Because they are revuelcan in bones?
It is thought that the dogs have this attitude to mask their scent, is a behavior that has been of its ancestros, the wolves, these make it to desimular their own scent so that the prey that are arranged to hunt not eave me of their presence, this way they can approach in furtive form their victim and hunt it with more facility.
Some specialists in behavior animal maintain that it is a conduct who make for ?warning? that they have found other dogs.
She does not concern the reason, unfortunately, some of our domestic friends have conserved this one inherited ancestral habit of his ancestors.