Interpreting Tail Wags in Dogs

By Ryan Llera, BSc, DVM; Lynn Buzhardt, DVM

What does a wagging tail mean?

When your dog wags his tail, is he telling you that he’s happy? Not necessarily! Canines know many variations of the “tail wag” and they all mean different things. In fact, a wag of the tail is one of the best methods of communication in the canine kingdom.

Like human infants, dogs must learn their language. Pups aren’t born knowing what a wagging tail means any more than a newborn baby understands words. But when a pup is about a month old, he recognizes the need to communicate with his mother and siblings, so he picks up the lingo. The pup wags his tail to tell his littermates that he’s tired of playing or to tell his mother that he’s hungry.

Why do dogs wag their tails to communicate?

Words are the basis of human communication, so people are good listeners. Dogs, on the other hand, are watchers. Lacking a verbal vocabulary, dogs communicate broader messages with body language by taking a certain stance, moving their ears, furrowing their brow, shifting their eyes or wagging their tails.

Tail wagging works well for dogs. Since canine vision is attuned more to movement than to colors or details, dogs readily discern different tail wags. Evolution has also helped by producing tails that are more visible. Some tails have color variations such as dark or light tips, some are lighter on the underside, and some are really bushy. All of these traits accentuate the tail wag and enhance communication.

What messages does a wagging tail communicate?

Before we learn to speak “tail,” we must recognize that the neutral or natural position of a dog’s tail varies by breed. Most dogs have tails that hang down near their heels when they are relaxed. But some dogs, like Beagles, hold their tails more vertically. Others, like Greyhounds and Whippets, curl their tails under their bellies. Still others, like Pugs and Boston Terriers, have tails that coil tightly against the body and don’t wag at all.

Tail position may indicate:

  •  Preparedness or agitation. When dogs are alert, they stand with their ears up and tails raised. This posture indicates that they   are watching and ready to confront whatever caught their attention.
  •  Negotiation. When a dog suddenly stops wagging his tail and freezes, it may mean that he wants divert a threat without being   aggressive. Many dogs do this when petted by strangers, to communicate that they don’t want to interact with them.
  •  Aggression. When a tail moves from a neutral position to a vertical one or arches over the back, it indicates that the dog may   be aggressive. The higher the tail, the greater the threat. This high tail position also releases more of the dog’s scent from the   anal glands, announcing the aggressive dog’s arrival and marking his territory.
  •  Submission. When a tail moves from the neutral position to a lower one, the dog is submissive and is not a threat. 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 lower tail   position reduces the amount of scent emitted from the anal glands and allows the dog to remain in the background or fly under   the radar.
  •  Curiosity. When a dog is curious about something, she holds her tails straight out in a horizontal position.
  •  Happiness. When a dog is happy, he holds his tail in a neutral or slightly raised position and adds a healthy wag.

The rate at which a tail moves adds further meaning to canine communication.

Wagging speed may indicate:

  •  Excitement. The faster the wag, the more excited the dog. A tail wag may range from very slow to extremely rapid (known as   flagging). Sometimes the dog’s tail wags so fast that it appears to vibrate.
  •  Insecurity.  A dog that is tentative about meeting a new person or another dog may wag his tail ever so slightly to indicate that   he is insecure.
  •   Friendliness. A dog that is very friendly may wag his tail more freely and even wiggle his hips at the same time.
  •   Aggression. When a dog wags his tail very fast while holding it vertically, he may be an active threat. Remember that a person    can get bitten by a dog that is wagging its tail!

Canine “tail talk” is so complex that even the direction of the wagging is significant. Studies show that dogs wag their tails to the right when they are happy or confident and to the left when they are frightened. Interestingly, there is a scientific reason for this.

The left side of the brain controls movement on the right side of the body and vice versa. Therefore, the left brain is engaged when the tail wags to the right and the right brain causes the tail to move to the left. Since the left side of the brain is associated with positive feelings like love and serenity, a happy dog wags his tail to the right. Conversely, the right half of the brain is associated with negative feelings like fear and depression, so a frightened dog wags his tail to the left.

Can tailless dogs communicate?

Dogs without tails communicate, but they have limitations. They may 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.

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