Puppy Development and Key Milestones in the Journey from Puppy to Dog

Puppy Development and Key Milestones in the Journey from Puppy to Dog

Posted: 06/23/2022 | Categories: Dog Behavior

It’s so exciting getting a new puppy, but do you know what to expect as they grow? It’s important to understand how your puppy will develop so you don’t expect too much from them too early, and you introduce new experiences at the right time for them.

Studying a few puppy training books will help you to plan your first year together and learn how to bring up a well-behaved dog, and here’s a summary of what to expect to get you started.

Newborn – 2 weeks old 

Your puppy is completely dependent on his mom, just able to suckle, sleep and crawl around enough to find warmth and food. His eyes open at around 10-14 days old but vision is poor initially. A small amount of very gentle handling to check him over is all that’s needed in this period.

Transitional period 2-3 weeks old  

Your puppy’s mom is still hugely important influencing behavior. His hearing and sense of smell develop and he starts to get his first teeth coming through. He learns to walk and lap water. Conscientious breeders will pick up the pup each day to check they are gaining weight and developing as they should, and to get them used to being handled a little.

Socialization period 3 – 12 weeks old

You will probably take your new pup home at 8 weeks old, or perhaps slightly more. It’s crucial during this phase of development that your pup is socialized with people, other dogs, the home environment with its noisy machines and comings and goings, and the great outdoors. Your breeder should start this process.

Stage 1: 3-5 weeks old

By this age your pup can see, hear and smell pretty well. He starts to eat solid food, wag his tail, bark and play with the other puppies and his mom. He’ll start to try to leave the bed area to have a wee.
He’ll start to paw, bare his teeth, growl, carry things in his mouth and play prey-killing games by 4-5 weeks old. His mom will start to prevent her puppies feeding when they want to, and he’ll learn not to bite too hard when playing with his litter mates and mom. They need clear sleeping and playing areas so they can leave the bed area to relieve themselves. This is an important start for toilet training. Puppies raised in too small a space can struggle with understanding toilet training later on.

Stage 2: 5-8 weeks old

By the age of 5-8 weeks of age weaning starts, ear and facial expressions are more obvious and it’s important your pup has great interactions with humans. You’ll see games between the litter mates, and will need toys to play with. Being raised in a breeder’s home is important as they learn about house noises and human activities. If they are exposed to kitchen noises, people coming and going, washing machines, dryers and vacuum cleaner noises, all the better!
There should be lots of contact with people of all ages, especially if they are going to a home with children, and they should be handled daily with at least 5 minutes individual attention separated from their litter mates and mom. Puppies are hugely curious at this age, although can start to become a little more cautious, and at the end of this period will come home with you.

Stage 3: 8-12 weeks old

At this stage they are highly dependent on you, need lots of social contact and really want to please you. They become increasingly cautious of new experiences and by just 16 weeks old your opportunity to train your puppy to enjoy his environment and meeting new people is all but gone, as caution overtakes curiosity. That’s why it’s more important to expose him to new experiences now, more than at any other time in his life.

Puppies playing with toys on grass


Play with him, teach him human games and to inhibit his play biting. He needs daily socialization, so get him out and about at least once a day to encounter the environments, animals, types of people and experiences he will encounter during his life.

You could consider early vaccination at 6 weeks so he has some early protection, and socializing him with other dogs you know are vaccinated are great precautions. Carry your puppy outside so they start to encounter the outside world and put him down in areas you know other dogs have not been. He’ll need lots of reassurance and positive encouragement but this commitment to great socialization gives you the best chance of having a well-adjusted dog later.

Juvenile Period 3- 6 months old

Your puppy is still highly dependent on you, eager to please with a growing awareness of his environment. Chewing behavior increases now as his teeth develop and so investing in a wide range of chews and toys so you can change them daily is a good idea to protect your shoes!
This is the time when training your puppy to have good manners is important as he grows and is able to concentrate more. You can start to fun games as a reward for a good training session. Socialization remains important so your puppy learns to cope with new situations.

Adolescence 6 months – 12 or 18 months old 

This is when puppies become independent, sexually mature and more territorial. Chewing is still a big feature of their behavior. This can be the most difficult time to get through as a pet parent, and many dogs are given up for rehoming at this time because owners haven’t laid the ground rules and done the socialization and training needed to have a well-adjusted dog. Even if you have done the hard work, you can still wonder what’s gone wrong!
You are less important to your dog as they focus on the wider world, and hormone fluctuations cause behavior changes. They can become more assertive and aggressive and any issues surface now. This can be difficult to cope with as adolescence is a selfish time and you might feel you’re losing your relationship with your pup. Don’t give up on them, keep training them, don’t let him get his own way all the time, reinforce good behavior, be consistent and this phase will pass. You could shorten training session if things get frustrating as you need to try and avoid being angry with your pup. But remember, it is just a phase!

Maturity 1 year – 18 months   

Luckily adolescence passes faster in dogs than in humans so by the time your pup is a year to 18 months old you’ll be coming out of the most difficult phase. He’ll still be inexperienced and will fill out a bit more, but your hard work will be paying off and you should have a well-mannered dog you can take anywhere. Be aware he is inexperienced so you’ll still need to watch out for hazards and top up on training but everything should be a bit more relaxed now!

Puppies with owner


The first year of any young animal’s life is intense and full of development milestones, and it will be hard work. Understanding your puppy’s needs and capabilities, and investing time in their training and development will ensure you end up with a great addition to your family!

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