Every dog owner has observed how dogs, especially males, carry out several powerful movements of digging in the ground after completing their act of defecation.
It moves very little away from the exact place where the feces have been deposited and then, with strong backward movements of the front legs, and in particular, the hind legs scratches the ground repeatedly before moving away.
Sometimes this digging behavior occurs after urinating. But it is less frequent.
The original explanation given for this action is that it is reminiscent of the time when the wild ancestors of dogs used to cover their feces just like cats do.
Domestication is believed to have eroded the efficiency of action, with today merely a useless vestige of the once hygienic procedure surviving. However, this is not true as recent observations of wolves in their natural state have revealed that they too carry out the same kind of digging actions.
Therefore, there has been no “decline” due to domestication. Another suggestion has been that the dogs simply tried to spread their feces, expanding the area where they left their scent.
Some species of animals are dedicated to spreading their droppings; for example, the hippopotamus, which has a specially flattened tail that moves back and forth, in a fan-like fashion, to spread its strong stools far and wide. However, although dogs always scratch with their paws very close to their feces, they avoid touching them.
This leaves us with two possible explanations. First of all, it has been observed that, in the wild, when wolves scratch the ground they remove it and the soil spreads over an area of one to two meters, which leaves a clear visual mark along with the odorous signal.
Dogs that scratch on the sidewalk or other hard urban surfaces, where today so many owners take them out for a walk, leave a very little visual impact with their scratching; but this is simply bad luck for them.
In a more natural soil, its legs would leave quite considerable visible marks. Second, it has been argued that the only efficient sweat glands in a dog’s body are those between its toes, and what the animal does is nothing more than add this personal odor to that of feces.
This idea may not seem convincing to us, because although our human noses can detect dog feces quite easily, our response to the smell of doggy feet does not exist.
In the scent-rich world of dogs, however, this additional form of scent markings may well add fascination to the canine obsession with taking a walk.
There is a very good chance that both the odor factor and the visual factor play an important role when the dog digs in a natural environment.