An overview of canine development

Behaviour is influenced by genes which are inherited.  

Dogs don’t inherit ‘behaviour’, they inherit genes which contain proteins, in turn containing information which ‘codes’ for specific behaviours.  

Genotype is a term used to refer to the genetic material inherited through generations. 

Phenotype is a term used to describe an individual’s observable characteristics which include physical form/appearance, anatomical, physiological, and developmental processes, and behaviour. 

In terms of appearance, phenotypic genetic codes express physical characteristics, such as eye colour, coat type, and ear type, depending on specifically which genes a dog inherits from their parents.

However, genes which influence behaviour are not necessarily automatically activated when a puppy is born, and whether they are expressed or not might depend on the puppy’s environment and life experiences.

For example, a puppy might have genes which code for ‘stalking’ behaviour, but if they don’t experience any kind of situation in which stalking behaviour is triggered, then they might never display this behaviour.

As genes are inherited, the breeding of carefully chosen parents can play a role in specifically selecting desired physical, health, and potentially behavioural characteristics.

However, whether these are expressed or not will depend on various other external factors. 

Behaviour can be influenced by the experiences of a dog’s mother during pregnancy.  

If poor, the mother’s physical health during pregnancy can negatively impact puppy development, for example, if she hasn’t received adequate nutrition.

Additionally, physical (for example, illness) and/or emotional (for example, anxiety or fear) stress experienced by the mother during pregnancy can increase cortisol levels which might cross through the placenta to negatively impact puppy development within the uterus. 

Behaviour can be learned. 

Behaviour doesn’t just happen by itself. It is a reaction that is triggered by a stimulus – either internal or external – which then results in an outcome or consequence, although this may or may not be consciously experienced by the individual.

Behaviour can be strengthened (made more likely to happen again) or weakened (made less likely to happen again) depending on the outcome for the individual. For example, if behaving in a particular way works out well for a dog, they’ll be more likely to behave in that way again.

Dogs learn through and during every experience and encounter they have and will adapt their behaviour in future accordingly, so rather than being ‘set in stone’ from birth, behaviour remains flexible throughout a dog’s life.  

Evolutionary theory suggests that, at base level, the biological aim of any species is to survive long enough to successfully replicate its genetic material. Adaptive behaviour enables an individual or species to respond to: 

• changes in their environment  
• changes in their motivational states (hunger/thirst/reproductive urges)  
• changes in their pathological states (illness/pain).  

All of which enable them to take whatever action is necessary to aid survival. 

Different species have evolved specific behaviour to help them thrive in this way. Dogs developed as a group-living species with successful co-operative strategies, hence much of canine communication is comprised of mediation and affiliation.

Puppies aren’t born behaving like adult dogs, so how does their behaviour develop over time? 

In 1963, when the scientific field of behavioural science was emerging, Dutch biologist Nikolaas Tinbergen published an article posing four questions about behaviour observed in animals: 

1. What purpose does the behaviour serve for the animal in terms of aiding survival?  

When a dog exhibits behaviours such as dropping to the ground and rolling over onto their back, holding their ears back, trembling and tucking their tail beneath their body when they encounter an unfamiliar dog, they are likely communicating that they do not wish to interact at that moment and pose no threat. 

The purpose of this behaviour is to maintain individual safety by avoiding any interaction that could cause harm.  

2. How has the behaviour evolved over time? 

Regarding natural selection, ‘survival-enhancing behaviours’ would do just that, thus allowing those individuals more opportunities to mate and reproduce, passing down any related genes to their offspring.

These behaviours would then be more likely to be expressed in successive generations – as long as they continued to be beneficial. 

Regarding artificial selection, over the years humans have purposefully bred individual dogs with desirable characteristics to reproduce in successive generations, for example, behaviours such as excellent hunting, herding, and guarding abilities – all of which were useful for human survival. 

3. What specific set of circumstances trigger the behaviour?  

These can include physiological stimuli such as hormones and pheromones, for example, oestrogen and progesterone are linked to nesting and food-acquisition behaviours. 

