Natural bobtail

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 his Kennel Club for permission to cross Corgis into his lines and then backcross to Boxers, introducing the gene into his lines. 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.

Animals with a natural bobtail

Cats

More than one gene is responsible for tail suppression in cats; research is incomplete, but it is known that the Japanese Bobtail and related breeds have a different mutation from that found in the Manx and its derivatives.

American Bobtail

Japanese Bobtail–tails are short and kinked, but not entirely absent

Karelian Bobtail–tails are short and kinked, but not entirely absent

Korean Bobtail–tails are short and kinked, but not entirely absent

Kurilian Bobtail

Manx, and Cymric or Manx Longhair; tails range from full to entirely absent

Mekong Bobtail, a variant of the Siamese

Pixie-bob

Experimental breeds (mostly cross-breeds of the above):

Alpine Lynx cat

American Lynx cat

Desert Lynx cat

Highlander cat

Owyhee Bob

Dogs

A mutation in a gene called the T-box transcription factor T gene (C189G) accounts for natural bobtails in 21 dog breeds, but not in another 5 breeds, for which the genetic mechanism is yet to be determined. This study counted Rottweilers as not having the C189G gene, but tested only five Rottweilers, only two of which were short-tailed dogs.