Bred to fearlessly herd cattle, the blue heeler needs a strong leader in its pack or it will assume the role of pack leadership. Unchecked, this tendency can develop into dominance and even aggressive behavior toward both other dogs and humans. The heeler's high intelligence make it easy for the experienced dog owner to train away unwanted behavior.
Heelers are fiercely loyal to their owners and will position themselves between a new person on the scene and their owner. They are suspicious by nature and, unless trained otherwise, may growl or attempt to herd the interloper away by nipping at their heels. When trained, they make excellent watch dogs that will bravely protect you in a dangerous situation.
With Other Animals
The need for a strong leader will sometimes trigger the blue heeler to dominate other dogs in your home that have a more passive nature. This can manifest as growling, biting or herding the submissive dog into a corner. A heeler may also appear aggressive during normal play with other dogs, using the same amount of assertive energy he would use in herding cattle.