Think wagging tails means that dogs are happy or excited? Not necessarily. Find out more about your dog's tail and the many messages it's sending!

Why Do Dogs Wag Their Tails?


Even though your canine kids don’t speak your language, they’re excellent communicators. We humans just have to tune in and learn how to listen. Whether it’s through your dog’s expressive eyes or the subtle way he moves his ears, it all comes down to communication and body language. So, why do dogs wag their tails? To communicate! However, it wasn’t always that way.

The Canine Tail

A dog’s tail is an extension of his backbone. It’s made up of muscles and bones which join forces to form a variety of movements. Primitively it was mainly for balance, providing more control to movements like sharp turns when running or acting like a rudder when swimming.

The canine tail has evolved into a key part of the way a dog communicates. Unfortunately, we as humans don’t always understand that meaning. The movement that probably confuses us most is the “wag.” When we see a dog wagging his tail we as humans tend to get all excited because we think, “Oh wow! He’s so happy!” But beware, because the wagging tail can have many meanings and they aren’t always happy.

Think wagging tails means that dogs are happy or excited? Not necessarily. Find out more about your dog's tail and the many messages it's sending!

Let’s Talk Tail 

Tail position offers big clues into what a pooch is thinking or feeling. There are three main tail positions:

  • Low Position – When a dog holds his tail down low or between his hind legs, he’s scared or submissive. He’s showing you or another pooch that he’s not a threat.
  • Mid Position – A tail in the mid position indicates that Fido is calm, he’s interested but relaxed. He may not have figured out where this is going yet so he’s checking things out.  
  • High Position – When the tail is held in the high position it indicates dominance and confidence. It’s a threatening position or warning sign. While a dog is in a raised tail position his presence is even more pronounced due to the release of anal gland scents which penetrate the air.

Tail Movement

This is where the wag comes in. Movement can be evaluated in terms of direction and speed. The direction is an indicator of positive or negative emotions, whereas the speed indicates excitement.

A study was done by neuroscientist Giorgio Vallortigara, along with two veterinarians, in Italy. They recruited 30 mixed-breed family dogs for the study – 15 males and 15 females between the ages of 1 and 6. During the experiment, the dogs were shown positive and negative stimuli and the dogs tail movements were monitored. The end result concluded that when a positive/happy stimulus was shown, such as a dog seeing his owner, the dogs gave a speedy wag with a bias to the right. In contrast, when a negative stimulus was shown like an aggressive unfamiliar dog, their tails wagged slower with a bias to the left. 

Familiar Wagging Patterns

  • A vigorous, speedy, side-to-side wag that gets the hips and butt wiggling is a happy wag.
  • A slow wag with the tail at mid position can be letting you know that the pooch is feeling insecure.
  • A tail that’s making very small, speedy movements which appear to be vibrating could indicate that the dog is getting ready to fight or flee.
  • If the tail is in the high position as it’s vibrating – consider it a threat.

The tail is only one part of a canine’s communication toolkit. Keep in mind everything from his ears, eyes, and general mood when trying to decipher what a dog is feeling. For dogs with short stubby tails or docked tails, it will be much harder to read the signs and interpret what a dog is thinking.

Did You Know?

  •  That most puppies don’t wag until they’re around a month old and need to communicate with mom or their siblings.
  • Studies show that when no one is around a dog doesn’t wag his tail.