Your pup’s developmental stages and why you should care about them

We need to understand the developmental stages our puppies go through as we need to provide the right training, support, exposure, and socialization at each stage. Things that happen during each stage can have a profound impact on a dog’s long-term behavior, in particular, fear, aggression, and resilience. Having a well-rounded adult dog is something we all want and recognizing their fear periods and how this can impact their emotional well-being and development in the long run. Did you know that your puppy’s socialisation should start before they even come home to you?

Neonatal Period (0–2 Weeks)

During the neonatal stage, puppies are entirely dependent on their mother. Their eyes and ears are closed, and they spend most of their time sleeping and nursing. At this age, there’s very little environmental interaction or learning beyond the comfort and safety of their litter [1].

Transitional Period (+/- 2 to 3 Weeks)

This is a short but crucial phase in development. The puppies start to develop their senses. Their eyes and ears open, and they begin to explore their immediate surroundings. This is when their motor skills develop, and they become more active. While fear isn’t yet a significant factor at this stage, early positive and gentle handling can set the groundwork for future interactions and socialisation[1].

Socialisation Period (+/- 3 -16 Weeks)

The socialisation period is one of the most critical phases in a puppy’s life. During this time, they are highly receptive to forming social bonds and learning about their environment. Positive exposure to various people, animals, sounds, and experiences is extremely important to shaping a well-rounded adult dog. Socialisation during this period has a lasting impact on their behaviour, making it a key time for introducing puppies to the world in a controlled, and positive way[1].

Fear Periods in the Socialisation Stage:

Around the 8–12 week mark, puppies experience their first significant fear period. This is when they become particularly sensitive to new experiences and can easily form fear-based responses. During this window, it’s important to ensure that any exposure to new environments or stimuli is positive and non-threatening. Negative experiences at this stage can lead to long-term fear or aggression issues. This sensitivity is linked to the puppy’s rapidly developing nervous system, which makes them more reactive to stimuli [1].

Juvenile Period (+- 3–6 Months)

The juvenile period which is also known as the ‘terrible teens’ is influenced by increased independence. Puppies become more curious and eager to explore their surroundings. Their motor skills are more refined, and they start to solidify the behaviours and social cues they’ve been learning. However, they are still developing emotionally and mentally, so ongoing socialisation and positive reinforcement are incredibly important [2].

At this stage, some puppies may experience a second fear period, usually around the 4–6-month mark. This is typically a shorter phase but can still lead to heightened sensitivity and reactivity, particularly to unfamiliar people, animals, or environments. Like the earlier fear period, it’s important to carefully manage their experiences during this time to prevent the formation of long-term fear-based responses [2].

Adolescence (+/- 6–18 Months)

Adolescence can be the most challenging stage for both puppies and their owners. As their bodies and minds continue to develop, many adolescent pup’s become more independent, test boundaries in the sense of figuring out what behaviours work or don’t and may even seem to “forget” cue’s you may have taught them. It’s so important to remember and understand that the environment plays a HUGE part in their behaviour.

During this period, various areas of the brain mature at different rates. This phase is associated with increased levels of stress hormones, such as cortisol, which can influence a dog's emotional responses and sensitivity to stimuli. The amygdala, a region in the brain linked to processing emotions, becomes more reactive, contributing to heightened fear responses. Additionally, changes in neurotransmitter levels, particularly serotonin, impact mood regulation and influence how the dog perceives and copes with stressors. These neurochemical fluctuations shape the dog's behaviour and emotional responses during this critical developmental period [4].

The two last fear stages are around 6–13 months, and around 14-18 months, where adolescent pups might suddenly become cautious or reactive towards things they were previously comfortable with. This stage can coincide with hormonal changes, and careful environmental management is needed to set the dog up for success, not put them in a position where they may ‘fail’, and to reinforce positive experiences as well as avoid letting fearful responses become habitual. It’s a good time to revisit training, focus on building confidence, and continue appropriate exposure and socialisation.

Swift at an agility show as a pup

The Role of Fear Periods in the Fight-or-Flight Response

This is the most important thing to understand when it comes to fear periods!!!! Instincts are involuntary and are a natural part of puppy development, designed to help them become more aware of potential threats to defend and protect themselves. These periods are characterised by the fight-or-flight response, which is triggered by specific chemicals, mainly adrenaline and cortisol [3].

Adrenaline is responsible for the immediate fight-or-flight response, making animals more reactive and alert to perceived threats. Whether they choose to flee or defend themselves depends on their temperament, past experiences, and how they are managed during these fear periods.

Cortisol, the stress hormone, plays a key role in managing longer-term stress. Repeated exposure to stressful situations without proper appropriate management can result in chronic anxiety and reactivity in the dog[4].

How Do You Support Your Puppy Through Fear Periods??

Fear periods can be daunting for both puppies and their owners, but with the right support with a force-free positive reinforcement trainer, puppies can navigate these stages and become more confident and resilient with emotional maturity and time.

To end off my very long post here are a few tips to help manage fear periods…

Reward behaviours you like when you see your puppy doing them. This includes calm behaviour and DO NOT punish fearful responses, which could make the situation worse. Puppies do not misbehave the way humans interpret it! Their behaviours are usually natural responses to their environment, and what we might label as “misbehaviour” is often just a result of unmet needs, confusion, or stress.

Introduce new experiences gradually, ensuring that your puppy doesn’t become overwhelmed. Make new interactions positive and manageable.

Remember that fear periods are temporary. Remain calm, and don’t force your puppy into situations they find intimidating.

I hope this helps you understand fear periods and your puppy or adult dog better. Please reach out to your nearest force-free, science-based trainer in your area if you need help.

References:

[1] Scott, J.P. and Fuller, J.L. (1965) Genetics and the Social Behavior of the Dog. Chicago: University of Chicago Press.

[2] Serpell, J. (2017) ‘The Domestic Dog: Its Evolution, Behavior, and Interactions with People’, in Serpell, J. (ed.) The Domestic Dog: Its Evolution, Behavior and Interactions with People. 2nd edn. Cambridge: Cambridge University Press, pp. 21-47.

[3] Overall, K.L. (2013) Manual of Clinical Behavioral Medicine for Dogs and Cats. St. Louis: Elsevier Health Sciences.

[4] Freedman, D.G., King, J.A. and Elliot, O. (1961) ‘Critical Period in the Social Development of Dogs’, Science, 133(3457), pp. 1016-1017.