Adolescence can appear in smaller dogs as early as 5 months. In larger breeds, it can start as late as 9 or 10 months. In giant breeds, adolescence doesn’t take place until 12 to 18 months.
In general, the larger the dog, the longer it will take to physically mature. Some breeds can remain adolescents until they are two and a half, or three years old.
Adolescence is expressed in male dogs by scent marking behavior. Scent marking behavior is stimulated by the release of testosterone into the dog’s system. At this time, males may become macho. Male dogs may become less friendly and even somewhat aggressive to other male dogs. He may begin lifting his leg in the house. He may become very interested in girls, tend to roam, and certainly not interested in listening to you! Some males at this age become totally unruly.
In females, adolescence is marked by the onset of the heat cycle, estrus. During this three week period, your dog could become pregnant. So, keep her away from all male dogs. Female dogs exhibit erratic behavior during estrus. Some get real moody and insecure. Others become quite bold or even aggressive.
Spaying/neutering your dog will help to alleviate these problems!
Adolescence is a very difficult time for pet owners. They are surprised when their cute little puppy becomes a free and independent thinker. Adolescence is certainly a good time to start (or reinstitute) rigorous training. You must work hard NOW to mold the dog of your dreams. Establish yourself as the leader of the pack. Be realistic about your expectations. You cannot expect young dogs to grow up overnight. Learn to appreciate your dog’s adolescence for it is a truly wonderful time. At this time of their lives, dogs are very energetic and exuberant in their responses. They can be full of beans, but still, delightful playmates. You as the owner must learn to channel that energy and exuberance into learning, working, exercising, and playing games. It is not too late to to train (or retrain) your dog to help him to become a long–lasting companion.