Dog owners recognise scratching and circling as two common behaviours that dogs practice when they're about to lay down. While these habits may seem silly or even compulsive, they're rooted in the behaviour of wolves and wild dogs. Scratching, in particular, also serves several important purposes for domestic dogs.
Dogs are notorious for urine marking, but that's not the only way they spread their scent around. Like wolves, they also have glands in the pads of their feet that release a unique odour. This happens naturally when they walk or run, but they can strengthen the scent by scratching. When a dog scratches the place where it's about to bed down, it's marking that spot with its scent.
Like people, dogs often prefer a soft bed rather than a hard surface. Outside, a dog may scratch as a way of creating a bed out of grass and leaves. Dogs that sleep on bedding inside often use their paws to rearrange blankets and pillows to their liking. They may exhibit this same behaviour on hardwood floors or carpets even when there are no objects to move or arrange.
Rearranging a sleep surface--whether it's sand, grass or cotton--may help dogs regulate their temperature. On a hot day, a dog left outside often will dig beneath the surface layer of dirt to scoop out a cool oasis. If the dog is cold, rearranging blankets or pillows may help spread warmth.
Scratching is wired into the canine DNA. Wolves, believed to be the ancestors of all domestic dog breeds, scratch their bed area before they lay down for many of the same reasons as pet dogs.
Some dogs may scratch the floor or bed before they lay down simply because their nails are too long. This is probably the easiest type of scratching to prevent because the solution is to trim the nails.
Sometimes a dog's scratching becomes destructive to carpets, floors or bedding. If this happens, many experts suggest giving the dog its own bed, if it doesn't already have one. If it does, add a few blankets or items of old clothing.