Physically, he may stop growing taller if he is of a small or medium-sized breed. His lanky body will start to fill out and his coat to achieve its adult color and texture. His appetite is large, and it is vital to his future health to give him a generous, balanced diet. His sexual characteristics become more pronounced, males looking more masculine and females more feminine.

Psychologically, the sexual differences are more apparent too. Males tend to bark more, to play rougher and more aggressive games. They become more competitive and enjoy racing with other dogs, and sometimes bully smaller ones. Females generally make it clear whether they are going to be quiet, affectionate home-lovers, or tomboy sporting companions.

Atavistic instincts such as hunting, running, digging, and tracking begin to seek expression. Puppies who are settled enough to concentrate may begin training in their working or sporting specialties. Those who are still too immature can be given a basis for future training by playing games designed to exercise their native aptitudes, all curious, explorative, eager to learn and proud of each new accomplishment.

What he needs most is mental and physical activity, greater responsibility and independence in areas where he can be trusted, new experiences beyond his home territory, firm but kindly discipline, lavish praise for his achievements and good behavior, lots of companionship, and more specific training for his adult life.