Why do dogs dig holes?

Dogs seem to be very good-natured animals, but beware of the wild side! DNA examinations have discovered that dogs belong to a wolf sub-species called Canis Lupus familiaris. And it seems that since the species first appeared these animals have excavated looking for something or maybe just for the fun of it, until it was genetically settled as part of them. This means modern canines will also do it by nature. Now then, try to remember how kids act when they're bored and try to call one's attention, well it is thought that dogs dig for the same reason kids have

Just for you to know, races with skills to excavate that flourished in the United Kingdom were meant for and very much appreciated in hunting activities; up to the point that they started to call them "ground dogs." Surely, if we see them digging in our courtyards we'll call them by some other names rather than "ground dogs."