Complete Guide to Short Tail Dogs: Genetics vs. Docking

While most dogs have naturally occurring long tails, there are also many known breeds that have short tails. Some of these breeds are well known, such as, the English Bulldog, Doberman, and Australian Shepherd. These breeds are often referred to as bobtail breeds.

So, you may be asking yourself “why do some dogs have short tails, if the majority of canines have long wagging tails?” That’s a totally valid question.

The short answer is that there are two reasons that a dog has a short tail: either they were born with a short tail or their tail was docked.

This guide will cover why some dogs are born with short tails and what breeds are in this group. It’s important to note that some of the dogs on this list are recognized by other major kennel clubs internationally, but not necessarily by the American Kennel Club. So some of these breeds may be new to you.

Additionally, we’ll take a look at the brief history of the practice of tail docking and exactly what’s all involved.

Dogs with short tails, especially from docking, is a very hot topic in the world of dog people. There is some major controversy and legal issues around tail docking. You might just be shocked after you learn all about it in this guide.

Check out my complete list of the 34 Natural Bobtail Breeds (with pictures) CLICK HERE!

So let’s dive right in and first talk about dogs born without tails.

Why are some dogs born without tails?

Courtesy of Wikimedia Commons

So what’s behind these naturally occurring bob tails? Well, there is a few different things at play here. There are some known and unknown genetic mutations that cause this trait in some breeds.

Let’s look at the known genetic mutation known for causing short tails.

T-gene C189G

Okay everyone, buckle your seat belt because there is some incoming nerdy science here for a second. Bear with it, it will be over soon.

According to a study published in the Journal of Heredity in 2009, titled Ancestral T-Box Mutation is Present in Many, but Not All, Short-Tailed Dog Breeds, identified that one reason for dogs being born with a short tail is the presence of the mutated T-gene C189G. There were 18 breeds identified in the study as carrying the C189G mutation.

The presence of this gene mutation causes a short tail, which can be a completely short bobtail or a mid-sized short tail. The breeds in which the study identified the C189G gene are not always born with a short tail, but there are significant odds that some puppies in those breed’s litters will be born with short tails.

Short + Short = Death

One other important piece of information that this study identified, especially for breeders, is that in these 18 breeds identified as carrying the C189G gene, two copies of this gene mutation are lethal. Meaning if both parents have short tails, some of the puppies will inherit the gene from both parents, which is lethal to the puppy. The study showed that about one in four puppies would inherit the gene from both parents and die before birth.

The 18 Natural Short Tail Dog Breeds That Carry the C189G Mutation

Australian Shepherd Jack Russell Terrier
Austrian PinscherKarelian Farm Dog
Australian Stumpy Tail Cattle DogMudi
Bourbonnais PointerPolish Lowland Sheepdog
Brazilian TerrierPyrenean Shepherd
Brittany SpanielSavoy Sheepdog (Berger de Savoie)
Croatian SheepdogSpanish Waterdog
Danish-Swedish FarmdogSwedish Vallhund
Based on information published by Marjo K. Hytönen, Anaïs Grall, Benoît Hédan, StéphaneDréano, Samuel J. Seguin, Delphine Delattre, Anne Thomas, Francis Galibert, Lars Paulin, Hannes Lohi, Kirsi Sainio, Catherine André, Ancestral T-Box Mutation Is Present in Many, but Not All, Short-Tailed Dog Breeds, Journal of Heredity, Volume 100, Issue 2, March-April 2009, Pages 236–240,

Dogs breeds introduced to the C189G mutation by cross-breeding

Believe it or not, there have been some moves to introduce the C189G mutation to breeds, mainly due to tail docking being illegal in many countries (we will get to that later). As of today, only one breed is known to have intentionally had this gene introduced.

An article written by Virginia Zurflieh, titled The Fantastic Account of Dr. Bruce Cattanach’s Bobtail Boxers, details how this was done with some Boxers. In 1992, anticipating a docking ban in Britain, Dr. Bruce Cattanach introduced the C189G mutation by crossbreeding a Boxer with a Corgi. Cattanach then backcrossed with purebred boxers. This resulted in Boxers that can be born naturally with bob tails.

The Only Dog Breed in Which the C189G Mutation Was Introduced

Info Courtesy of

Dogs without C189G mutation

The same study published in the Journal of Heredity, mentioned above, also identified six dog breeds born with short tails that DO NOT carry the C189G mutation. For these six dogs, the “genetic mechanism” for the short tail hasn’t been determined.

The 6 Natural Short Tail Dog Breeds Without C189G Mutation

Boston TerrierMiniature Schnauzer
English BulldogParson Russel Terrier
King Charles SpanielRottweiler
Based on information published by Marjo K. Hytönen, Anaïs Grall, Benoît Hédan, StéphaneDréano, Samuel J. Seguin, Delphine Delattre, Anne Thomas, Francis Galibert, Lars Paulin, Hannes Lohi, Kirsi Sainio, Catherine André, Ancestral T-Box Mutation Is Present in Many, but Not All, Short-Tailed Dog Breeds, Journal of Heredity, Volume 100, Issue 2, March-April 2009, Pages 236–240,

Untested Dog Breeds

In addition to the two groups of dogs above, there is a third group of natural short-tail breeds that have not been tested yet for the C189G mutation.

