An curved arrow pointing right. A dog chasing its tail may be a sign of a direr issue. Like humans, dogs can suffer from a form of obsessive-compulsive disorder, called canine compulsive disorder.

These may include panting, pacing, or whining in addition to the tail-chasing. Dogs can show many signs of mental illnesses, like obsessive-compulsive behaviors such as tail-chasing and tail-chewing.