Both nature and nurture play a profound role in providing the essential foundations for puppy development, but did you know that a huge amount of their development has already happened before you even bring them home! This means that choosing an ethical and well informed breeder is essential so don’t be afraid to ask questions and do your research. Simply knowing that your puppies parents are registered with the Kennel Club doesn’t mean that your breeder has reached any particular standard. Selecting for good temperament in both the parents is essential and should always trump selecting for physical characteristics so it’s always asking for a bit of detail on parent temperaments and previous litters. Equally the quality of the mum’s prenatal experience as well as her ability to care for her litter will all contribute to your puppy’s future temperament, so do ask.


Puppies are born with unlearned, innate mechanisms which develop according to the particular puppy’s genetics.   These genes have an indirect impact on behaviour by their regulating of the biological processes which influence behaviour e.g. the availability and regulation of certain neurotransmitters resulting in certain dogs which may be more or less emotionally reactive, inhibited or excitable.  Artificial selection has been used to create the border collie’s heightened sensitivity to sound.   Genetics can also influence puppy development directly through in-breeding and heritable medical conditions.  Breeding primarily for appearance and conformation will destabilise the predictability of behaviour and it is the appearance which is a primary factor in breed shows and clubs.  British Bulldog’s were the most commonly mentioned breed in the “Independent Inquiry into Dog Breeding”, Patrick Bateson, in the category of dog’s selected for extreme physical traits resulting in excessive welfare issues for the adult dog from physical difficulties in the upper respiratory tract to skin infections and birthing difficulties, and no doubt also leading to less stable temperaments due to the excessive focus on physicality.  In addition, the fact that 86% of British Bulldog’s are born by caesarean section has a knock on impact on the welfare of the pups during the first few weeks of life.  Breeding for good health, temperament and behaviour should remain paramount.  Good genetics are an essential foundation for puppy development, providing for good physical health and the best opportunities to develop into an adult dog free from behavioural concerns.    Without good genetics the dogs behaviour as an adult is more likely to be impacted by the behavioural consequences of living with poor health and may show less stable temperament prone to stress and reactivity.

Prenatal Health

Prenatal health and the corresponding health and welfare of the dam are also important. Heightened stress during pregnancy can disrupt the proper development of the puppies’ stress response as well as giving rise to a poorer birth outcome and lower birthweight puppies (which are in turn more likely to die young.  Lazinski et al point out in ‘Effects of maternal prenatal stress of offspring development’ (2008) there may be sensitive periods during gestation as has been shown with other mammals during which maternal stress is important, with likely early to mid-stage gestational stress leading to poor birth outcomes.   Enthusiastic amateur breeders are likely to miss this stage altogether and commercially bred dams are unlikely to be receiving the care that they need at this stage.  Puppies born from a stressful pregnancy are more likely to have ill-health as adults and the consequent behavioural consequences of living with illness and to have poorly regulated stress responses.

Maternal care

Quality and quantity of maternal care also directly impacts on the temperament of adult dogs.  “Levels of maternal care in dogs affect adult offspring temperament” (Foyer et all 2016) showed that the total number of Mother Pup Interactions in the first three weeks influenced the adult behaviour of the puppies at 18 months in terms of physical and social engagement as well as aggression.  Thus, smaller litters may be advantageous to the puppies who receive a greater quantity of interactions.  Guardini et al in “Influence of Maternal Care on Behavioural Development of Domestic Dogs Living in a Home Environment” found that increased maternal care, both in terms of quantity and quality, in the first three weeks was positively correlated to a puppy engaging with an unknown human at 2 months old, indicating more secure attachment.

During the neonatal stage (from birth to 12 days) separation from the litter for just 2hours can lead to sensitivity to stressful situations later in life.  In contrast, daily gentle handling and exposure to varied stimulation from this early stage through to five weeks, has been shown to aid development result in calmer puppies.

Therefore, smaller litter sizes and protection from separation from the dam should result in pups developing into adult dogs less likely to show behavioural problems.  Avoiding birth by caesarean section would seem to be an important factor, where recovering from the anaesthetic alone may take 2 to 6 hours after which the dam may be in pain and therefore less likely to show natural behaviour.  Certain breeds e.g. British and French Bulldogs are routinely born this way may be behaviourally disadvantaged right from the start.

Socialisation starts early!

Primary Socialisation stage starts when the puppies’ eyes and ears are both working and the puppy is able to move around, this is typically from 3 – 5 weeks and is the time that most rapid learning takes place.  Play and exploration is essential for puppies’ development at this time and lots of experience of novelty from meeting new people to walking on new textures and hearing new sounds.  Puppies removed from their mother during this stage will have lasting behavioural problems.  Puppies bred for commercial purposes are considerably less likely to have this experience.  In addition, special care needs to be given to litters of just one or two puppies.

Maternal influences on the puppy continue during this phase, mothers who demonstrate reactivity and anxiety are more likely to pass on these traits at this time.  Ideally, only well balanced dams would be used for breeding as they will model more adaptive behaviours.

Secondary Socialisation stage 6 – 12 weeks is a sensitive period and plenty of positive, incremental exposure through active socialisation to people of all ages, new environments, dogs of various breeds, size and age as well as body handling and novel foods must take place.  Many puppies born during the first covid19 lockdown will likely struggle through much of their adult lives due to the lack of this broad positive socialisation.  Puppies need to feel comfortable in a wide range of situations and not overwhelmed and socialisation checklists are a great tool for new puppy owners.  Unmanaged access to all dogs in public is not the goal as this can lead to the puppy becoming overwhelmed or scared, especially since not all adult dogs have the patience to meet a new puppy.  Care with vaccination schedules is also important, it is all too common for breeders to give one set of vaccinations for puppy owners to be told by their vets that they need to ‘start again’, delaying the puppy’s socialisation sometimes with devastating consequences.

Independent Inquiry into Dog Breeding, Patrick Bateson 2010

Effects of maternal prenatal stress on offspring development: a commentary, 2008, Lazinski, Shea & Steiner

Levels of maternal care in dogs affect adult offspring temperament, 2016, Foyer, Willsson & Jensen

Influence of Maternal Care on Behavioural Development of Domestic Dogs (Canis Familiaris) Living in a Home Environment, 2017, Guardini, Bowen, Mariti, Fatjo, Sighieri and Gazzano