When we think of dogs’ tails we probably think of one thing: wags. The wagging tail is one of the most famous forms of non-verbal communication in the animal kingdom. But tails are so much more than wags. And wags mean so much more than you might expect. Dogs do not wag their tails when they’re alone; the tail comes alive when they see us and other dogs.
The tail is actually an extension of the dog’s backbone. It has muscles and bones that work together to create movement and can include as many as 23 vertebrae. Soft discs cushion the spaces between the vertebrae and so allow flexibility. This complex tail structure can easily be injured when rubbed against tree bark, wire fencing, concrete blocks or damaged while fighting etc. It has always been my belief that tail injuries in forests, many years ago, were the original reason for tail docking, long before it became fashionable for some dog breeds to have their tails docked.
Dogs mainly use their tails for Balance, Communication and Pheromone distribution.
When a dog runs at full speed chasing prey he uses his tail to be able to turn quickly without falling over. In order to do that he throws the front part of his body in the direction in which he is heading. His back bends but his hind quarters will continue to go in the direction in which he was heading. This could slow him down or even make him fall. By throwing his tail in the same direction that his body is aiming, it serves as a counter weight which reduces the tendency to spin off course.
Dogs also use their tails for balance when walking on narrow surfaces much like a tightrope walker uses his balance bar. When swimming, the tail is used as a rudder to help the dog move and turn.
For most breeds of dog the tail serves as a sort of signal flag that communicates information about the animal’s emotional state.
How tail wagging starts
Pups are not born knowing what a wagging tail means any more than a newborn baby understands words. They do not wag their tails until they are roughly about 30 days old. Until this time, puppies mostly eat, sleep and crowd around each other and their mother to be nursed. They are able to wag their tails, but don’t at this stage.
By the age of six or seven weeks, puppies begin to socially interact with each other in the form described by psychologists as ‘play behavior.’ It is through playing, that puppies learn about their own abilities and that if they bite a littermate, they are likely to get bitten back. Puppies now start to learn ‘dog language.’ They learn to use signals to indicate their intentions and also how to avoid conflict. This is how tail wagging behaviour begins. The pup wags his tail to tell his littermates that he’s tired of playing, or to tell his mother that he’s hungry. Later when he joins the human pack he will also wag his tail when begging for food.
Why do they use their tails to communicate?
Humans use words to communicate, and as a result people are good listeners. Dogs on the other hand are good observers and use their bodies to communicate with each other. They are born with a body language that they can use to “speak” to each other. It is the way they stand, move their ears, furrow their brow, bare their teeth, shift their eyes or wag their tails that “talks” to other dogs and to us.
Tail wagging works well for dogs because canine vision is more attuned to movement than to colours or details. Dogs easily recognise different tail wags. Some are more visible because of the tail size and variations of dark or light tips, some tails are lighter on the underside and some tails are really bushy. These features all help to make a dog’s tail communication much easier to recognise.
Dogs’ tails vary by breed. Most dogs have tails that hang down near their heels when they are relaxed. Some dogs like Beagles, hold their tails more vertically. Others like Greyhounds and Whippets curl their tails under their bellies. Pugs and Boston Terriers, have tails that coil tightly against the body and don’t wag at all.
Interpreting tail movement
Knowing the meaning of how a dog is carrying and using his tail can go a long way to showing you how your dog is feeling and what he is saying to other dogs.
Natural position Tails do not wag and hang down near their hocks or heels.
Happiness When a dog is happy, he holds his tail in a neutral position or slightly raised and adds a healthy wag.
Confidence When the tail high is held high and curls over the back of the dog it indicates confidence and self assuredness.
Alertness When dogs are alert or curious about something, they stand with their ears up and tails are straight out. This position indicates that they are watching and are ready to confront whatever caught their attention.
Negotiation When a dog suddenly stops wagging his tail and freezes, it usually means that he wants to divert a threat without being aggressive. We see that often when two dogs meet. Many dogs also do this when petted by strangers, to communicate that they do not want to interact with them.
Submission When a tail moves from the neutral position to a lower one, the dog is submissive and not a treat. If the tail is tucked tightly between the rear legs, the dog is scared. He perceives a threat and is asking not to be harmed. This allows the dog to remain in the background and be left alone.
Aggression The dog stands tall and moves his weight onto his front legs. His tail straightens and is raised somewhat above his back. It indicates that he may be aggressive.
Tail wagging is an indication of a dog’s excitement. The more vigorous the tail wags the greater the excitement.
Canine “tail talk” is so complex that even the direction of the wagging is significant. Studies* show that when dogs wag their tails to the right they are happy or confident, but to the left they are likely to be unsure or frightened.
In 2007,* researchers discovered that the way a dog wags its tail also gives clues about what it is feeling.
Specifically, a tail wagging to the right indicates positive emotions and a tail wagging to the left indicates negative emotions.
A 2013 study* found that dogs understand the asymmetric tail wagging of other dogs; a right-wagging tail relaxes other canines, while a left-wagging tail makes them stressed.
Research on the approach-avoidance behaviour of animals has shown that the left hemisphere is associated with positive-approach feelings, and the right hemisphere is associated with negative-avoidance feelings.
Can tailless dogs communicate?
Dogs without tails generally approach other dogs or people cautiously to avoid miscommunication. They depend on other aspects of body language such as ear position, facial expression and stance to communicate their intentions.
Pheromone distributionAnother form of communication is spreading the dog’s unique scent around. There are two anal glands or sacs located under the tail. These contain each dog’s special scent, which is as unique as fingerprints are to people. When dogs wag their tails, muscles contract and press on these glands, causing a release of some of their scent. A dominant dog with a high wagging tail will release more ‘information’ than a dog that holds his tail lower. The dominant dog wagging his tail widely is saying, “I’m here” while the frightened dog with his tail between his legs, covers his anal glands and does not want to draw unwanted attention to himself.
*Originally published on Live Science.