The instinct of the Wolf.
There are a lot of reasons a dog will dig holes, it may be instinct.
During the winter the Wolf will eat all of the food that he kills, this is because he is unsure of the next time he will eat.
During the summer, he will dig a hole and bury part of the kill and return later to finish it off, this is a lot like your dog burying a bone in the backyard. A dog that is outside in the summer may dig a hole to get out of the heat, in the winter he may dig a hole to get out of the cold.
They may also dig because they don’t get enough exercise; it is a great way to relieve that extra energy. (Have you ever watched how much energy a dog puts out when he digs a hole?)
This is usually because the owner doesn’t realise how much energy a dog has, and doesn’t give him the amount of exercise he needs. Yelling and screaming only reinforces the activity with negative attention, any attention is better than no attention, just ask your dog.
When you give negative support, you only make the problem worse; more holes are a real problem.
If you are one of the lucky few and your dog digs in front of you, just telling him no, may solve the problem.
However, most holes are not dug in our presence, especially if the dog digs from boredom, because when you are there, he isn’t bored.
One way of stopping this habit is to put a wooden stake in the centre of the hole he has dug, tie him to the stake with his lease and leave him there for about 20 minutes.