The term watchdog is often confused with guard dog. The role of a guard dog is protection. Guard dog breeds such as Rottweilers, Doberman pinschers, bull mastiffs and German shepherds offer strength, courage and the ability to incapacitate an intruder. Watchdogs, on the other hand, serve as alarms. They're attentive, good listeners and not shy about barking. They alert you to strangers or events but do not offer physical protection.
While many breeds may fall into the watchdog category, some breeds are better watchdogs than others. And there are always exceptions within a breed. A dog typically known for alertness and watchdog qualities may turn out to be a couch potato, unconcerned when strangers approach. Recommended watchdog breeds include terriers, poodles, miniature pinschers, Shih Tzus, dachshunds and Chihuahuas.