Puppy Behavior

Reaching sexual maturity or the age for sexual activity is about the same in all dogs. According to The Kennel Club of the United Kingdom, puppies usually reach puberty at six months. You may note some behavioral changes in your puppy, such as lifting his leg when he urinates. Up until six months of age, puppies of either gender will squat to urinate. However, upon reaching sexual maturity, your puppy will begin to lift his leg because he is programmed to let other dogs in the area know that he is there. The only reason for alerting other dogs to his presence is to stake a territorial claim on any bitches in the area. Other changes in his behavior may be due to hormonal changes and include running away, digging under fences and becoming more aggressive.

Hormones

The hormone responsible for sexual reproduction in dogs is testosterone. It is largely produced in the testes, though it does have other sources. These levels elevate in young male dogs, peaking around five months of age. This rise in testosterone will cause your dog to "act out" in a sexual manner. Dogs will sometimes hump and thrust a person's leg or another dog in a show of dominance, but it can also be an act of sexual simulation, according to Petplace.com.

Aging

As they age, if male dogs are not neutered, their testosterone level will continue to cause problems for them and their owners. At around seven months, male dogs can smell the pheromones put off by a bitch in heat from miles away and will travel great distances to find her. Therefore, decreased roaming is one of the benefits to having a male dog neutered.

Considerations

Besides being community-minded and pro-active in helping to solve a national problem, neutering your dog has medical and behavior advantages. There are a number of physical problems caused by the effects of free-roaming testosterone, such as testicular and perianal tumors, hernias and prostrate problems. Behavioral issues such as running away, inability to concentrate, urine marking and aggression are also dismissed by sterilization.