These can also include environmental stimuli including the sensory information a dog receives; for example, an unexpected sight, sound or even smell might trigger escape behaviour such as bolting, depending on how the dog perceives and feels about it. 

4. How does the behaviour develop – and how is it influenced by experience and learning throughout the individual’s lifetime?  

Because behaviour happens in response to physiological changes, an individual’s behaviour will likely be influenced at different points in a dog’s life when physical changes are also occurring; for example, during growth stages, adolescence, and when a dog becomes elderly (see below for more detail). 

Behaviours that are repeated become honed and ingrained over time. The outcome of a specific behaviour will dictate whether or not it a dog decides to repeat it in the future. Essentially, dogs learn to do what works out well for them and to avoid doing things that don’t.

For example, a dog may learn exactly which behaviours work to keep themselves feeling safe in a specific environment, which is why wriggling, growling, and snapping can gradually become default actions in the veterinary clinic.  

These four questions highlight how behaviour is constantly developing throughout life. It is not static and is affected by both intrinsic and extrinsic factors. These factors can emerge at certain periods in a dog’s life, as discussed in detail below. 

Prenatal period

Recent studies demonstrate trans-placental maternal influence, in particular finding that litters from mothers who experienced stressful handling during pregnancy display higher behavioural reactivity.  

Neonatal period (birth to approx. 14 days)  

During this period, puppies are sensitive to tactile stimuli and certain tastes/smells, but their motor abilities are limited and their eyes and ears are neither open nor functioning; their only need is to be able to locate their mother’s teat in order to suckle.

Despite this neurosensory immaturity, puppies can learn simple associations (within the limits of their own sensory and behavioural capacities) and will make vocal responses to hunger or cold.  

Episodes of stress during this period can have significant long-term effects on behavioural and physical development, the outcomes of which appear to depend on the intensity of the stress experienced.

Research has shown that puppies exposed to ‘mild’ stressors from birth to 5 weeks were more confident, exploratory, and social when tested again later in novel situations.

Puppies handled gently on a daily basis from 3–21 days after birth were calmer, more exploratory and gave fewer distress calls than littermates who were not handled at all.

This research suggests that the mild stress associated with early handling produces an adaptive change in the nervous system, which enables the individual to cope better with mildly stressful situations in adulthood.

These findings can be used to guide those rearing puppies to introduce gentle handling at an early age to achieve positive outcomes.  

However, positive adaptation is dependent on the handler being able to discriminate between mild, moderate, and intensely stressful experiences.

Evidence suggests it’s worth gently handling such young puppies, but in a very measured, considerate way and always observing and recording responses.

Further research, for example, Generation Pup (see below) will help to explain the impact of intense stress related to traumatic experiences as a risk for negative physical and emotional health in later life.  

Transitional period (opening of the eyes at approx. 13+/-3 days to the opening of the ear canals at approx. 18–20 days)  

During this period, neonatal patterns of behaviour are replaced with those more typical of puppyhood and adult life, for example, puppies are now interested in solid food, display an observable startle response to auditory stimuli, are able to crawl backwards as well as forwards and are beginning to stand and walk.  

Anogenital stimulation by the mother is no longer required to stimulate toileting, which starts to be performed outside of the sleeping area.  

The litter begins to perform social play accompanied by growling and tail-wagging.  

Socialisation period (approx. 3 weeks to 12 weeks)  

Puppies are weaned naturally by their mother during this period, and there is rapid development in coordination and cognitive abilities.  

The socialisation period enables puppies to form positive relationships with animals or humans encountered within a familiar social context.

For example, puppies readily form reliable social bonds with humans as long as they have had some positive human exposure before 7–8 weeks. This socialisation ‘window’ seems to remain open for up to 12–14 weeks for some individuals. 

Puppies who are 3–5 weeks old can also learn to recognise novel objects (for example toys and bedding) and will exhibit less fear when meeting these objects again at 7–8 weeks than puppies meeting these items for the first time.  

