Developmental Stages

The canine gestation period is between 56 and 66 days with the average being around 63 days. Science has shown that even before puppies are born, they are being shaped by what their mother experiences whilst pregnant. If the mother has a less than ideal 63 days then this is likely to have a critical and long lasting effect on how the puppy develops. So while we know the environment plays a big part in the development of a puppy post-birth, it is also incredibly important pre-birth.

Much like us, puppies will also inherit genetic traits from their parents which can significantly affect the behavioural traits that a puppy displays later on in life. 

Pick your breeder wisely!


The first 12 days of a puppy’s development is termed as the neonatal period. During this phase, puppies cannot see or hear, regulate their own temperatures and are completely dependent on their mother.


The transitional period is the quickest of the developmental stages, but a lot of important changes happen to the puppies during days 13 – 21. Ears and eyes open, sensory and motor skills mature, as well as the ability to learn and play fight with littermates. Tooth eruption will begin at around 2 weeks of age with all teeth through by 8 weeks.


What happens to puppies during this period shapes what kinds of dogs they grow up to be.

This period starts at around 3 weeks of age and ends at around 12 weeks (contrary to popular advice of 12-16 weeks) and is the time when primary socialisation normally takes place. During this time it is easiest for a dog to establish relationships with humans and other species, learn about social behaviour and confidence in the environment around them. They also begin to develop problem solving abilities, physical coordination, bite inhibition and can begin to form associations. The development of a puppy during this stage will depend on the complexity of the environment around them and whether or not exposure to novel things is taking place. Besides being a time for development of social relationships, this period is also a time of extreme sensitivity and psychological stress. By 12 weeks sociability begins to decrease and puppies may become increasingly fearful of novelty. This stage therefore needs to be handled with care.

Eight weeks is said to the best time to bring a puppy home, yet 8-9 weeks has been shown to be the most sensitive period within this phase (due to the puppy’s stress hormone, cortisol, being at its peak) so this needs to be done with careful consideration and to not overwhelm the puppy. Some breeders are now opting for rehome at 10 weeks because of this. If puppies are rehomed before 7 weeks, this can likely have an effect on the puppies later in life due to missing out on important aspects of this stage.

During this period, I advise lots of play, games, problem solving activities, appropriately done handling and socialisation. This is your time to build your bond and grow your puppy’s confidence, don’t worry too much about formal training here.

“Socialisation is the learning process that a puppy must undergo in order to learn key life skills to ensure that it is happy and confident in its environment, and can communicate effectively within its social group” 

Socialisation ideally should have already been started by your puppies breeder for you to then continue. It is important that we are careful during this phase of development to introduce them gradually to things they will experience during their life. These introductions should be positive quality experiences- exposure is often not enough.

To socialise, I advise taking your puppy and exploring different places for outings (in arms if not yet vaccinated. Puppy too big to carry? Drive them somewhere and watch in the car) e.g. local parks, shops, cafes, pubs, schools, building sites etc. These can be done instead of normal walks, this way you can help them experience lots of different things without much effort. Have fun in these new places and let them watch the novelty from safe distances until they are ready to interact with things where appropriate. With things we don’t want them interacting with, we can allow them to see these things but then help them learn to ignore it or focus on us instead if this is difficult.

  • Do not drag your puppy or lure them with food into any situation, allow them to make decisions without pressure. Food lures can either risk tarnishing food (creating a negative association with it) or startle a puppy when they realise after reaching the food that they are somewhere they would rather not be. Dragging teaches puppy they have no choice and that subtle ‘id rather not’ behaviours are ignored, often leading to more obvious behaviours such as barking or growling being used to get their point across. 
  • Remember just watching from a distance is as good as getting up close and personal. 
  • Don’t teach your puppy to react to everything. While we would like to create a good association, there are some things in the environment we do not need to socialise to, we simply want them to ignore them e.g. hoover, livestock, traffic. This can be done via simply watching and not doing anything or engaging in different activities. For example, you don’t need to reward your dog every time you see a car. You could run the risk of your dog reacting (this can be simply acknowledging) every car that goes past. Simply give your puppy enough space from these initially so that they are no big deal.
    “Some things are just apart of the furniture” 
  • Protect your puppy’s confidence. Don’t put them in situations that you know will be scary for them.
Puppy socialisation is more than just puppy play. If you would however like to socialise with other dogs, remember to add a variety of ages and play styles. Lots of free for all puppy play (often found at puppy parties) will only encourage puppy play which is often rude and excessive.  If your dog is playing inappropriately, don’t wait for another dog to tell them off. Remove them from the situation and help them learn what is more appropriate. See our body language section for help on this.

