EMOTIONAL, PHYSICAL, AND MENTAL DEVELOPMENT OF PUPPIES
Puppies–who doesn’t love the sweet breath and attitude of a wiggly, adorable pup? But, puppies grow up
quick. And to keep them sweet and willing, owners must understand a little bit about the growth and development of
The following is a general discussion of critical periods in a dog’s emotional, mental, and physical
development. If a critical learning period is missed, although a dog may be trained, its basic and natural reactions are
permanently affected and its full potential will never be reached. Missing one or all of these periods may cause a
puppy to become emotionally and mentally handicapped in its social interactions with other animals and humans–for
Puppies cannot be taught anything prior to 21 days. They need only to be kept clean, warm, dry, (between 80
and 90 degrees) and allowed to nurse and sleep. These needs are usually met by the dam (mother dog.)
On average, puppies open their eyes somewhere between 11 to 19 days, with 13 days being average.
Puppies cannot hear anything before three weeks of age. Puppies begin to walk unsteadily on the 18
early as 12 days. From 21 to 49 days, playing and play fighting begins.
At approximately three weeks of age, puppies begin to go toward sights, sounds, or smells, and their
tendency to “whine” decreases. All their sense organs are now functional. The puppy is no longer dependent on reflex
responses to hunger, cold, and touch. It can see, hear, smell, taste, and feel. They can eliminate independently and
will normally leave their nesting and play area to eliminate. Their memory develops. By three weeks of age, their
brains start to take on adult characteristics. By seven weeks, they have “adult” brains and “mature” brain waves are
At this three week stage, great changes take place mentally and physically to puppies. They find sudden and
unexpected stimulation emotionally startling. Any additional noise, confusion, or rough handling can cause puppies to
become “fear imprinted.” Puppies should not be subjected to excessive stimulation during this period, as they are
having to cope with several newly developed senses at once. What a puppy learns during its third week becomes
fixed and will influence its attitudes toward man, other animals, and its environment, throughout its life.
A critical socialization period begins at three weeks, and lasts to four months of age. A puppy’s basic
character is set during this time. Puppies need to interact with humans and other animals in a variety of places
and situations and need individual attention during this period.
Puppies should not be weaned or adopted before seven weeks of age. Weaning before the seventh week
may cause noisy or nervous behavior for life. Puppies need their litter mates until seven weeks to learn to interact well
with other dogs. Taken before seven weeks, puppies miss critical socialization periods, and may show less interest in
normal dog activities for life.
Puppies adopted after seven weeks may pick fights with other dogs as adults. However, neither adopting a
puppy before seven weeks or after eight weeks will have such a drastic or negative effect that you should never
consider adopting a puppy outside of seven weeks. There are simply too many other factors to be considered when
choosing a puppy for this to be the deciding factor.
At seven weeks, puppies’ brains are fully developed. This is the best time to adopt a puppy. It has had an
opportunity to interact adequately with both its mother and litter mates and time to learn the socialization skills critical
to its future interaction with humans and other animals. If weaning and transfer occur simultaneously, the best time to
adopt is at eight weeks.
Research shows aggression develops in puppies that do not stay with their mother long enough and also in
puppies that remain too long. Puppies taken at the end of the fourth week and given a lot of human attention may
become so socialized to humans they do not care for other dogs. Some identify with humans so strongly that they
express sexual desires toward humans rather than dogs, such dogs can be difficult or impossible to breed.
Positive training and gentle discipline can start at eight weeks. With proper training, puppies can be expected
to obey every command they have been taught. While housebreaking can begin at 8 weeks, do not expect immediate
success. Generally speaking, up to 8 months, a puppy can be expected to “hold” eliminations for one hour per month
of age. In other words, a three month old puppy should only be expected to wait three hours MAXIMUM time between
From 8 to 12 weeks also marks the beginning of another fear imprinting period.
From 12 to 16 weeks, puppies cut teeth and declare their independence. The puppies decide who the “pack
leader” is going to be. It is critical to establish yourself as leader during this period. Nothing helps a puppy learn
appropriate dog behavior towards humans more than simply taking it away from its litter mates and having a pleasant
session of one on one play, training, or work daily.
Although these important critical learning periods occur, one should never interpret this to mean that a dog
cannot be trained after these periods. Dogs can be trained throughout their lives and, if the training is done properly,
dogs enjoy the process. Dogs that have no defined purpose are often bored and boredom can lead to behavior
problems. Training is an important way for your dog to express its energy, intelligence, and instincts.