Watchdog barking is triggered by visual or auditory stimulation—passersby, slamming car doors, a cat on the lawn. Watchdog barkers were sentries in a previous life.
Boredom barking happens when a dog is left alone often and doesn’t get enough exercise or mental stimulation. It’s the equivalent of a human being in solitary confinement banging his head against the wall.
Demand barking occurs in dogs that have learned that barking gets them what they want, like balls thrown, doors opened, dinner, or attention.
Barrier frustration barking typically comes with posturing such as snarling or baring of teeth. The three most common occurrences are: dogs left in a backyard too long, dogs in cars, or dogs on leash who would be perfectly comfortable with whatever they’re barking at (most often other dogs) if they were off leash.
Separation anxiety barking is characterized by incessant home-alone barking coupled with for example house soiling, visible anxiety upon departure and arrival, and destruction around doors and windows.
To cut down on any kind of barking, start with giving your dog plenty of exercise. Second, arrange for mental stimulation when he’s left alone. Feed him using puzzle toys or stuffed KONGs. Consider hiring a dog walker or, if your dog is social, sending him to a doggie daycare when you’re away at work. As for demand barking, immediately stop rewarding the behavior: Ignore your dog or walk away when he barks. Then pick times when he isn’t barking, tell him ‘nice quiet,’ and pet or treat him. In all cases, a trainer can help—and if you suspect separation anxiety, calling one is crucial.