Physically, he is entering adolescence. It may be a period of awkwardness and rebellion; Male puppies start to lift their leg and take an interest in identifying the sex of other animals by sniffing, and may become overly aggressive as an outlet for the developing sex drive. Females come in heat for the first time, after which a decision as to spaying should be made.

A puppy does a lot of shedding now, as his baby coat falls out and his adult coat takes over. If his ears drooped during the teething period, they will probably become erect again. Six months is minimum recommended age for giving a puppy his first annual rabies vaccination, and may be mandatory in some states.

Psychologically, he has gained so much self confidence that he has begun to get ideas of his own and sometimes thinks his ideas are better than yours. You will need to be quite firm at times in order to maintain your authority. This is vital with larger breeds, which may be ready for obedience training. He has already become attached to his old habits, but is still very quick to form new ones.

He tries to understand everything you say and even attempts to communicate with you, telling you that he would like to go out, that he is hungry, or bored. His sense of property and territory is well-developed, and he has learned to respect other's territory too. His intuition is developing, he recognizes friends before they have rung the bell, and is at the door to greet you whenever you come home.

What he needs most is kind, firm handling, nourishing food, lots of exercise and activity to keep him out of trouble and lots of affection and love to make up for all the scolding you have to do.