" A team of veterinarians has found a surprising link between compulsive tail-chasing in dogs and high cholesterol, according to a study published in the March issue of the Journal of Small Animal Practice.
The finding adds to a growing body of evidence -- mostly from studies on humans -- that high cholesterol may be a marker for behavioral problems such as panic attacks and obsessive compulsive disorder, which could be expressed by frequent tail-chasing falls in dogs."
http://dsc.discovery.com/news/2009/03/24/dog-tail-chasing.html