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Why Do Dogs Wag Their Tails?

…and puppy dog tails.

Posted June 26, 2015 in Dog Behavior

Happy dog wagging his tail

Dogs come in a multitude of sizes and shapes, and so do their tails: from the long, skinny tail of a Greyhound; to the big, bushy, curved tail of an Akita; to the little corkscrew tail of a Pug. No matter its appearance, though, your dog’s tail is a physically and emotionally moving part of his life and personality.

From a physical, utilitarian standpoint, tails in the animal kingdom serve a myriad of functions. Cows use them to swat at insects. Baby leopards and warthogs track on their mother’s tail tips to follow them through the tall grass. And monkeys use them to swing through trees. says Dogs’ tails were originally used for balance and that wagging their tails serves to transmit their individual marking scent. Beyond that, though, dogs also use their tails to communicate. The question is what are they saying? Or more specifically, what do we think they are saying?

Let’s face it. We really don’t know for sure. We can only speculate, especially since we don’t know how much of a dog’s tail movement is a result of conscious thought and how much if it is a result of unconscious thought. We do know that tails tell tales and there are some generally accepted interpretations.

What could tail position mean?

  • The higher the tail, the happier1 or more dominant the dog is in the pack hierarchy
  • A more horizontal tail indicates a content or curious dog1.
  • A lowered tail, especially if tucked between the dog’s legs, implies fear, insecurity or submission.

What could tail wagging mean?
Puppies don’t start wagging their tails until they are about 6 weeks old1 and it’s not just domesticated dogs that wag. Even wild wolves wag their tails, says At least for wolves, a rigid tail wag (like a pendulum) means the wolf is excited while a fluid wag of the tail (like a snake) signals play/greeting behavior.

According to, research shows that dogs don’t wag their tails when they are alone, even when they are presumed to be happy. There is speculation that the direction of a dog’s tail wag is significant. BBC News reports that previous research has concluded happy dogs wag their tails more to the right (from the dog’s perspective) while nervous dogs’ tails tend to go to the left. Megan Gannon of The Washington post adds that studies show dogs tend to be relaxed when other dogs wag to the right, but become stressed when other dogs wag left.

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.