Herding dog breeds often chase tails trying to "herd" them since the motion triggers their nipping instincts.
Herding Instincts
Certain breeds like Bull Terriers are genetically prone to tail chasing tendencies. The reasons behind it are not fully understood.
Genetics
Dogs will chase tails excessively due to obsessive compulsive disorder. It can indicate anxiety.
Anxiety & Stress
Chase circles provide mental & physical stimulation for under-exercised dogs with excess energy to burn
Boredom Buster
In some cases, pain or nerve dysfunction makes tails irritated targets. Vet exams help rule out causes.
Medical Causes
Some dogs learn tail chasing garners attention, even if negative, from shocked owners.
Attention-Seeking
Simple reasons like fun, enjoyment and having a tail readily handy provide dogs endless entertainment.
For Fun!