The 9 Natural Short Tail Dog Breeds Not Yet Tested for C189G Mutation

DonggyeongMiniature Fox Terrier
English ShepherdOld English Sheepdog
Entlebucher Mountain DogRat Terrier
French BulldogTenterfield Terrier
Mcnab Dog

There is still a fair bit of genetic testing to be done, but this is at least the information known so far.

Tail Docking

Courtesy of Wikimedia Commons

So, now that we know what breeds can be born with naturally short tails, let’s take a look at tail docking. If you didn’t see your favorite short tailed dog breed on the above lists, chance are their tails are docked.

Brief history of tail docking

Docking tails is kind of a strange concept and is counter to how most dogs are genetically built. Dog’s closest living ancestors, wolves, have tails. So, you can argue that the presence of a tail has lasted through every adaptation the species has went through. If a tail was a trait not needed, wolves or dogs would have naturally shed that part of their anatomy.

So, then how did tail docking become a thing?

It’s important to distinguish two main reason for tail docking. There is docking for practical reasons and there is docking for cosmetic purposes.

According to the American Veterinarian Medical Association and a fantastic article by Jill Kessler Miller , Tail Docking in Dogs: Historical Precedence and Modern Views, the origin of docking for practical and cosmetic reasons is interesting.

Practical docking

Tail docking looks to have initially occurred in ancient Rome. Tail docking, as well as, removing a portion of their tongue, was believed to help lower the risk of a dog’s getting rabies. Obviously, this seems silly today with what knowledge we have, but that was the logic at the time.

Separately, there is a long history of docking working dog’s tails. This is done to help prevent tail injuries while hunting or herding. Dog’s wagging tails could get caught on thorns or brush, causing cuts and infections. Additionally, a herding dog could possibly get a tail caught or stepped on by large livestock.

INTERESTING FACT: Companion dogs (non-working dogs) were taxed in 17th century England. Working dogs, who were designated by docked tails, were not taxed.

So, humans being humans, people figured out a way to scam the tax. Poor dog owners proceeded to crop the tails on their dogs to avoid the dog tax. Eventually, the dog tax was repealed in 1796, but the practice of docking continued.

Cosmetic docking

The docking of tails for cosmetic reasons appears to be at least a couple hundred years old. The AVMA mentions that The American Book of the Dog, 1891, mentions several times how docking improves the “pleasing appearance” of a dog – including dogs belonging to working breeds.

Additionally, in the 1950’s, pedigree standards for dog showing were established, resulting in the tail docking becoming a requirement of certain breeds.

How tail docking is preformed

Docking is preformed by removing part, or all of a dogs tail, during the first few days after birth when the puppy’s tail is still “soft”. This is usually done in one of two ways:

  1. Surgical Scissors – a veterinarian or breeder will snip the tail at the length desired.
  2. Tail Banding – a tight rubber band is placed on the tail, cutting off blood supply to the tail after the rubber band. The tail will drop off between three to five days.

Controversy surrounding tail docking

There is significant controversy surrounding the practice of tail docking. Tail docking is actually banned or restricted in all first world countries with the exception United States and Canada. Those opposed to docking believe it to be unjustified and extremely painful for puppies.

It’s unjustified

Many in the veterinary wold view docking as unjustified. Meaning that there’s typically not a good enough reason to amputate a tail. Removing an appendage simply for cosmetic reasons puts a dog at unnecessary risk. Basically, are we causing more harm by docking than what we are trying to prevent.

Additionally, there is some thoughts that docked tails may limit communication between dogs, but this is mostly anecdotal evidence and not scientific.

It’s Painful

The traditionally belief that is not painful for puppies is just not true. The common belief that puppies have lower pain sensitivity has actually been disproved in the last 20 years.

As it turns out, studies have shown puppies, and neonate humans, have heightened pain experience, not less.

This is especially controversial because docking is done without anesthesia.


So, from the information above you can see there are a few reasons for why the dogs running around you may have short tails. Genetic reasoning for the natural short tailed breeds is interesting and definitely a nice alternative to tail docking.

Tail docking can be done for practical or cosmetic reasons. For practical reasons, it can make logical sense.

A tail injury can be a dangerous injury for a dog. My Golden Retriever, Nakota, injured his tail and had to have a portion of his tail amputated due to an infection and resulting dying tissue. The injury took a very long time to heal and it was re-injured several times during recovery. I can see why working dogs would have their tails removed at birth.

Either way, the work of introducing short tail genetics to different breeds may be a safe alternative to tail docking and certainly a legal option in areas where tail docking is illegal.

Also be sure to check out my complete list of the 34 Natural Bobtail Breeds (with pictures) CLICK HERE!

Disclaimer: Docking is definitely a controversial topic. This article however, is not intended to support or object the practice of tail docking. The above content is intended to be informational.


Thank you for taking the time to read my article! I hope it was helpful and insightful. I absolutely love dogs and my mission is to help dog owners better understand their dogs and how to care for them in the best way. Please checkout my about page: CLICK HERE!

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