Perhaps second only to “Why did the chicken cross the road?" is the question of why dogs chase their tails. Most of us have seen a canine companion circle around and around in a usually futile attempt to catch its tail. Why do those silly dogs do that?
Chasing one's tail — also called whirling — is a natural behavior often seen among different species of predators. Some experts believe that tail chasing is simply a form of play that young predators engage in when they have free time. Unlike prey animals, predators don't constantly worry about being eaten by other animals, so they have time to play.
Anyone who has ever played with a puppy knows that they often chase their tails. This is perfectly normal when they're young and playful. Some puppies act as if they're not aware that their tails are attached to their bodies! When they become bored — which happens frequently with young puppies — chasing that wagging end back there can seem like quite the cure for boredom!
We often wonder what puppies would do if they caught their tails. One snap of the teeth is probably enough to teach most puppies that their tails are indeed attached to their bodies.
Whether they learn that their tails are always going to be following them around or they just don't play as much anymore, older dogs tend not to chase their tails like puppies do. When older dogs chase their tails, it can be a sign that a trip to the veterinarian might be a good idea. For example, older dogs might chase their tails if they have fleas or worms.
Tail chasing in older dogs can also be a sign of a behavioral problem. Like humans, dogs can develop compulsive disorders. Sometimes these disorders cause dogs to chew or lick themselves. In other cases, they can cause them to chase their tails for no apparent reason.
Sometimes older dogs might chase their tails for no particular reason other than that they've been confined too long indoors. Certain breeds, such as terriers and German shepherds, also tend to chase their tails more than other breeds.
If you notice an older dog chasing its tail often, it's a good idea to take it to a veterinarian for a check-up. The veterinarian may be able to diagnose a problem that can be fixed with medicine. A veterinarian may also be able to give you some ideas for how to deal with tail chasing if it becomes a problem.