Are There Terriers Born Without Tails?

The rat terrier is the single type in the AKC group whose breed standard mentions a naturally bobbed tail. The lack of a bobtail on a rat terrier won't get him disqualified from show, though. Length is unimportant to the standards, which state that the tail can be naturally bobbed, docked or left naturally long.

You might wonder why some rat terriers are born with short tails while others have a full-length tail that falls down to their hocks. The answer is all in the genes. Puppies get two "tail" genes -- one from mom and one from dad. If a puppy gets at least one short-tail gene, he'll have a short tail. If he gets both long-tail genes, he'll have a normal-length tail. The problem comes when a pup gets two short-tail genes. In his book "The Genetic Connection: A Guide to Health Problems in Purebred Dogs," Lowell Ackerman explains that puppies who get two short-tail genes don't typically survive to be born. Those who do are born with spinal abnormalities and other birth defects.

Tail docking for dogs who are born with long tails is typically a cosmetic procedure that is unnecessary for most dogs in modern times. Docking the tails of dogs has its origins in England some 200 years ago. Specific dog breeds -- including terriers -- were classified as working breeds and exempt from taxation. These breeds were distinguished by their shorter, docked tails, a characteristic which made performing their duties easier, such as hunting in brush or below ground where a full-length tail could get in the way or be injured.

Rat terriers aren't the only breed who carry a bobtail gene. Entlebucher mountain dogs, Brittany spaniels, Pembroke Welsh corgis, old English sheepdogs, boxers and Australian shepherds are all naturally short-tailed. Docking takes place in many cases when puppies of these breeds are born with long tails, particularly if the puppies are to be show dogs.