates, don’t worry. This is also a good stage to have your dog spayed or neutered which we will discuss in the next segment.

Goodbye Baby Teeth, Hello Adult Teeth

At this point, he will lose his baby teeth. He may or may not continue to chew on everything. It depends on what makes him feel more comfortable.


Now it’s time to talk about the important things to do when he is reaching adulthood.

Continuance of Training and Reinforcement of Rules 

Since he is going through his stubborn age, you will need to remind him of what is right and what is wrong. 

Keep taking him on walks to continue teaching him about social interaction and potty training.

Neutering or Spaying

As I previously mentioned, this is the perfect time to get your canine spayed or neutered if you don’t want to breed. You may be wondering what the difference between neutering and spaying is.

Spaying is the surgical removal of a female animal’s ovaries and uterus. Neutering is the removal of the male’s testicles. 

To avoid pain and discomfort during the surgery, your dog will be under anesthesia so they won’t feel anything. After the surgery, your dog will most likely be sore.

The surgeon will suggest giving your dog a protective “cone” around the neck and face to prevent your dog chewing on the surgical area.

Transitioning to Adult Food

Now that his adult teeth are coming through, it will now be easier for him to chew adult food. 

When transitioning, you should mix a little bit of adult food with a little bit of puppy food to avoid an upset stomach.

Veterinary Care

Proceed taking him to the vet to continue discussing possibilities of protective actions.

Discussing Spaying or Neutering

If you choose to spay or neuter, talk to the veterinarian about the pros and cons of the surgery so you will have a general idea of what to expect.

Consider Micro-Chipping

Micro-chipping is the insertion of an electronic identification device. The chip is about the size of a grain of rice. When detected, it will give information to someone who finds your dog if he gets lost.

It is implanted between the back of the neck and the shoulder blades, just under the skin. Each chip has a number specifically assigned to your dog that can be detected with a microchip scanner.

Possibility of Stool Sample

This is another time to ask the vet about a stool sample to reassure your dogs health and continue to make sure he has not contracted any sicknesses.

Puppy at 1 to 4 years

Your dog is now officially a mature adult. He has learned so much in the past few years, but still goes through some changes.


Once he is an adult, here is some information about his increased maturity.

Social Maturity

Now that he has grown into an adult, he may be fully comfortable playing with his doggy friends. He has learned how to react to the outside world and how to handle social situations.

Timing of Maturity 

Within these years, he has learned the difference between right and wrong. He is now very intelligent and mature.


Even as an adult, you should still be aware of his needs. One important recommendation at this age is getting a crate.

Crate Recommendations

A crate is a comfortable crate to invest in for him to sleep of travel in. A good crate is both comfortable and spacious. It should be big enough for your dog to move around a little bit.

Some dog owners put blankets or pillows in the crate so the now big guy has some comfortable cushion to lay on.

Veterinary Care

It is still vital that you continue to take him to the vet for check ups.

Yearly Checkup and Possibility of Stool Sample

Once they get to this age, they won’t need to go to the vet as often as before unless it is an emergency. 

They will now just go for their annual check up to continue checking for everything regarding his health, still possibly requiring a stool sample.

Possible Hip Dysplasia X-Ray

Dogs at this age are now getting old and may begin to have joint pains. One of the most common conditions is hip dysplasia which will require x-rays to diagnose. 

This is an abnormal genetic trait often affected by environmental factors that will eventually cause crippling and severe arthritis of the hip joint.

Sub-Phases of Socialization Period

The socialization period that occurs between about 5 weeks and 16 weeks is divided into two phases. The first phase is primary canine socialization and the secondary is human socialization period.

This period is when your puppy is forming social relationships. First, he should be introduced to other dogs to feel at ease. Next, it is important to introduce him to humans so he will know how to respond.

Curiosity- 5 to 7 weeks

Curiosity begins when your puppy is approximately 5 weeks old. This is the first step in introducing him to others. This is highly recommended before rehoming your pup.

