6. The German Shepherd
This is a large breed dog that is one of the smartest dog breeds ever. The German Shepherd is a breed that serves in the U.S. active duty in the police force as well as in the military. The primary task, or job, is to smell out many different scents and smells to help assist police and military staff. This breed has the best nose around and can find even the smallest smells with no problem. In addition to making a great workforce breed, the German Shepherd is a common household pet that can serve as a protector and as a friend. They are large dogs and typically are pretty active and energetic.