Did you ever step out of your door at night only to find that you felt you were exploring the moon due to the craters and mountains that rose magically in your absence? Do you own a dog? There just may be a connection here.
Dogs dig for many reasons. Mainly it is to entertain themselves and explore their surroundings. This is especially true if you dog is left in the yard alone for long periods. Being deprived of human contact will leave him to his own devices for entertainment.
Puppies and young dogs will do it to release the energy they have if no other outlets are provided.
Terriers were meant to dig. They are bred to dig and do so very effectively. Busy dogs, happy dogs, bored dogs or dogs that see you gardening and think it may be a fun thing to do are all possibilities.
The pattern we are noting here is the fact that they do not have enough human interaction and are left to their own devices. This can be improved or completely reversed. Any training of a dog takes persistence and consistency on your part.
Sometimes dogs dig holes to find a cool spot in the summer or a warmer place in winter that may provide shelter from the wind. This behavior can be helped by providing a dog house for your dog and plenty of fresh water. Check the water frequently in winter if you are in a cold area to prevent freezing. Hot weather may require occasional handfuls of ice to keep the water cool.
Provide a designated digging area for your dog. This area can be covered with loose dirt or sand. A child's sandbox may be an alternative for smaller breeds. If you catch your dog in the act, a verbal command such as 'no dig' may work if immediately led to an acceptable area. Rocks or chicken wire may deter your dog from digging in unacceptable parts of your yard. Burying a Kong type toy filled with peanut butter or other treat will also give them something to do.
Toys can be buried in the area you choose to keep them busy. He can "discover" his treasures and feel very proud.
Human interaction is vitally important. Perhaps you can teach your dog a few simple tricks. Work on these for a few minutes every day. Taking him to obedience class or some other type of doggie learning class will also help. Practice just the things they are taught until your next session.
Toys your dog loves may be enough to leave lying around in the yard to keep him entertained. Walking your dog twice a day is a good way to teach him socialization and give him a chance to be with you. It also is a great training device. You can teach him commands such as heel, sit, stop, come or others during these walks.
Don't punish a dog after the fact. They would think that you are punishing them for what they are doing at that particular moment. Enjoy him and be as good a friend to your dog as your dog wants to be to you.
References
Handbook of Behavior Problems of the Dog and Cat, 2nd Edition, By Gary Landsberg, BSc, DVM, Dipl ACVB, Doncaster Animal Clinic, Thornhill, Ontario, Canada; Wayne Hunthausen, BA, DVM, Animal Behaviour Consultations, Westwood, Kansas, USA; and Lowell Ackerman, DVM, PhD, Dipl ACVD, MBA, MPA, Westborough, MA, USA
November 4, 2009, "Dig This: How to Get Your Dog to Stop Digging," The Humane Society of the United States