Behavioral Refinement- 7 to 9 weeks

The beginning of the socialisation period is to see how he reacts with the outside world. There is no guarantee that he will be comfortable the first few times you get him adjusted to new sights and sounds.

Fear Imprint and Impact- 8 to 11 weeks

The key to puppy socialization is not to overwhelm him. Its natural for him to be scared when he experiences something new for the first time.

His fear may be shown by shaking, whining, tucking his tail, or trying to hide. It is important to keep the interaction as pleasant as possible.

Environmental Awareness- 9 to 12 weeks

Be sure to take him to a clean and unrisky place. If he is not yet vaccinated, unhealthy environments can cause illnesses. Also, keep him on a leash if there are large groups of people and animals around.

Classification of Seniority- 13 to 16 weeks

Around this time is when your puppy will try to establish dominance. He may begin to playfully bite you to challenge your authority. Be sure that if he tries to aggressively test you, always discourage it.

You can try playing tug of war with a toy to safely establish that you are indeed the leader.

What Are Puppies Like at 12 weeks?

At 12 weeks, your puppy is rapidly growing. He will be more curious about his environment. He will have better bladder control at this age with proper potty training.

Puppy behavior, however, can vary. He may be calm, hyper, fearful, or aggressive. It is important for him to have positive experiences in order for him to be comfortable.

12 Week-Old Development

If you’re planning on adopting a 12 week old puppy, you may wonder what aspects he is developing.

Soft Hair

Since he is still very young puppy, his hair will still be soft like it was when he was a newborn. He probably won’t shed very much. Be sure that you use a pH balanced shampoo when washing him.


Before he gets his adult teeth, he will have first obtained his 28 baby teeth. This is the age where he begins losing his baby teeth.

You may even find a baby tooth in his food bowl that might have fallen while he was eating.

Make sure to get him to chew toys and age-appropriate treats for him to chew on to speed up the teething process and make it more comfortable.

Better Bladder Control

During this time, he won’t have as many accidents as he used to. He may be able to hold his bladder for 2-3 hours at a time, depending on his liquid intake. This is perfect for potty training to begin.


He should have had his first vaccine between 6 and 8 weeks but will need another one at 12 weeks.

This 12-week vaccine should contain distemper, adenovirus, hepatitis, parainfluenza, parvovirus, and lepto.

This is also the time when he should get the rabies vaccine.

12 Week-Old Behavior

Aside from physical development, he will also go through behavioral changes during this short period.

pitbull Terrier Dog Breed Information, Pictures, Characteristics & Facts


Puppies at this age will most likely want to run around and play all day. He isn’t quite coordinated yet so don’t be surprised if he stumbles around and is clumsy.

Curious and Adventurous

This is  definitely the time to puppy proof your home as he will now be learning about the world around him and wanting to explore. 

They may try and get anything and everything in their mouths just like human infants.


Puppies will probably go through a possessive stage where they desire to guard their food and toys against other dogs and sometimes humans.

Separation Anxiety

Puppies, just like babies, prefer to not be alone. If you leave him by himself, he may begin to whine and cry to get your attention. 

Instead of rushing back to soothe him, give him a little bit of time to calm down and try to self soothe.

Most of the time, he will whine because he is thirsty or need to go potty. Sometimes, it may be because he is scared.


Around this time is when your pup will be in full socialization mode. This would be a good time to enroll him in training classes, and introduce him to other dogs and people.

Puppy Development Questions

I often receive questions about puppies from some of my curious readers. I have decided to publicly answer the most common questions below.

How can I tell how big my puppy will get?

It isn’t clear how big he will get because different breeds grow at different rates, and even each puppy of the same breed will vary in size.

A common myth is that you can look at the size of his paws to predict how big he will get. Unfortunately, there are really no reliable methods to determine this.

What are the differences between male and female puppies? 

Aside from anatomical differences, such as their “private parts”, another difference between males and females is weight.

