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Stages of Growth: 12-Week-Old Puppy Behavior and Development

Adrienne is a certified dog trainer, former veterinary assistant, and the author of "Brain Training for Dogs."


What Are 12-Week-Old Puppies Like?

If you're planning on getting a 12-week-old puppy or have one already, then you're probably wondering if their behavior and development are within the norm for his age range.

12 weeks is usually the normal age for dogs to be sent home from the breeder. This mostly applies to smaller breeds. For example, Maltese puppies don't usually go to their new homes until they are 12 weeks old because they are still not fully developed, both mentally and physically.

Larger breeds, such as Labs, are usually ready to go to their new homes at eight weeks. If you purchase from a breeder, any puppy older than eight weeks may have been a singleton (the only puppy of the litter) or it was left over from a litter that has already been sold. Owners also sometimes return puppies to the breeder if they were not a good match. Of course, puppies may likely be older than 12 weeks if you go to a shelter.

Regardless, this article will cover almost everything there is to know when dealing with your new buddy. Normally, at this age, puppies are a handful, but luckily, puppyhood goes by really fast. You might even find yourself missing your pet's funny quirks.

This 12-week-old puppy has lost her lower incisors.

This 12-week-old puppy has lost her lower incisors.

12-Week-Old Puppy Development

At this age, they are only a fraction of what they'll be as adults. They have all the cute neotenic traits of younger puppies, but they are also a tad bit taller and longer, and their muzzles are starting to gradually lengthen.

Soft Hair

At this age, the puppies are still covered in soft hair that, fortunately, sheds very little. They will need a very delicate shampoo that is pH balanced. This is a good age to introduce the puppy to bathing. Be sure to make the experience positive and fun. You can also use dog wipes that are hypoallergenic and alcohol-free for cleaning in between baths.


Your puppy should have 28 baby teeth. It's still too early for them to get their adult teeth, which should come in within the next three months. Their teeth start falling out between the ages of 12 weeks to 7 months. They'll first lose their incisors, then the premolars, and finally the canines. You may find the occasional baby tooth in their water bowl. At three to four months of age, it's a good idea to have the vet check your dog's mouth to make sure there are no bite problems and that the teeth are growing normally.

At this stage of development, your pup will start chewing, and it's your job to find safe chew toys and treats that are suitable for his age. Puppy teeth are delicate, and an adult dog bone or toy may fracture them. Also keep in mind that their digestive system has not fully developed, so they will need easy-to-digest foods. I recommend Nyablone's Healthy Edibles and Nutri Dent Chews with the label "three-month-old puppy" somewhere on the packaging.

To help relieve sore gums, freeze a clean rag that's been soaked in water and wrung out. Chewing on this will soothe your puppy's gums. You should also get your dog acquainted with having his teeth brushed.

Better Bladder Control

This is a good time to start crate training. Generally speaking, you can expect a three-month-old puppy to be able to hold urine for two to four hours, depending on how much he drank and his activity levels. Some puppies at this age can also hold it through the night.


The first vaccine is usually given at six to eight weeks at the breeder, but your puppy will need another one at 12 weeks. This second vaccination will likely contain distemper, adenovirus, hepatitis, parainfluenza, parvovirus, and lepto. Lepto is generally given when a pup is 12 weeks or older and never before. The rabies vaccine is also given after 12 weeks.

12-Week-Old Puppy Behavior

If you are planning on adopting a puppy, make sure you puppy-proof your home to keep the furball safe and out of trouble. If you have ever had kids, think of this as the "toddler stage" when everything had to be safely stored away. But, unlike a toddler, your 12-week-old puppy will not be wearing diapers and will have sharp teeth. Here are some common behaviors of a dog that is three months old.

