Dogs eating "non food" items is called:
The consumption of nonfood items is a disorder called PICA. Although pica can be a sign that a dog’s diet is lacking in some nutrient, when pica occurs in puppies and young dogs the most common culprit is boredom. Occasionally, eating nonfood items develops into compulsive behavior, resulting in a dog who’s highly motivated to find and consume specific objects. Rock eating is the most common form of pica, but dogs compulsively consume a variety of inedible objects, including plastic bags and containers, human clothing and wooden objects.
When your dog runs in circles trying to catch his tail this can mean one of three things
Dogs can tilt their head for several reasons
Walks In Circles Before Laying Down
Why do dogs walk in circles before laying down?