Why some dog breeds have naturally bobbed tails

Many dog lovers notice that some breeds come into the world with naturally bobbed or short tails, rather than the long tails more commonly seen in most dogs. This trait is not simply a matter of appearance—years of scientific research have identified a specific genetic cause behind naturally bobbed tails. Understanding this gene helps us appreciate the unique qualities of these breeds and promotes informed, responsible breeding practices.

What causes naturally bobbed tails in dogs?

The naturally bobbed tail is caused by a mutation in the T-box transcription factor T gene, which plays a crucial role during the embryonic development of dogs. Scientists first identified this mutation through studies involving breeds like the Swedish Vallhund over a decade ago. The gene affects tail formation as the puppy develops in the womb.

This mutation is inherited in an autosomal dominant manner, meaning a dog only needs one copy of the mutated gene (referred to as the "BT" allele) to express a bobbed or short tail. Dogs that have one copy of the normal gene and one copy of the mutated gene will show this natural bobtail trait. However, puppies inheriting two copies of the mutation usually do not survive embryonic development, making such cases extremely rare or nonexistent in live births.

Breeds commonly born with natural bobtails

• The Swedish Vallhund can be born with either a long tail, a short bobbed tail, or occasionally no tail due to carrying this gene mutation.
• The Pembroke Welsh Corgi is well-known for naturally having short tails or being tailless, with the bobtail gene present in the breed’s DNA.
• Australian Shepherds often exhibit naturally bobbed tails, with the gene responsible causing shorter or absent tails more commonly in the breed.
• The Brittany Spaniel includes dogs with either fully long tails or naturally bobbed tails, with the latter more prevalent in many lines.
• The Bourbonnais Pointer from France is often born with short or absent tails due to the mutation and is a popular hunting breed with a natural bobtail.
• The Australian Stumpy Tail Cattle Dog, closely related to the Australian Cattle Dog, carries the gene, resulting in their characteristic short or bobbed tail.
• Catahoula Leopard Dogs, or Catahoula Curs, rarely but sometimes carry the mutation, producing occasional tailless pups.
• The Polish Lowland Sheepdog can have a naturally short or bobbed tail, with typical tails shorter than average when tails are present.
• The Schipperke breed has about a 50% chance of being born with a short tail, carrying the bobtail gene and contributing to the variability in tail length.

Testing for the bobtail gene

Thankfully, advances in veterinary genetics have led to a reliable test that identifies whether a dog carries the bobtail gene mutation. This test helps distinguish naturally born short-tailed dogs from those whose tails might have been docked. Understanding the genetic status of your dog is vital for ethical breeding and avoiding complications.

• CLEAR: The dog has two copies of the normal gene and will have a long tail.
• ONE COPY: The dog carries one copy of the normal gene and one copy of the bobtail gene, resulting in a naturally bobbed or short tail.

It is important to note that dogs inheriting two copies of the bobtail mutation (two mutated genes) do not survive embryonic development. Responsible breeders should use genetic testing to prevent breeding two carriers, thus avoiding non-viable litters and promoting healthy puppies.

Legal and ethical considerations

In the UK, surgical tail docking is tightly regulated and only permitted under specific circumstances, often for veterinary health reasons. Naturally bobbed tails provide an ethical alternative for owners and breeders who appreciate the visual appeal of short tails without undergoing docking procedures. This genetic trait supports animal welfare and respects the puppies’ wellbeing.

Summary and responsible ownership advice

Natural bobtails in dogs arise from a specific dominant genetic mutation in the T-box transcription factor T gene that shortens the tail during embryonic development. Breeds such as the Pembroke Welsh Corgi, Australian Shepherd, and Swedish Vallhund often display this trait.

Genetic testing allows owners and breeders to verify their dog’s tail type is natural and to promote welfare-conscious breeding decisions. If you are interested in acquiring a puppy with a naturally bobbed tail, always seek out reputable breeders who prioritise health, genetics, and responsible breeding practices. Avoid supporting illegal docking and help celebrate the natural diversity in our canine companions.