  • Boundless Energy: Your puppy will romp around and play all day. His gait is still quite clumsy, but he'll gradually be better coordinated. If you see your dog running really fast in circles, it is normal. They are just excited and having fun. Dog owners often call these the "zoomies." The good thing is that all of this activity will tire them out quickly and they will have no problem sleeping. Expect puppies of this age to sleep soundly for about 18 to 20 hours a day. The rest of the day is then spent playing, eating, and eliminating.
  • Curious and Adventurous: At this age, puppies are learning all they can about the world around them. In the wild, mother wolves encourage their 10 to 12-week-old puppies to use the den less and explore the great outdoors in special rendezvous areas, quite similar to open-air kindergartens. Domestic puppies also love to explore their surroundings, and often mouth objects just as babies do. This is why you should puppy-proof your entire home!
  • Possessiveness: Mine, mine, mine! Just as a toddler is not willing to share his toys with other toddlers, 12-week-old puppies go through a possessive stage in which they may have a desire to guard their food and toys against other dogs and people. In the wild, once out of the den, this instinct helped young pups from starving. However, in a domestic setting, you may want to nip this behavior in the bud by tackling resource guarding before it gets out of hand.
  • Separation Anxiety: Young puppies may throw a fit when they are left alone. It's important to gradually train your buddy to be alone. Try to avoid rushing to your pup when she is whining and crying. Rather, wait for her to calm down before you return to her. Doing so will teach her that calm behavior gets you back. Of course, before trying this method, make sure all your pup's needs are met. She may be whining because she's thirsty or needs to go outside to potty.
  • Socialization: At 12 weeks, your dog is in the full puppy socialization phase. This is the best age to take her to classes. Do your best to get her to meet different people, pets, and children. Organize puppy parties so your puppy has the opportunity to meet as many different people as possible. For safe socialization tips, visit the Operation Socialization website.

As you can tell, 12-week-old puppies go through a whole lot of growth and change! Enjoy this phase as puppyhood is very short.

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

Questions & Answers

Question: My nine-week-old Springer Spaniel bites a lot. What is the best way to correct her behavior? When we try, she barks and does it even more. She is very active, and is sometimes hyper.

Answer: It sounds like you have a very playful pup! I am not sure what you are doing to correct her, but it seems not to be working. Pups learn best if we take the time to show them what we want them to do rather than trying to correct them. It's a good idea to always keep a toy on

hand so that your puppy can transfer her attention to it. When she does, praise your puppy. You may also find it helpful to play these fun games with your puppy. While these are oriented towards German shepherd pups, any puppies may benefit from them:

© 2013 Adrienne Farricelli


Colleen Hayward on August 18, 2020:

Our 11 week old golden doodle puppy bites, growls & nips at us constantly. We try diverting her attention to a chew toy or putting her in her crate for a minute or two which seems to make her even more determined to bite. She is doing really well with potty training and sleeps through about 7 hours at night. She only sleeps about an hour or sometimes two during the day. We are desperate for help with the biting which is out of control.

Adrienne Farricelli (author) on June 02, 2020:

Hi Kara,

Your puppy is very young still. It could be he is stressed and hasn't been handled much. I would mention this to the breeder, just to give a heads' up. He needs to learn that hands are good through positive associations. Read this article on how to pick up a puppy and correct positive associations:

And look at the car wash game in this article:

Kara on June 02, 2020:

We brought home a labradoodle at eight weeks. We have three kids. He immediately started displaying aggressive behavior. The dog is nine weeks. Some examples: He was laying at my husband’s feet and my husband tried to pet him and he growled. Sometime when we pick him up he growls, snapping bark and turns his head to bite our hand. This happens daily and outside of play mode. HELP!

Adrienne Farricelli (author) on May 09, 2020:

Short of having some orthopedic problem, this behavior may have to do with fear. See if these tips may help:

Rita on May 09, 2020:

My 12wks golden doodle does not like going out ,he sits down even when i offer treats we have had him since 8wks he is perfect in every way but for walking outside .

Mary on February 27, 2020:

My goldendoodle is 13 weeks old and started mouthing and now biting me. She nips at my pant legs and feet. She growls and bites when I tell her NO. Any HELP?

