Intelligence

Dogs who were bred for jobs that require decision making, intelligence, and concentration, such as herding livestock, need to exercise their brains, just as dogs who were bred to run all day need to exercise their bodies. If they don't get the mental stimulation they need, they'll make their own work -- usually with projects you won't like, such as digging and chewing. Obedience training and interactive dog toys are good ways to give a dog a brain workout, as are dog sports and careers, such as agility and search and rescue.

See Dogs That Have Low Intelligence