|MadSci Network: Zoology|
Dear John: Domesticated dogs are interesting in that their behavior sometimes reflects the behavior of their wild counterparts. These behaviors appear to be ingrained and may have no purpose in our house pets. An example is the circling behavior that some dogs display before they lay down. In the wild, this action serves to flatten the grass before the dog rests. The best this may do for our domesticated friends is to flatten the carpet. My best guess for the reason for the shaking behavior would be to again relate it to the wild canines. Shaking would probably be helpful in eliminating fleas and other parasites that accumulate on the dog while it is resting. The typical dog shake begins at the head and works its way down the body ending at the tail. If your dogs are constantly shaking their head, it could indicate a medical problem. Ear infections and sometimes bad teeth can cause head shaking. Take your dog to see its veterinarian.
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