Males of the same age and breed as females are usually a little heavier. It is more noticeable in the larger breeds than the smaller ones.

How does neutering or spaying affect growth?

Neutering or spaying your dog affects the final size of your pup. The dogs sexual hormones are involved in telling the body to stop growing.

A dog that undergoes these surgeries before they stop growing may still continue growing longer because they now lack the hormones to switch off their growth.

When do puppies open their eyes?

Your puppy will fully open his eyes during the second week of puppy’s life. Unlike human babies, puppies don’t immediately open their eyes after birth.

Every few days, his eyelids will have a tiny gap so you may notice him peeking through before they open completely. Don’t be alarmed if one eye opens faster than the other, this is normal.

When do puppies start walking?

Your puppy will probably get up on his legs around the third week. Usually by the end of the third week, he should be standing up and taking a few wobbly steps.

What are the puppy socialization stages?

Important key phrases to be aware of are the windows for socialization and the teenage fear period.

The window for socialization closes around three months of age. This is the time when he will accept and adapt to his surroundings.

During this phase, you should take him everywhere and let him experience as much of the world as he possibly can.

The teenage fear period happens between 6 and 12 months. It is when puppies that were completely social become fearful again and should be reminded how to react.

Best Dog Foods For Husky

What age do puppies become adults?

Determining when he will be grown up depends on the breed. He will go through three stages before he is really considered an adult. These stages are physical maturity, sexual behavior maturity, and mental maturity.

He needs to reach all three aspects of maturity before he is an adult. Again, depending on the breed, these stages may not all happen at the same rate.

When do puppies stop growing?

Physical maturity is reached at different ages in different breeds. Smaller dogs tend to stop growing much sooner than big dogs.

Neutering and Growth

Neutering may not only affect the growth hormones in your dog but might also affect his appetite. However, this is not always the case.

Sometimes, a dog may begin to eat less after the surgery, but other dogs may not be affected at all.

How much should my puppy weigh?

Of course, weight depends on age and breed. There are 5 categories of breeds. Toy, small, medium, large, and giant

Toy dogs are generally born with a weight of about 6 ounces. They stop growing once they reach between 6 and 7 pounds which occurs around 8 months.

Large dogs are usually born about 1 pound and stop growing around 18 months at a final weight of about 75 pounds. 

Giant dogs are born even bigger than large dogs and continue to grow until about 24 months weighing around 150 pounds.

Is my puppy too thin?

The few ways to tell if your puppy is too thin vary. If he is under 6 months old, you should not be able to see his ribs. However, you should still be able to feel them as they should have a layer of fat covering them.

Your puppy should also have a waist which should go in just before his hips. Also, look at your puppy from the side.

His tummy should gently slope so that his tuck is the highest right before it disappears between his hind legs.

If you can see his ribs, feel the bumps in his spine, or see his hip, he is too thin. You can increase the amount of food he eats daily. You should do this by adding an extra meal instead of making his meals bigger.

Guide to Healthy Puppy Weight

If your pup is the right weight, you should be able to check off four things. If his ribs can be felt but not seen, if he has a waist, and if he has a tuck, he should be weighing just fine.

Mental Maturity: When will my puppy calm down?​

Even if your puppy is both sexually and physically matured, he will still be a puppy until he is mentally matured. Until this happens, he may continue to be silly and excited for about 2 years until he reaches mental maturity.

People Also Like: 4 Interesting Facts Why Your Dog Needs An Orthopedic Bed?

What Stage Is Your Fur Baby In?

I hope you enjoyed this insight into puppy growth and development. Feel free to leave a comment with stories or more information you wish to add to this.

I would love to know what phase your puppy is going through and what milestones he or she has achieved!

Further Readings:

Other Puppy Adoption Related Topics:
1. Hypoallergenic Dog Beds For Keeping Your Dogs Allergy Free
2. How To Pick Best Dog Beds For Boxers?

Leave a Comment

Your email address will not be published. Required fields are marked *