Events during your puppy’s developmental stages can shape the way he behaves as an adult. Whether he grows up to be your best friend or haunted by behavioral problems can depend on how you handle your puppy during his developmental stages. Much of his behavioral, cognitive and emotional makeup will be established before adulthood. Understanding your puppy’s developmental stages can free you to raise your new best friend to be a healthy, happy adult. The following time periods approximate the normal stages.

Neonatal (days 1 to 12)

During this period your puppy’s eyesight and hearing are not well developed. He will stay close to his mother and litter mates. Some studies show that mildly stressing your puppy during this period will enable him to better handle stress as an adult. In addition, mild physical stress can increase the size of the brain.

Transitional (days 13 to 20)

In the transitional stage of your puppy’s development his eyesight and hearing have improved and he will begin to walk. Although he will still be most greatly influenced by his mother and litter mates, this period is an ideal time to introduce your puppy to various stimuli such as bones, toys and even friendly cats.

Socialization (weeks 3 to 6)

This is the most important of your puppy’s developmental stages for socialization with other dogs. He will learn dog activities like biting, barking and body posture. His mother will also teach him discipline and he will learn to relate to other dogs by establishing a pack hierarchy created through play.

Human Socialization (weeks 7 to 12)

At this point your puppy has the same brain waves as a fully developed adult, allowing for the most rapid learning he will ever experience. The way your puppy interacts with humans will depend on this stage of his life. This is also the near the end of the time when you can easily introduce him to and make him comfortable with new people and places.

Fear Imprint (weeks 8 to 11)

As the name suggests, in this period any trauma your puppy experiences can create fears. These will have a more lasting effect and may become generalized fears later in life. Be especially positive and gentle during this period.

Ranking (weeks 10 to 16)

Social dominance is tested in the ranking period by learning to compete and cope. This is your puppy’s developmental stage that requires the most leadership, control and structure. He will be more likely to challenge your authority during this stage.

Flight Instinct (weeks 16 to 32)

Your puppy will seem to have forgotten anything he has learned, such as to play fetch or come when he is called. Be ready with chew toys to help with the need to chew, because his adult teeth will be growing in. Obedience schools get most of their calls during this time.

Second Fear Imprint (months 6 to 14)

A heightened level of aggression is common for puppies during this period. Your puppy may become shy, timid and apprehensive of new things. His fears should be treated with patience during this stage, which usually occurs during growth spurts.

Adulthood (years 1 to 4)

Now your puppy has grown into an adult. Any behavioral or socialization problems will become evident during this stage. However, if you have successfully navigated your puppy’s developmental stages he should be a loyal companion and best friend.