Habituation to the things around them is a huge part of socialisation. Do make sure you teach your dog that some distractions we ignore. If you miss this and allow your puppy to say hello to everything they pass, this is the expectation you will be setting for your puppy which will become difficult to manage when older.

What if something bad happens? Don’t panic! Socialisation is about creating a library of really good experiences so that when puppies come into contact with a not so nice experience, it isn’t a problem. Puppies that don’t have a large library will find this more difficult than others as their experience becomes 50% good experiences and 50% bad. We want our puppies to become resilient and for that sometimes they also need to see that life isn’t always rosey. I don’t mean for one moment that you need to create bad experiences, but when they do happen, you should have enough to full back on so that your puppy can file that book, brush it off and carry on.

“Socialisation is a process, not an event”

In your weekly plans, remember to include. . . . . 
  • Animals 
  • People: sizes, builds, styles 
  • Sounds 
  • Sights 
  • Surfaces 
  • Smells
  • Handling 
  • Making choices 
  • Building relationships 
To your daily routine you can also add
  • Noises  (See DogsTrust Sounds Sociable/Scary)
  • Dress up games so your puppy can see people wearing different items
  • Garage games and sniffaris (time to explore random objects found in garages and lofts)
  • Settling in the car while stationary
  • An enriched environment so they can learn about proprioception
  • Watching the world go by from the front garden or driveway

Between 12-16 weeks puppies will go through a juvenile stage. Puppies start to become more independent, interested in their environment and able to learn much more readily. During this stage puppies will also reach a peak in teething with 42 adult teeth forming by 6-7 months. 

During this stage, I advise starting the bulk of your training. You should have already begun to reinforce your dog for appropriate choices and good behaviour and now you can begin teaching them key skills they will need to know to live in your world.


From 4 months to maturity puppies will be seen as adolescents and undergoing hormonal changes. Maturity will vary depending on the breed and size of your puppy, will smaller dogs mature much quicker than bigger dogs. Most dogs are fully mature by around 18-24 months. During this phase they should have become confident in their surroundings and formed a good bond with you, their owner. They should be learning about what behaviours are acceptable and how to interact with the world around them. This is however assuming the previous periods and stages were done right.

This stage is very much like teenagers going through puberty, brain chemistry is changing and therefore behaviour will be affected. Obedient puppies may become more selective with their hearing, do remember that while being consistent is key, this is a stage so be aware of it and try to ride it out relatively unscaved. You will need to take care to help your dog learn how to behave when aroused and not allow them to practice unwanted behaviours. Adult dogs can find dogs of this age group particularly annoying and will set even stronger expectations for them so expect a telling off or two (this should however be kept to a minimum if you’re setting them up to succeed).

Problem behaviours can arise during this stage with some dogs beginning to show a rise in reactivity to stimuli (new situations, people, dogs, objects). In the event of aggressive displays, provide space not correction. When confronted by scary things, your dog needs you to support them in order to give them time to acclimatise and build confidence. They need to feel safe with you, not in more danger than previously believed. Avoid overwhelming situations and chucking them in the deep end (if your dog is scared of dogs, classes and puppy parties are not a good idea unless overseen by an accredited trainer or behaviourist. This is an example of flooding and is likely to make aggressive displays worse as your dog fights for safety).

Appropriate socialisation and training should continue throughout this stage.

“Begin to insist on greater responsibility and awareness from the pup, and be careful to guide and help him in all situations. He has a lot of enthusiasm for life now, but he’s still lacking the skills to wisely handle the world” Suzanne Clothier.


This stage occurs from maturity which will be varied across breeds. Most dogs are considered to be socially and sexually mature by 18- 24 months (although smaller dogs will be much younger than this).