Pinkgirl1947 on February 15, 2020:


This site is so informative as we have just got baby sitting duties for our sons 10 week old staffie cross who is so cute but needs some of this advice instilled in her lol

Adrienne Farricelli (author) on January 04, 2020:

Hi Steph, welcome to the puppy nipping stage! This is for German shepherds but it may work well for your dog too:

Steph on December 30, 2019:

Bought a staffy pup 4 days ago and she keeps lunging and biting hard. Any advise?? Thank you

Danielle Davison on December 03, 2019:

Diana - watch Zak George videos on you tube! That’s not the most effective way to change your dogs behaviour!

Adrienne Farricelli (author) on November 25, 2019:

Hi Bunts,

Some breeders prefer to send their pups to good homes when they are 12 weeks considering that puppies go through a fear period from 8 to 10 weeks.

Bunts on November 24, 2019:

Hi have a qts planning to get a golden doodle and he’s 12 weeks old is this the right age to get it or younger is better plz let me know tks

Adrienne Farricelli (author) on August 27, 2019:

It sounds like he's tentative in approaching and has mixed feelings. In cases as such, it often helps to not have people go to pet him directly or loom over him, but have your dog approach them on his own. Having the people sitting versus standing often helps too. One trick of the trade is to have people toss treats to your dog, but past him rather than to draw the dog. Here's a read about this method:

Katie Ryan on August 20, 2019:

My golden retriever puppy is now 3 1/2 months old and when people go to pet him he backs off,but he still tries to go over again with his tail wagging.Hes fine being petted by certain people,most of the time when they have a dog.I was wondering if this is normal for his age or will he grow out of it?I know his tails wagging but could he still be anxious about being pet and how would I work on it?as my other dog has always been fine with people.

Adrienne Farricelli (author) on August 13, 2019:

Diana, I feel that rather than anger, your puppy uses the crate as a bathroom due to anxiety. She wants to be with your other dog and her family and this creates great distress. You cannot really "correct" your puppy for how she interacts with your border collie. At 11 weeks she is only socially illiterate, and her behavior is just boisterous, normal puppy behavior. Just like toddlers are impulsive and don't have manners, puppies don't have much impulse control and act out instinctively. Your border collie may be granting her a ''puppy license" and letting her get away with things because she knows she's just a puppy. At some point, she may decide to correct the puppy as the puppy matures more, but chances are, if they are both females, there may be squabbles or even serious fights along the road.

Diana on July 09, 2019:

My 11 week old English Setter puppy is extremely brave and

Dominant She wants to be in control of my two-year-old border collie mix when I correct her by putting her in her crate she gets even more upset and barks and cries the entire time and will use the crate to go to the bathroom, I feel she’s doing it out of anger because she sleeps in her crate all night and does not use it for the bathroom. How do I correct this?

Joy on January 21, 2019:

My 12 week old German shepherd will hide all day and not want to play or walk. It’s beem 3 weeeks now since we got him and he hasn’t changed much at all...

Em on October 14, 2018:

My 12 week old lab is awake ten hours a day

Pam Como on September 23, 2018:

Most informative site. Answers a lot of questions about our 12 week old.

Ave on June 07, 2018:

Very informative, many questions answered although, mines is 9 wks insight was helpful.

Kimberly Bracken on June 04, 2018:

I am getting my pup in November He will be 12 weeks the lady I am getting him from breeds boxers in Cannon Falls I have a 3 year old cat that I have had since she was 3 MONTHS old How can i teach them to love each other.?

Lynn on July 24, 2017:

Enjoyed reading about young pups.

I have a 4 month old Labrador her energy level is virtually limitless the only problem I get is her teeth sink into my hands and arms no amount of saying no biting helps hopefully she will grow out of it.

Thanks again for your much appreciated knowledge.

Donna on July 19, 2017:

Very interesting

Adrienne Farricelli (author) on April 22, 2013:

And the puppy stage is just so short! Puppies are the cutest things!

Jennifer Bart from Texas on April 22, 2013:

Great hub! Very informative and well organized. Reading this makes me miss my dogs puppy stage! I really enjoyed reading this.