The phases of puppy growth start at the neonatal stage at a puppy's first two weeks, then continues to the transitional period, the socialization period, the ranking period and finally, the adolescent period. Each part of a puppy's development lasts a few weeks until adolescence, which occurs anywhere between six and 18 months.
During the neonatal period, puppies are able to touch and taste but do little else. It is during this time they are more influenced by their mother and littermates and begin learning social skills. Two to four weeks later, during the transitional period, their eyes begin to open, and they begin to learn how to walk. Their sense of smell and hearing begins to mature, and they may also learn how to bark at this period.
The next four to 12 weeks is considered the socialization period. This is the most important time to take your puppy out and introduce her to other people and dogs. Around the seven week mark in this period, housetraining may begin. The ranking period lasts for the next three to six months and is when the puppy learns dominance and submission. Teething issues are most common around this time as well. Finally, after six to 18 months, a puppy enters adolescence. The puppy now recognizes that she is part of a pack and may begin exploring her dominance during this period.