Up until a few years ago, a puppy under 6 months of age was not supposed to have any set behavior pattern. He was more or less expected to learn a few rules (such as using his newspapers or going outside) and gradually develop his sociability, reaching his peak when about a year old. He was not of school age. A young pup's life was spent in playing, eating and just physically growing up.

The story is different today. We now know the learning and socialization process begins very early in the pup's life. Young puppies are ready to learn and adapt to their environment when they are from 19 to 20 days old. There are five critical stages in a puppy's life. And all of these stages occur before a pup is 4 months old.

The Five Critical Stages in A Puppy's Life

Stage one: The first stage is from birth to about 13 days. At birth, the puppy is practically helpless. He's blind, deaf, toothless and is restricted in motion (he can crawl or slither on his stomach, with his paws making swimming motions). He experiences very little in the way of learning. He's strictly a creature of reflexes. His total behavior pattern is built around reflexes dealing with food, elimination and bodily contact with his mother and litter mates.

Stage two: This stage extends from the 13th day to the 19th. It begins on the 13th day when the puppy opens his eyes (13 days is an average; some pups open their eyes earlier, some later). For the next 7 days, the puppy moves very quickly through sensory, motor and psychological changes. At the end of the 7 days, the pup can see, hear and walk. His milk teeth appear and he can eat solid food.

Stage three: The third stage begins on the 19th or 20th day after birth and continues until the puppy is 7 to 10 weeks old. It is a crucial stage in the puppy's development, one that sets the pattern for future behavior. And it is the stage when socialization begins and the pup forms a relationship with human beings and other animals.

The third stage is ushered in by the pup's startled reaction to sounds. In stages one and two, the young puppies ignore sounds. But the puppy in stage three will really jump if you make a loud noise. He will also show an investigative curiosity about people and animals, and will tussle and scrap playfully with his litter mates. During this stage, the puppy's nervous system is still immature.

In general, what happens to a pup during the third stage of his life will determine his future behavior.

Stage four: Stage four begins when the puppy is from 7 to 10 weeks of age. This is the usual age at which puppies are weaned from their mothers. The pup is not completely independent, but he now has some increased motor skills and his nervous system is similar to that of an adult dog.

The 7- to 10-week age group is ideal for raising a puppy. It is the best age at which to establish a sound relationship between dogs and people. If the puppy has had a happy third stage, he's eager to form an attachment. And what's more, he's ready to learn.

Stage five: The fifth and final critical stage starts at about 12 weeks of age and lasts until the pup is 4 months old. Now the puppy starts to assert himself. He'll be bold, perky; testing you in all kinds of situations. It is time to teach him discipline.

An understanding of your dog's instincts and behavior is a must for intelligent dog ownership. It's true that dogs just grew up in the "old days". But don't compare the "old days" with today. Know your dog and know him well. He's an extraordinary animal!