Certain breeds like terriers have strong prey drive making tail chasing rewarding.
Instinct & Genetics
Running in circles expends energy and provides dogs solo playtime.
Exercise & Play
Lack of activity and understimulation may lead dogs to chase tails.
For some dogs, tail chasing becomes a self-soothing, compulsive behavior.
Some dogs learn tail chasing gets a reaction from owners.
Excessive tail chasing may indicate anxiety, OCD, or other psychological issues.
Anxiety or OCD
Discomfort from rear end skin or tail problems can trigger chasing.
Fleas or Pain