It is beneficial to introduce novel stimuli and facilitate positive human and animal interactions during this socialisation period to ensure that puppies are equipped with the confidence to deal with new things – as well as being comfortable with both human and animal interactions during their adult lives.  

Juvenile/pre-adolescence period (approx. 12 weeks to the onset of sexual maturity, the timing of which will vary according to type/breed)  

It is important to understand that the age at which a dog reaches sexual maturity will vary between individuals. Some small/miniature breeds may be sexually mature at 6–7 months, while some larger breeds may not reach this stage until they are 18–24 months.  

Pubertal/adolescence period (onset of sexual maturity)   

Puberty in the dog is considered to occur bet 6-9m in most males, and 6-16m in females. However, behavioural/social maturity may not be reached until much later, until somewhere between 12 and 24 months, and might differ depending on breed.

Sexual maturation can also be breed-dependent with smaller breeds becoming sexually mature frequently earlier than large/giant breeds. 

During adolescence, dogs will experience maturation of different parts of the brain at different rates, which, coupled with a rise in amounts of reproductive hormones produced, might trigger greater exploratory behaviour (often reported by owners as their dog paying them much less attention, especially when outside).   

As a dog reaches about 6 months of age, their owner may be less tolerant of ‘typical puppy behaviour’ and expect them to behave more like an adult dog; while other dogs might begin viewing them as competitors for resources, such as available food, valued items, human-attention, or access to potential mates. 

Dogs are also learning all of the time, so the way a dog behaves during their adolescence will likely have been influenced by the quality and quantity of learning they have experienced throughout their life so far.  

This adolescence period is probably the most poorly studied in relation to the experiential effect on adult behaviour. 

Social maturity into adulthood 

During this development stage, which incorporates puberty and adolescence and continues until a dog becomes geriatric, a dog’s ability to cope with any situation they encounter is often expected and easily taken for granted.  

It is important to remember that dogs are always learning, through both positive and negative consequences of their behaviour.

Unless owners are aware of this and consciously take steps to guide their dogs into behaving as desired, they might inadvertently place their dogs in situations in which they learn to repeat undesirable behaviour. (As discussed in handling of dogs during consultations, including examination, use of clinical equipment and medical procedures). 

Geriatric stage (approx. 7 years onwards)  

This stage of life is often overlooked and yet during this period a dog’s behaviour can change in many ways, for many reasons.

This could be in response to deterioration in health, sensory acuity and mobility, as well as loss of established learned responses within various social and environmental contexts.

For example, an elderly dog might feel increasingly vulnerable should their ability to avoid any unpleasant activity be affected by poor health or age-related anatomical changes. This might render them less tolerant and quicker to communicate growing discomfort about any situation.

Cognitive decline and dysfunction must also be considered in older dogs with associated behavioural affects. 

It is worth noting that the way individuals behave during each life stage is likely to depend on a multitude of factors, including the extent of the influence of early life events as well as their emotional experience of current events.

These events could include visiting the vet, diet/nutrition, exercise amount and type, sleep amount and quality, types of social interactions experienced, and environments encountered, as well as their physical health.

The importance of these factors in relation to health and behaviour is currently being explored by the longitudinal study Generation Pup. 

The importance of further research relating to the health and behaviour of dogs

Dogs Trust funds and operates Generation Pup, a unique research project aiming to follow 10,000 dogs throughout their lives. 

These dogs can be any breed or crossbreed and owners must live in the UK or the Republic of Ireland. Information is collected about each dog in relation to their environment, household, health, and behaviour.

Researchers will then investigate the extent that these factors are important in the development of a range of health and behaviour conditions which impact canine welfare.

The results of the Generation Pup study may suggest preventative measures that can be put in place to safeguard wellbeing or lead to new approaches for therapy or treatment for dogs.  

By December 2021, more than 5,000 puppies had been recruited to the project and recruitment is ongoing. For more information, please see the website www.generationpup.ac.uk and encourage puppy owners to join the project.

Puppies must be under 16 weeks when joining the project (or 21 weeks if coming through quarantine).