How Long are Dogs Considered Puppies?

by Pauline Gill
    Small breeds tend to mature faster than larger breeds.

    Small breeds tend to mature faster than larger breeds.

    Apple Tree House/Lifesize/Getty Images

    Reaching maturation for a dog is dependent upon the breed and sex of the dog. There are different types of maturation -- behavioral, sexual and physical. Each type has its own indicators. Puppies mature into adults as early as 6 months and as old as 3 years.

    Behavioral Maturation

    Maturation is an ongoing process that doesn't occur over night. For most dogs, this period is between 1 and 3 years of age. For some dogs, it may be 4 years of age. It is during this time of behavior maturation, your pup will rise in aggressive behavior. He may become protective and territorial. He may challenge your dominance. One test that he has reached full maturity is when you can leave him alone in the house and he doesn't damage your property.

    Sexual Maturation

    Maturation can also be identified with sexual behavior. For the male dog, it is when he starts to lift his leg to urinate and finds interest in a female dog. For the female, it's when she goes into heat. Male dogs become fertile when they are around 6 months of age and reach full sexual maturity by 12 to 15 months of age, according to the American Kennel Club. Females go into heat after 6 months of age and as late as 18 to 24 months of age.

    Physical Maturation

    Physical maturation is another indicator that your dog is heading towards adulthood. The skeleton frame and tissue growth may still be developing when a dog reaches sexual maturity. Small-breed dogs, under 20 pounds, reach their full height between 9 and 12 months of age. Medium-breed dogs, ranging from 20 and 50 pounds, reach full height between 12 and 14 months of age. Large- and giant-breed dogs reach full height between 12 and 24 months of age.


    The amount of socialization, the environment, the breed of dog and the sex of your dog all play an important role in your puppy's development. As a dog matures into an adult, he will be fun, energetic and playful. He will need lots of exercise, socialization and mental stimulation. Maintaining your dominance is imperative. Teaching your dog verbal commands and how to walk on a leash will help him understand your position as pack leader.

    Photo Credits

    • Apple Tree House/Lifesize/Getty Images

    About the Author

    Pauline Gill is a retired teacher with more than 25 years of experience teaching English to high school students. She holds a bachelor's degree in language arts and a Master of Education degree. Gill is also an award-winning fiction author.

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