A natural bobtail is an animal's tail which due to a mutated gene grows unusually short or is missing completely. The genes for the shortened tail may be dominant or recessive.
Because of legislation restricting or preventing docking, natural bobtails are growing in popularity among the dog fancy for some traditionally docked breeds. For example, one Boxer breeder and geneticist in England has successfully petitioned the Kennel Club for permission to cross Corgis into his lines and then backcross to Boxers, introducing the gene into his lines.[1] This would have been unheard of in decades past. A number of these bobtail Boxers have been exported to various countries around the world.
However in some breeds, such as the Rottweiler, natural bobtails are not universally accepted in the Country of Origin Breed Standard.