A wagging tail is often seen as a sign of a happy dog. But your dog’s tail is far more than a barometer of emotion: It’s a complex and highly functional extension of its spine that serves a variety of purposes.
Do Dogs Have Bones in Their Tails?
The short answer is, yes. A dog’s tail is a series of vertebrae that gets progressively smaller toward the tip. On average, a dog’s tail has between five and 20 vertebrae, which are surrounded by muscles, nerves, and blood vessels. “Dogs’ spines continue in their tails with caudal vertebrae. The number of caudal vertebrae varies between dogs,” says Jamie Whittenburg, DVM, chief of staff at Kingsgate Animal Hospital in Lubbock, Texas.
According to Bond Vets, a chain of veterinary clinics, because tails are made up of skeletal muscle and tendons/ligaments which, unlike the smooth muscle of intestines and blood vessels, it is under voluntary control. “It stands to reason that dogs have control over their tail movements just like they do over their leg movements,” says Bond Vets.
What’s the Purpose of a Dog’s Tail?
Your dog’s tail communicates a wide range of emotions and intentions to other dogs and to people. “Each dog is unique and has their own way to communicate their feelings and emotions,” says Dr. Whittenburg. “Some dogs use their tails more than others.”
And some of those uses are often misinterpreted, according to Tufts University. For example, a relaxed, friendly dog may have a tail that wags in a swishing or circular motion. However, if a dog is feeling anxious, fearful, or stressed, its tail is often lowered or tucked between its legs.
Lastly, a dog that is aroused or hyper alert may hold its tail up high and wag it in a stiff, quick motion. Rather than a sign of friendliness, it indicates a state of excitement, alertness, or aggression.
In addition to communications, a dog’s tail serves especially when the dog is running, jumping, or navigating uneven terrain. Fast, agile breeds use their tails like a rudder to shift weight and maintain stability. Think of your dog’s tail like a tightrope walker’s pole, which is used to constantly adjust their center of gravity.
What Is Dog Tail Docking?
Dog tail docking is the controversial practice of surgically removing part or all of a dog’s tail. It is typically performed on puppies that are only a few days old, often without anesthesia.
Historically, tail docking was performed on working dogs to prevent injuries that might occur while hunting or herding. It was also done for cosmetic reasons or to conform to specific breed standards set by kennel clubs.
However, the practice is now a subject of much debate. “Removing a dog’s tail can affect its communication and hinder the ability to express and convey emotions. I believe that tail docking is an unnecessary and cruel cosmetic procedure that negatively impacts dogs,” says Whittenburg.
Many veterinary organizations, including the American Veterinary Medical Association (AVMA) and the Royal Society for the Prevention of Cruelty to Animals (RSPCA), agree and oppose the procedure.
The AVMA finds the question isn’t how harmful the procedure is but whether there is justification for removing it. “The only benefit that appears to be derived from cosmetic tail docking of dogs is the owner’s impression of a pleasing appearance. In the opinion of the AVMA, this is insufficient justification for performing a surgical procedure. deeming it medically unnecessary and a cause of pain and distress for the dog.”
The AVMA and RSPCA argue that a dog’s tail is essential for its well-being and communication, and as a result, the practice is now banned or heavily restricted in many countries.
Ultimately, the practice of tail docking is considered by most of the veterinary community to be a painful and unnecessary mutilation that deprives a dog of an integral part of its anatomy, essential for communication and overall well-being.
Broken and Injured Tails
Because it’s made up of vertebrae, your dog’s tail can be broken or injured.
Dr. Whittenburg says one of the common injuries she sees is degloving, where the skin is forcibly ripped from the tail. “This happens for a variety of reasons,” she says, “including being hit by a car and having their tails accidentally shut in doors.”
And then there’s “happy tail.” This also occurs frequently and is due to the impact of an exuberantly wagging tail hitting the wall and other objects. “The end of the tail splits open and typically there is a lot of blood seen,” says Dr. Whittenburg.
While typically not emergencies, these tail injuries expose delicate nerves that cause pain, so veterinary intervention is advised.  “Sometimes, bandaging the injured area and giving antibiotics and pain medication will prevent infection, calm the nerves, and allow the tail to heal. In severe, chronic cases where the wagging will not stop and the injury will not heal, the best solution is surgical shortening of the tail,” advises the VCA Animal Hospitals.
Ultimately, a tail is a multifaceted part of your dog’s anatomy. It’s an indispensable tool for balance and communication, and a vital component of its overall well-being. Understanding the function of the tail—beyond just a wag—lets you better interpret your dog’s emotions, appreciate their unique physical abilities, and advocate for their health.
