One of the more frequent causes for destructive behavior in dogs is separation anxiety, a condition in which the dog is terrified of being left alone. In addition, specific elements in the dog's environment can trigger fears and phobias, in these cases, chewing, digging and scratching can be tension- or fear-relieving behaviors.
Playful destruction and investigative behaviors are common in young dogs, dogs new to a household, active dogs and dogs that have few opportunities to engage in physical activities. When a dog becomes bored he may resort to behavior that is destructive in order to obtain the stimulation that he needs. This can be a particular problem among large breed dogs as well as young dogs that do not receive sufficient play time, exercise and activity.
Yet another contributing factor to destructive behavior can be frustration with being closed in, often referred to as barrier frustration. If the dog becomes tired of feeling closed in or if he notices something on the other side of a barrier that is attractive to him then he may attempt to destroy the barrier in order to either break free or reach whatever it is that he desires.