Pembroke Welsh Corgis don’t have tails because about 1000 years ago, Corgis were used as cattle herders. Because the farmer did not want the Corgi injured while doing his or her job, the farmer (or breeder) docked (took off) the Corgi’s tail at birth.
In the present time, it has become a custom to dock a PWC’s tail, even if the corgi is no longer used for herding. It has also become a requirement in the breed standard for the PWC to have his or her tail docked in order to compete in a dog show.
A common method in docking the tail is called rubber-band docking. The rubber band is tied around the puppies’ tail and the tail is said to shrivel and fall off within three to five days. It has become less common to dock a Corgi’s tail because more often a Corgi is born without one.